- Email: [email protected]
Long-term prognostic value of IgM antibodies against phosphorylcholine for adverse cardiovascular events in patients with stable coronary heart disease
Accepted Manuscript Long-term prognostic value of IgM antibodies against phosphorylcholine for adverse cardiovascular events in patients with stable coronary heart disease Armin Imhof, Wolfgang Koenig, MD, FRCP, FESC, FACC, FAHA, Prof., Andrea Jaensch, Ute Mons, Hermann Brenner, Dietrich Rothenbacher PII:
S0021-9150(15)30170-2
DOI:
10.1016/j.atherosclerosis.2015.10.024
Reference:
ATH 14324
To appear in:
Atherosclerosis
Received Date: 13 July 2015 Revised Date:
16 October 2015
Accepted Date: 20 October 2015
Please cite this article as: Imhof A, Koenig W, Jaensch A, Mons U, Brenner H, Rothenbacher D, Long-term prognostic value of IgM antibodies against phosphorylcholine for adverse cardiovascular events in patients with stable coronary heart disease, Atherosclerosis (2015), doi: 10.1016/ j.atherosclerosis.2015.10.024. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Long-term prognostic value of IgM antibodies against phosphorylcholine for adverse cardiovascular events in patients with stable coronary heart disease. Armin Imhof1, Wolfgang Koenig1,2,3, Andrea Jaensch4,Ute Mons5,Hermann Brenner5, Dietrich Rothenbacher4,5
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Short title: IgM-antiPC in stable CHD
Dept. of Internal Medicine II - Cardiology, University of Ulm Medical Centre, Ulm, Germany
Deutsches Herzzentrum München, Technische Universität München, Munich,
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2
Germany
DZHK (German Centre for Cardiovascular Research), partner site Munich Heart
Alliance, Munich, Germany 4
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Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
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Division of Clinical Epidemiology and Aging Research C070, German Cancer
Research Center (DKFZ), Heidelberg, Germany
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Correspondence to:
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Word count: Abstract 246, Full manuscript 3633 (including references)
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Prof. Wolfgang Koenig, MD, FRCP, FESC, FACC, FAHA Klinik für Herz-& Kreislauferkrankungen Deutsches Herzzentrum München Technische Universität München Lazarettstr. 36 80636 Munich, Germany Phone: + 49-89-1218-3235 Fax: +49-89-1218-4083 Email: [email protected]
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Abstract Background: Low concentrations of IgM-phosphorylcholine autoantibodies (IgM-anti-PC) have been shown to be associated with increased risk of incident cardiovascular disease
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(CVD) events and total mortality in patients suffering from an acute coronary syndrome. We assessed whether IgM-anti-PC concentrations add prognostic information for cardiovascular risk in patients with known stable coronary artery disease (CAD).
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Methods:
IgM-anti-PC concentrations were measured in serum obtained from 1,062 patients with clinically manifest stable CAD at baseline. The relation of IgM-anti PC
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concentrations with CVD events during long-term follow-up was assessed by the Kaplan-Meier and life table method and quantified by means of the log-rank test. Then, Cox proportional hazards regression analysis was performed to assess the independent association of IgM anti-PC concentration with risk of secondary CVD events after adjustment for established and emerging risk factors. Results:
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In n=1062 patients with stable CAD only very low IgM anti-PC serum concentrations were associated with increased risk for future fatal and non-fatal coronary events (n=201 during median of 10 years of follow-up). Among patients with IgM anti-PC
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concentrations in the lowest decile, the partly adjusted hazard ratio for fatal and nonfatal coronary events was 1.60 (95% confidence interval (CI) 1.01-2.55) compared to the top quartile and 1.94 (95%-CI 1.18-3.18) after adjustment for multiple covariates.
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Conclusion:
In patients with stable CAD, very low concentrations of IgM anti-PC are associated with increased risk for fatal and non-fatal future coronary events and thus may add prognostic information to traditional cardiovascular risk factors among these patients.
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Background There is compelling evidence from experimental and clinical studies suggesting a crucial role for inflammation in the initiation and progression of atherosclerosis (1). In general, natural autoantibodies have regulatory functions in the immune system such as tumor surveillance, recognition and removal of senescent cells, cell debris, and other self-antigens (2). Phosphorylcholine is an important epitope in pro-inflammatory
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oxidized phospholipids (oxPLs), such as platelet-activating factor (PAF-) like lipids and lysophosphatidylcholine. Phosphorylcholine promotes the binding of oxPLs to the pleiotropic proinflammatory PAF receptor (3) and anti-PC inhibits the uptake of OxLDL by macrophage scavenger receptor CD36 (4,5).
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Recently, immunoglobulin-M (IgM) autoantibodies against phosphorylcholine (anti-PC) have been reported to be protective against atherothrombotic events (6).
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Anti-PC seems to have anti-inflammatory and anti-atherogenic properties. Low serum concentrations of IgM anti-PC have been shown to be associated with increased risk for recurrent acute coronary syndromes and with increased mortality among patients with acute coronary syndromes (ACS) (6). Moreover, serum IgM anti-PC titers are inversely associated with the development and progression of atherosclerosis and cardiovascular disease (CVD) (7,8). Among chronic dialysis patients, low serum
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concentrations of IgM anti-PC were associated with increased mortality (9). However, in the ATLAS-TIMI 46 Trial among patients with ACS there was no association between autoantibodies to phosphorylcholine and future CVD events or mortality (10). At present, no data describing the association between IgM anti-PC and
been reported.
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recurrent cardiovascular events and mortality in patients with known stable CAD has
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Thus, the present study aimed to determine the association of serum concentrations of IgM anti-PC antibodies with subsequent adverse CVD events and all-cause mortality in patients with stable CHD during long-term follow-up.
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Material and Methods Study population All patients with CHD (International Classification of Diseases, 9th Rev. codes. 410414) aged 30-70 years who chose to participate in an in-hospital rehabilitation program between January 1999 and May 2000 in two cooperating hospitals
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(Schwabenland-Klinik, Isny and Klinikum Südpark, Bad Nauheim, Germany) were enrolled in the study (initial response rate 58% and clinically relevant CHD was defined by a greater than 50% diameter stenosis of 1 or more major epicardial coronary arteries). In Germany, all patients after an ACS or elective coronary artery
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bypass grafting (CABG) are offered a comprehensive in-hospital rehabilitation program after discharge from the acute care hospital. The aim of this 3-week
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program is the reduction of cardiovascular risk factors, improvement of health related quality of life, and the preservation of the ability to work (the latter only if a participant was working at the onset of disease, otherwise the prevention of nursing care). This in-hospital rehabilitation program usually starts approximately three weeks after the acute event or CABG. Although we recruited patients only in two such in-patient rehabilitation centers (in the south of Germany and in central Germany), these
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specialized centers serve a large geographic area with a radius of up to 200 km, and therefore, patients were referred from a large number of different acute care hospitals. In the current study, only patients who were admitted within three months of the acute event or CABG were included.
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All participants gave written informed consent. The study was approved by the Ethics Boards of the Universities of Ulm and Heidelberg and of the Physicians’
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Chamber of the States of Baden-Wuerttemberg and Hessen (Germany). Data collection
At the beginning of the in-hospital rehabilitation program all participants filled out a standardized questionnaire containing socio-demographic information and medical history including also information on history of hypertension, myocardial infarction, and diabetes. In addition, information was taken from the patients’ hospital charts. In all patients active follow-up was conducted 1, 3, 4, 5, 6, 8 and 10 years after discharge from the rehabilitation center. Information was obtained from the patients using a mailed standardized questionnaire. Information regarding secondary CVD events and treatment since discharge from the in-hospital rehabilitation clinic was 4
ACCEPTED MANUSCRIPT obtained from the primary care physicians also by means of a standardized questionnaire. If a participant had died during follow-up, the death certificate was obtained from the local Public Health Department and the main cause of death was coded according to the International Classification of Diseases (ICD-9 pos. 390-459: ICD-10 pos. I0-I99 and R57.0). Secondary CVD events were defined either as CVD as the main cause of death (as stated in the death certificate), non-fatal myocardial
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infarction (MI), or non-fatal stroke. All non-fatal secondary events were reported by the primary care physicians. Laboratory methods
43
days
after
the
acute
event;
1st
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Blood at baseline was drawn at discharge from the rehabilitation centre (on average quartile
36
days,
3rd
quartile
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51 days) in a fasting state under standardized conditions and stored at -80°C until analysis. IgM anti-PC measurements by enzyme-linked immunosorbent assay using the CVDefine kit (Athera Biotechnologies, Solna, Sweden). This assay employs an immobilized, conjugated PC antigen, and human anti-PC IgM for standards (11). All cTnT measurements were performed by a high-sensitivity (hs) assay (Roche Diagnostics, Penzberg, Germany) on an Elecsys 2010 platform. A value of 14 ng/L
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has been reported to represent the 99th percentile in a healthy reference population (12). The inter-assay coefficients of variation were 3.6% and 2.9% at concentrations of 42 and 2.82 ng/L. C-reactive protein (CRP) concentrations were measured by latex-enhanced immunonephelometry on a Behring Nephelometer II (N Latex CRP
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mono Dade-Behring). Cystatin C was determined on the same device (DadeBehring) (13). NT-proBNP was measured by electrochemiluminescence on an
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Elecsys 170 (Roche Diagnostics) (14). Lipoprotein-associated phospholipase A2 (LpPLA2) and secretory phospholipase A2 (sPLA2) mass and activity were determined as reported previously (15,16). Inter-assay coefficients of variation (CVs) were 4.1% for hsCRP, 3.8% for
cystatin C, between 3% (for a target value 4970 pg/ml) and 7% (for a target value 178 pg/ml) for NT-proBNP. All markers were measured in a blinded fashion. Creatinine, blood lipids and leukocyte count were determined by routine methods in both participating hospitals.
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ACCEPTED MANUSCRIPT Statistical methods The study population has been described with respect to various sociodemographic and clinical characteristics. The associations of sociodemographic characteristics, various cardiovascular risk factors, and medication with IgM-anti PC concentrations were quantified by means of the non-parametric Kruskal-Wallis test. Partial
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Spearman correlation coefficients, adjusted for age and gender, were calculated for hs-cTnT concentrations and blood lipids, hsCRP, creatinine, cystatin C, NT-proBNP, as well as Lp-PLA2 and sPLA2.
The relation of IgM-anti PC concentrations with adverse CVD events during follow-up was assessed by the Kaplan-Meier and life table method and quantified by
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means of the log-rank test. Then, Cox proportional hazards regression analysis was employed to assess the independent association of IgM-anti PC concentration with
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the risk of secondary CVD events (hazard ratios, HR, and their 95% confidence intervals, CI). A basic model was adjusted for age (years) and gender. In a second step, potential confounding variables were added in the model to the main factor IgM anti-PC and the variables age and gender. The following potential confounders were considered in multivariable analyses: body mass index (BMI, kg/m2), smoking status (never, current, former-smoker) duration of school education (< 10 years, ≥10 years),
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hospital site (Isny, Bad Nauheim), marital status (married, other), history of MI (yes, no), history of hypertension (yes, no), history of diabetes mellitus (yes, no), severity of CHD (number of affected epicardial coronary vessels at baseline), initial
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management of CHD (conservative, percutaneous coronary intervention, PCI, coronary artery bypass grafting, CABG), intake of ß-blockers (yes, no), intake of ACE-inhibitors (yes, no), intake of diuretics (yes, no), intake of lipid-lowering drugs
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(yes, no), intake of anti-diabetic drugs (yes, no), intake of anti-hypertensive drugs (yes, no), intake of anti-platelet drugs (yes, no), HDL-cholesterol (mg/dl), LDLcholesterol (mg/dl). To avoid overadjustment, only those variables were added to the model which were significant predictors of a secondary event at an α-level of 0.1 or which changed the parameter estimates for the main variables (IgM-anti PC) by more than 10%. A final modelling step was performed to adjust for biomarkers related to IgM-anti PC (i.e. hs-TnT, cystatin C, and NT-proBNP). In addition, we also used a spline regression (with 4 degrees of freedom) for multivariate analysis. All statistical procedures were performed with the SAS statistical software package (release 8.2 SAS Institute Inc. ).
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Results The main sociodemographic, clinical and laboratory characteristics of the 1,062 patients with clinically manifest CHD are shown in Table 1. The mean age of these CHD patients (84.9% men) was 58.9 years. About two third (58.5%) had a history of myocardial infarction with 12.7% reporting symptomatic heart failure. Body mass index was 26.9 kg/m² and 17.0% were diabetic. Mean GRACE Score was 96.1 (SD
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20.8). The majority of patients had a normal renal function according to creatinine and serum concentrations of cystatin C. Median serum concentrations of IgM anti-PC were 49.2 U/ml. Cut point for the lowest 10% of the distribution of IgM anti-PC was <21.3 U/ml.
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As depicted in Table 2 median IgM anti-PC concentrations were significantly lower among males, although the proportion in the <10th percentile was similar
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among men and women. Median IgM anti-PC in men was lower also in the highest age category, never smokers, and among patients with history of hypertension. Furthermore, we found lower median concentrations with increasing extension of CAD with respect to number of vessels affected. Remarkably, patients with a history of acute myocardial infarction (MI) showed higher concentrations of IgM anti-PC compared to those without and a conservative initial management strategy in the
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acute situation was associated with substantially higher IgM anti-PC titers compared to a interventional or a surgical strategy. Use of lipid-lowering agents was also associated with higher serum concentrations of IgM anti-PC whereas history of
PC. (Table 2)
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diabetes and intake of anti-diabetic medication were associated with lower IgM anti-
As shown in Table 3 we found no substantial association between IgM anti-PC
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serum concentration and lipids, markers of renal function and all other biomarkers measured including markers of inflammation, heart failure and hs-troponin T after adjustment for age and gender. A weak positive correlation was found with hstroponin I
As depicted in Figure 1, comparing recurrent fatal and non-fatal CVD events
did not show a difference between IgM anti-PC concentrations. However, when looking closer to the lower end of the distribution, those in the lowest 10% of the IgM anti-PC distribution showed a significantly increased risk of adverse cardiovascular events during follow-up with an incidence of 38.3 per 1000 patient years within the latter group (p-value of log-rank test = 0.02).
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ACCEPTED MANUSCRIPT Table 4 then shows the results after multivariable adjustment for covariates. No association was found if the hazard associated with IgM anti-PC was investigated in quartiles. However, if the bottom quartile was split into two categories, subjects in the lowest 10% (i.e. <21.3 U/ml) of the IgM anti-PC distribution showed a hazard ratio (HR) of 1.60 (95% confidence interval (CI) 1.01-2.55). After adjustment for further covariates the HR increased to 1.75 (95% CI 1.07-2.84) and was even increased to
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an HR of 1.94 (95% CI 1.18-3.18) after additional adjustment for cystatin C, NTproBNP and hs-troponin T. (CRP was neither related to IgM anti-PC nor to adverse CVD events – latter data not shown).
Figure. 2 shows splines representing IgM anti-PC associated with hazard for
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adverse CVD events after adjustment for covariates indicating that only very low IgM
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anti-PC concentrations are associated with increased risk for recurrent events.
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Discussion In this observational prospective study with long-term follow-up in more than 1000 patients with stable CHD at baseline we measured natural antibodies against phosphorylcholine (IgM anti-PC) and found an increased risk for recurrent CV events in patients in the very low end of the distribution, which persisted after adjustment for
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a variety of traditional and emerging CVD risk factors as well as markers of left ventricular and renal function, and cardiac damage.
Natural antibodies against phosphorylcholine (IgM anti-PC) seem to be crucial in the elimination of pro-inflammatory oxidized phospholipids (oxPLs) and apoptotic
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cells (17) and thus showing anti-atherogenic properties. Elevated IgM anti-PC concentrations have been proven beneficial in animal models of vascular disease
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potentially by inhibiting the uptake of ox-LDL into macrophages (18,19). In contrast, low concentrations of IgM anti-PC indicate a reduced defence mechanism and may be associated with accelerated atherosclerosis including increased risk of acute cardiovascular events (6).
We could demonstrate a significant and independent association between very low concentrations of IgM anti-PC antibodies and long-term increased risk of future
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fatal and non-fatal cardiovascular events among patients in the stable phase of CAD. Prior studies have shown conflicting results on the association between IgM anti-PC antibodies and risk of future cardiovascular events in various populations. Among patients with hypertension, after suffering from stroke, patients on chronic dialysis
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and after recent MI low concentrations of IgM anti-PC were predictive for cardiovascular events (4,7,8,11,20). Moreover, in a small study of fifty-six patients
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with severe peripheral artery disease (PAD) after surgical revascularisation concentrations of IgM anti-PC in the lowest quartile of the distribution were associated with statistically significant worse bypass graft patency (21). In the PRACSIS registry (Prognosis and Risk in Acute Coronary Syndrome in Schweden, 1995-2001) low levels of IgM anti-PC titers were found to be independently associated with a composite of major cardiac events and all-cause mortality during short (6 months), intermediate (18 months) and long-term (72 months) follow-up. This held true even when comparing those patients below median concentrations with those showing levels above the median. Only for the endpoint mortality after 72 months the hazard ratio lost its statistical significance (6).
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ACCEPTED MANUSCRIPT However, in the large prospective ATLAS ACS-TIMI 46 Trial, a multicenter, multinational dose ranging trial of rivaroxaban including 3,491 patients with ACS, Geller et al. neither found an association between IgM anti-PC concentrations and future cardiovascular events nor with mortality (10). Although the authors compared risk for the defined endpoints according to the quartiles of distribution and using a cut-point of 17 U/ml for further analyses as suggested in other studies they found no
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association. Very recently, Gimenez et al. also reported no association between IgM anti-PC and major adverse cardiovascular events (MACE) in a prospective study including 1072 patients with NSTEMI. Longest follow-up in this study was 12 months and a pre-defined cut-off of <29 U/ml was used to identify patients at risk (22). This is
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quite consistent with our findings where the lowest quartile of the IgM anti-PC distribution (cut-off <31.2U/ml) also was not associated with future recurrent CVD
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events. However, we found a strong and independent association with CVD events and mortality among those with very low concentrations of IgM anti-PC (<21.3 U/L i.e. lowest 10% of the distribution). In addition, follow-up was 6 months in the ATLAS ACS-TIMI 46 Trial and up to 12 months in the study reported by Gimenez et al. and thus substantially shorter compared to our study. Also the number of events in these studies was much smaller.
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Although these results are somewhat conflicting, the majority of data reported so far suggest that subjects with low concentrations of IgM anti-PC are at increased risk for future cardiovascular events. However, future studies are needed focusing on individuals with very low IgM anti-PC titers and with respect to intra-individual
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variations of anti-PC concentrations over time to evaluate the potential of therapeutical interventions initiated in these patients. Nevertheless, there are data
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showing that IgM anti-PC concentrations are relatively stable over time (23). Our study has several strengths but also limitations which should be
considered. The large sample size of well defined patients with stable CAD and longterm follow up are important strengths of the present study. However, using only one time-point of IgM anti-PC at baseline we were not able to analyse risk over time according to intra-individual variation. In addition, using a very low cut-point in a secondary analysis approach reduced numbers of individuals in the analysed subgroups and thus increased the risk of chance findings. Therefore, these results need to be replicated in similar large patient populations. Future studies should explore whether besides identifying patients at high risk for future adverse CVD events IgM anti-PC might present a new therapeutic target in 10
ACCEPTED MANUSCRIPT this albeit relatively small group of patients with very low concentrations of this molecule. In conclusion, in patients with stable CAD very low concentrations of IgM-antiPC are associated with increased risk for recurrent fatal and non-fatal future CVD events. If corroborated in future studies, IgM anti-PC concentrations may add prognostic information in addition to traditional and emerging cardiovascular risk
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markers among these patients and thus may improve risk stratification in the future.
Funding: Funding was received from the German Federal Ministry of Education and
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Research (01GD9820/0 and 01ER0814) and the Pitzer Foundation, Bad Nauheim, Germany. The funders played no role in design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or
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approval of the manuscript.
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References 1. Libby P, Hansson GK. Inflammation and immunity in diseases of the arterial tree: players and layers. Circ
Res.
2015
Jan
16;116(2):307-11.
doi:
10.1161/CIRCRESAHA.116.301313.
RI PT
2. Chou MY, Fogelstrand L, Hartvigsen K, Hansen LF, Woelkers D, Shaw PX, Choi J, Perkmann T, Bäckhed F, Miller YI, Hörkkö S, Corr M, Witztum JL, Binder CJ.
Oxidation-specific epitopes are dominant targets of innate natural antibodies in mice and humans.
SC
J Clin Invest. 2009 May;119(5):1335-49. doi: 10.1172/JCI36800. 3. Frostegård J, Huang YH, Rönnelid J, Schäfer-Elinder L.
common mechanism.
M AN U
Platelet-activating factor and oxidized LDL induce immune activation by a
Arterioscler Thromb Vasc Biol. 1997 May;17(5):963-8. 4. de Faire U, Su J, Hua X, Frostegård A, Halldin M, Hellenius ML, Wikström M, Dahlbom I, Grönlund H, Frostegård J.
Low levels of IgM antibodies to phosphorylcholine predict cardiovascular
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disease in 60-year old men: effects on uptake of oxidized LDL in macrophages as a potential mechanism.
J Autoimmun. 2010 Mar;34(2):73-9. doi: 10.1016/j.jaut.2009.05.003.
JL.
EP
5. Binder CJ, Chang MK, Shaw PX, Miller YI, Hartvigsen K, Dewan A, Witztum
Innate and acquired immunity in atherogenesis.
AC C
Nat Med. 2002 Nov;8(11):1218-26.
6. Caidahl K, Hartford M, Karlsson T, Herlitz J, Pettersson K, de Faire U, Frostegård J.
IgM-phosphorylcholine autoantibodies and outcome in acute coronary syndromes. Int J Cardiol. 2013 Jul 31;167(2):464-9. doi: 10.1016/j.ijcard.2012.01.018.
7. Fiskesund R, Stegmayr B, Hallmans G, Vikström M, Weinehall L, de Faire U, Frostegård J. Low levels of antibodies against phosphorylcholine predict development of stroke in a population-based study from northern Sweden. Stroke. 2010 Apr;41(4):607-12. doi: 10.1161/STROKEAHA.109.558742. 12
ACCEPTED MANUSCRIPT 8. Su J, Georgiades A, Wu R, Thulin T, de Faire U, Frostegård J. Antibodies of IgM subclass to phosphorylcholine and oxidized LDL are protective factors for atherosclerosis in patients with hypertension. Atherosclerosis. 2006 Sep;188(1):160-6. 9. Carrero JJ, Hua X, Stenvinkel P, Qureshi AR, Heimbürger O, Bárány P, Lindholm B, Frostegård J.
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Low levels of IgM antibodies against phosphorylcholine-A increase mortality risk in patients undergoing haemodialysis.
Nephrol Dial Transplant. 2009 Nov;24(11):3454-60. doi: 10.1093/ndt/gfp309. 10. Geller BJ, Mega JL, Morrow DA, Guo J, Hoffman EB, Gibson CM, Ruff CT.
SC
Autoantibodies to phosphorylcholine and cardiovascular outcomes in patients with acute coronary syndromes in the ATLAS ACS-TIMI 46 trial.
0968-y.
M AN U
J Thromb Thrombolysis. 2014 Apr;37(3):310-6. doi: 10.1007/s11239-013-
11. Sjöberg BG, Su J, Dahlbom I, Grönlund H, Wikström M, Hedblad B, Berglund G, de Faire U, Frostegård J.
Low levels of IgM antibodies against phosphorylcholine-A potential risk marker for ischemic stroke in men.
07.009.
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Atherosclerosis. 2009 Apr;203(2):528-32) doi: 10.1016/j.atherosclerosis.2008.
12. Giannitsis E, Kurz K, Hallermayer K, Jarausch J, Jaffe AS, Katus HA. Analytical validation of a high-sensitivity cardiac troponin T assay.
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Clin Chem. 2010 Feb;56(2):254-61. doi: 10.1373/clinchem.2009.132654. 13. Koenig W, Twardella D, Brenner H, Rothenbacher D.
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Plasma concentrations of cystatin C in patients with coronary heart disease and risk for secondary cardiovascular events: more than simply a marker of glomerular filtration rate. Clin Chem. 2005 Feb;51(2):321-7.
14. Rothenbacher D, Koenig W, Brenner H. Comparison of N-terminal pro-B-natriuretic peptide, C-reactive protein, and creatinine clearance for prognosis in patients with known coronary heart disease. Arch Intern Med. 2006 Dec 11-25;166(22):2455-60. 15. Koenig W, Twardella D, Brenner H, Rothenbacher D.
13
ACCEPTED MANUSCRIPT Lipoprotein-associated phospholipase A2 predicts future cardiovascular events in patients with coronary heart disease independently of traditional risk factors, markers of inflammation, renal function, and hemodynamic stress. Arterioscler Thromb Vasc Biol. 2006 Jul;26(7):1586-93. 16. Koenig W, Vossen CY, Mallat Z, Brenner H, Benessiano J, Rothenbacher D. Association
between
type
II
secretory
phospholipase
A2
plasma
RI PT
concentrations and activity and cardiovascular events in patients with coronary heart disease.
Eur Heart J. 2009 Nov;30(22):2742-8. doi: 10.1093/eurheartj/ehp302.
Witztum JL.
SC
17. Shaw PX, Hörkkö S, Chang MK, Curtiss LK, Palinski W, Silverman GJ,
Natural antibodies with the T15 idiotype may act in atherosclerosis, apoptotic
M AN U
clearance, and protective immunity. J Clin Invest. 2000 Jun;105(12):1731-40.
18. Caligiuri G, Khallou-Laschet J, Vandaele M, Gaston AT, Delignat S, Mandet C, Kohler HV, Kaveri SV, Nicoletti A.
Phosphorylcholine-targeting immunization reduces atherosclerosis. J Am Coll Cardiol. 2007 Aug 7;50(6):540-6.
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19. Faria-Neto JR, Chyu KY, Li X, Dimayuga PC, Ferreira C, Yano J, Cercek B, Shah PK. Passive
immunization
phosphorylcholine
with
reduces
monoclonal
accelerated
IgM
vein
antibodies
graft
against
atherosclerosis
in
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apolipoprotein E-null mice. Atherosclerosis. 2006 Nov;189(1):83-90.
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20. Grönlund H, Hallmans G, Jansson JH, Boman K, Wikström M, de Faire U, Frostegård J.
Low levels of IgM antibodies against phosphorylcholine predict development of acute myocardial infarction in a population-based cohort from northern Sweden. Eur
J
Cardiovasc
Prev
Rehabil.
2009
Jun;16(3):382-6.
doi:
10.1097/HJR.0b013e32832a05df. 21. Sobel M, Moreno KI, Yagi M, Kohler TR, Tang GL, Clowes AW, Zhou XH, Eugenio E. Low levels of a natural IgM antibody are associated with vein graft stenosis and failure. 14
ACCEPTED MANUSCRIPT J Vasc Surg. 2013 Oct;58(4):997-1005.e1-2. doi: 10.1016/j.jvs.2013.04.042. 22. Rubini Gimenez M, Pagano S, Virzi J, Montecucco F, Twerenbold R, Reichlin T, Wildi K, Grueter D, Jaeger C, Haaf P, Vuilleumier N, Mueller C. Diagnostic and prognostic value of autoantibodies anti-apolipoprotein A-1 and anti-phosphorylcholine in acute non-ST elevation myocardial infarction. Eur J Clin Invest. 2015 Apr;45(4):369-79. doi: 10.1111/eci.12411.
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23. Fiskesund R, Su J, Bulatovic I, Vikström M, de Faire U, Frostegård J.
IgM phosphorylcholine antibodies inhibit cell death and constitute a strong protection marker for atherosclerosis development, particularly in combination with other auto-antibodies against modified LDL.
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Results Immunol. 2012 Jan 8;2:13-8. doi: 10.1016/j.rinim.2012.01.001.
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eCollection 2012.
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ACCEPTED MANUSCRIPT Table 1. Sociodemographic, clinical, and laboratory characteristics in 1,062 patients with clinically manifest coronary heart disease
Age (years) (µ, SD)
58.9 ± 8.0
Men, n (%)
902 (84.9%)
History of myocardial infarction, n (%)
621 (58.5%)
History of heart failure, n (%)
131 (12.7%)
Clinical score (angiographic evaluation) 258 (24.3%)
- 2 vessel disease
282 (26.6%)
- 3 vessel disease
455 (42.8%)
- unknown
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- 1 vessel disease
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Characteristics at Baseline
52 (4.9%)
School education <10 yr, n (%) Body mass index (kg/m2), (µ, SD)
GRACE Score (µ, SD)
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History of diabetes, n (%)
637 (60.0%) 26.9 ± 3.2
181 (17.0%) 96.1 (20.8) 169.1 (32.8)
LDL-cholesterol (mg/dl) (µ, SD)
101.1 (29.6)
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Total cholesterol (mg/dl) (µ, SD)
39.4 (10.5)
C-reactive protein (mg/L) *
3.51 (1.26; 8.40)
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HDL-cholesterol (mg/dl) (µ, SD)
Cystatin C (mg/L)*
1.03 (0.93; 1.19)
NT-proBNP (pg/mL)*
568.85 (277.60; 1101.00)
hs-troponin T* (ng/L)
13.9 (8.9-21.9)
hs-troponin I * (pg/mL)
14.3 (9.4-23.8)
MR-proANP* (pmol/L)
135.4 (95.2;185.9)
IgM-antiPC* (U/ml)
49.2 (31.2;77.7)
* median, 25th and 75th quantile cut-point
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ACCEPTED MANUSCRIPT Table 2. IgM-antiPC distribution (Median) and in lower 10 percentile according to various sociodemographic characteristics, cardiovascular risk factors, and ECG findings IgM-antiPC Distribution Median
School education
- Female
160
56.1
- Male
902
48.2
- 30-39
24
68.7
8.3%
- 40-49
130
62.3
6.2%
- 50-59
307
54.9
- 60-70
601
43.6
- < 10 yrs. 637
51.7
- ≥ 10 yrs. 425
Body mass index 2
(kg/m )
- Married
881
- Other
181
- < 25
294
- 25-30
603
- >30 Smoking status
51.2
0.03
9.8%
<0.0001
12.5%
0.07
10.8%
0.72
8.8%
10.1%
49.8
- Never
334
41.9
17.4%
- Ex
676
53.0
6.2%
52
54.1
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50.6
- Yes
621
51.9
- No
441
44.2
History of
- Yes
589
45.4
hypertension
- No
473
54.1
History of heart
- Yes
131
45.4
failure
- No
897
49.3
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881
0.40
10.1%
49.3
- No
0.014
9.3%
8.2%
43.6
0.73
6.5%
47.6
181
p-value**
10.6%
49.0
- Yes
History of MI
<10th percentile
161
- Current History of diabetes
46.4
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Family status
p-value*
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(U/ML)
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Age (years)
N
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Gender
Proportion in
0.88
<0.0001
12.4%
9.6%
0.60
0.34
<0.0001
11.6% 0.06
9.5%
0.40
8.9% 0.002
11.3%
0.18
10.7% 0.001
8.9%
0.32
13.0% 0.30
9.1%
0.16
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ACCEPTED MANUSCRIPT Cont. table 2 IgM-antiPC Distribution Median N
(U/ml)
Proportion in p-value* <10th percentile p-value**
- Zero/one
273
52.4
9.2%
(number of affected
- Two
282
51.2
9.2%
vessels)
- Three
455
46.0
Initial management of - Conservative
192
55.9
CHD
- PCI
363
50.6
- CABG
507
44.3
Left ventricular
- No/only little
757
49.3
function*
- Modest/severe
218
50.5
(degree of impairment)
- Unknown
87
46.8
Intake of lipid-
- Yes
818
51.2
lowering agent
- No
242
45.0
154
43.0
906
50.1
0.03
drugs
- No
Intake of anti-
- Yes
hypertensive drugs
- No
28
Intake of anti-platelet
- Yes
1040 49.0
drugs
- No
20
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62.5
0.57
9.4%
11.4%
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0.001
0.17
10.3% 8.7%
0.96
0.05
0.05
1032 49.5 45.6
11.2%
6.8%
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Intake of anti-diabetic - Yes
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Angiographic score
0.81
9.2%
0.77
8.8% 13.6%
0.03
12.3% 9.5%
0.27
10.1% 3.6%
0.26
9.8% 0.55
15.0%
0.44
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*Kruskal-Wallis Test, **Chi-Square Test
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ACCEPTED MANUSCRIPT Table 3. Partial Spearman rank correlation coefficients (R) between established and emerging risk factors of coronary heart disease (age and gender adjusted). IgM-antiPC p-value
HDL cholesterol [mmol/L]
-0.05
0.10
Total cholesterol [mmol/L]
0.05
0.13
LDL cholesterol [mmol/L]
0.04
0.17
Leukocytes [G/L]
0.04
0.23
C-reactive protein [mg/L]
0.03
Interleukin-6 [pg/mL]
0.0006
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R
0.27
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1.00
Adiponectin [µg/ml]
-0.01
0.74
0.06
0.06
0.06
0.05
0.001
0.96
0.02
0.42
-0.01
0.74
0.08
0.01
0.05
0.07
0.04
0.22
ICAM [nmol]
-0.02
0.51
MR-proANP (pmol/L)
0.03
0.29
GDF 15 [pg/mL]
0.02
0.61
sST2 [ng/mL]
0.05
0.11
Cystatin C [mg/L] NT-proBNP [pg/mL]
Creatinine [µmol/] Hs-Troponin T [ng/L]
HbA1c (%)
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sPLA2 [ng/mL]
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Hs-Troponin I [pg/mL]
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Lp-PLA2 mass [ng/mL]
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ACCEPTED MANUSCRIPT Table 4: Association of IgM-antiPC with fatal and non-fatal cardiovascular events during follow-up Results of Multivariable Analysis HR (95 % CI)
Adjusted for age
*Adjusted for multiple **Adjusted for
and gender
covariates
Top Quartile
1 referent
1 referent
Third
1.18 (0.80-1.75)
1.14 (0.76-1.70)
1.26 (0.84-1.91)
Second
1.01 (0.67-1.51)
1.03 (0.68-1.56)
1.12 (0.73-1.72)
Bottom Quartile
1.00 (0.67-1.50)
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p for trend: 0.78
multiple covariates
1 referent
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IgM-antiPC
HR (95 % CI)
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HR (95 % CI)
1.14 (0.74-1.74)
p for trend: 0.84
p for trend: 0.72
25%-10%
0.64 (0.38-1.09)
0.61 (0.35-1.05)
0.69 (0.40-1.22)
<10% ***
1.60 (1.01-2.55)
1.75 (1.07-2.84)
1.94 (1.18-3.18)
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* adjusted for age, gender, rehabilitation clinic, history of diabetes mellitus, smoking status, PCI, CABG, HDL-cholesterol, LDL-cholesterol, intake of lipid-lowering drugs, intake of anti-diabetic drugs, intake of anti-hypertensive drugs **adjusted for all covariates above and (log-transformed concentrations) of cystatin C, Nt-proBNP and hs-TNI.
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*** bottom quartile splitted in two categories: 25%-10% and <10%
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ACCEPTED MANUSCRIPT Figure 1: Kaplan-Meier estimates of secondary fatal and non-fatal CVD events
1000 937
EP
500 966
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Follow-up time Persons under risk
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SC
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during follow-up (time=years) according to quartiles of IgM-antiPC
1500 895
2000 838
2500 767
Fatal and non-fatal CVD event during follow-up, N (Incidence*) 46 (21.2)
3000 691
IgM-antiPC
N
>77.66 (top quartile)
265
>49.16 – 77.66
266
55 (26.2)
>31.20 – 49.16
264
50 (23.3)
<31.20 (bottom quartile)
267
50 (24.0)
0.73
20 (15.4) 30 (38.3) 201 (23.7)
0.02
>21.30 – 31.20 *** <21.30
160 107 1,062
3500 614
p-Value**
* per 1,000 patient years ** Log Rank Test *** Bottom quartile splitted in two categories: 25%-10% and <10% 1
ACCEPTED MANUSCRIPT Fig. 2: Splines representing IgM-antiPC associated with hazard for adverse
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EP
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SC
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CVD events after adjustment for covariates
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ACCEPTED MANUSCRIPT Highlights
Low concentrations of IgM phosphorylcholine autoantibodies (IgM anti-PC), are involved in inflammation and predict risk for recurrent events in ACS patients
•
The predictive value of IgM anti-PC for long-term prognosis in stable CHD patients is largely unknown
•
In 1,062 patients with stable CHD very low levels of IgM anti-PC were associated with increased risk for future coronary events
•
IgM anti-PC may add prognostic information to traditional risk factors
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•
S0021-9150(15)30170-2
DOI:
10.1016/j.atherosclerosis.2015.10.024
Reference:
ATH 14324
To appear in:
Atherosclerosis
Received Date: 13 July 2015 Revised Date:
16 October 2015
Accepted Date: 20 October 2015
Please cite this article as: Imhof A, Koenig W, Jaensch A, Mons U, Brenner H, Rothenbacher D, Long-term prognostic value of IgM antibodies against phosphorylcholine for adverse cardiovascular events in patients with stable coronary heart disease, Atherosclerosis (2015), doi: 10.1016/ j.atherosclerosis.2015.10.024. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Long-term prognostic value of IgM antibodies against phosphorylcholine for adverse cardiovascular events in patients with stable coronary heart disease. Armin Imhof1, Wolfgang Koenig1,2,3, Andrea Jaensch4,Ute Mons5,Hermann Brenner5, Dietrich Rothenbacher4,5
1
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Short title: IgM-antiPC in stable CHD
Dept. of Internal Medicine II - Cardiology, University of Ulm Medical Centre, Ulm, Germany
Deutsches Herzzentrum München, Technische Universität München, Munich,
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2
Germany
DZHK (German Centre for Cardiovascular Research), partner site Munich Heart
Alliance, Munich, Germany 4
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3
Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
5
Division of Clinical Epidemiology and Aging Research C070, German Cancer
Research Center (DKFZ), Heidelberg, Germany
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Correspondence to:
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Word count: Abstract 246, Full manuscript 3633 (including references)
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Prof. Wolfgang Koenig, MD, FRCP, FESC, FACC, FAHA Klinik für Herz-& Kreislauferkrankungen Deutsches Herzzentrum München Technische Universität München Lazarettstr. 36 80636 Munich, Germany Phone: + 49-89-1218-3235 Fax: +49-89-1218-4083 Email: [email protected]
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Abstract Background: Low concentrations of IgM-phosphorylcholine autoantibodies (IgM-anti-PC) have been shown to be associated with increased risk of incident cardiovascular disease
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(CVD) events and total mortality in patients suffering from an acute coronary syndrome. We assessed whether IgM-anti-PC concentrations add prognostic information for cardiovascular risk in patients with known stable coronary artery disease (CAD).
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Methods:
IgM-anti-PC concentrations were measured in serum obtained from 1,062 patients with clinically manifest stable CAD at baseline. The relation of IgM-anti PC
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concentrations with CVD events during long-term follow-up was assessed by the Kaplan-Meier and life table method and quantified by means of the log-rank test. Then, Cox proportional hazards regression analysis was performed to assess the independent association of IgM anti-PC concentration with risk of secondary CVD events after adjustment for established and emerging risk factors. Results:
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In n=1062 patients with stable CAD only very low IgM anti-PC serum concentrations were associated with increased risk for future fatal and non-fatal coronary events (n=201 during median of 10 years of follow-up). Among patients with IgM anti-PC
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concentrations in the lowest decile, the partly adjusted hazard ratio for fatal and nonfatal coronary events was 1.60 (95% confidence interval (CI) 1.01-2.55) compared to the top quartile and 1.94 (95%-CI 1.18-3.18) after adjustment for multiple covariates.
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Conclusion:
In patients with stable CAD, very low concentrations of IgM anti-PC are associated with increased risk for fatal and non-fatal future coronary events and thus may add prognostic information to traditional cardiovascular risk factors among these patients.
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Background There is compelling evidence from experimental and clinical studies suggesting a crucial role for inflammation in the initiation and progression of atherosclerosis (1). In general, natural autoantibodies have regulatory functions in the immune system such as tumor surveillance, recognition and removal of senescent cells, cell debris, and other self-antigens (2). Phosphorylcholine is an important epitope in pro-inflammatory
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oxidized phospholipids (oxPLs), such as platelet-activating factor (PAF-) like lipids and lysophosphatidylcholine. Phosphorylcholine promotes the binding of oxPLs to the pleiotropic proinflammatory PAF receptor (3) and anti-PC inhibits the uptake of OxLDL by macrophage scavenger receptor CD36 (4,5).
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Recently, immunoglobulin-M (IgM) autoantibodies against phosphorylcholine (anti-PC) have been reported to be protective against atherothrombotic events (6).
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Anti-PC seems to have anti-inflammatory and anti-atherogenic properties. Low serum concentrations of IgM anti-PC have been shown to be associated with increased risk for recurrent acute coronary syndromes and with increased mortality among patients with acute coronary syndromes (ACS) (6). Moreover, serum IgM anti-PC titers are inversely associated with the development and progression of atherosclerosis and cardiovascular disease (CVD) (7,8). Among chronic dialysis patients, low serum
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concentrations of IgM anti-PC were associated with increased mortality (9). However, in the ATLAS-TIMI 46 Trial among patients with ACS there was no association between autoantibodies to phosphorylcholine and future CVD events or mortality (10). At present, no data describing the association between IgM anti-PC and
been reported.
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recurrent cardiovascular events and mortality in patients with known stable CAD has
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Thus, the present study aimed to determine the association of serum concentrations of IgM anti-PC antibodies with subsequent adverse CVD events and all-cause mortality in patients with stable CHD during long-term follow-up.
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Material and Methods Study population All patients with CHD (International Classification of Diseases, 9th Rev. codes. 410414) aged 30-70 years who chose to participate in an in-hospital rehabilitation program between January 1999 and May 2000 in two cooperating hospitals
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(Schwabenland-Klinik, Isny and Klinikum Südpark, Bad Nauheim, Germany) were enrolled in the study (initial response rate 58% and clinically relevant CHD was defined by a greater than 50% diameter stenosis of 1 or more major epicardial coronary arteries). In Germany, all patients after an ACS or elective coronary artery
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bypass grafting (CABG) are offered a comprehensive in-hospital rehabilitation program after discharge from the acute care hospital. The aim of this 3-week
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program is the reduction of cardiovascular risk factors, improvement of health related quality of life, and the preservation of the ability to work (the latter only if a participant was working at the onset of disease, otherwise the prevention of nursing care). This in-hospital rehabilitation program usually starts approximately three weeks after the acute event or CABG. Although we recruited patients only in two such in-patient rehabilitation centers (in the south of Germany and in central Germany), these
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specialized centers serve a large geographic area with a radius of up to 200 km, and therefore, patients were referred from a large number of different acute care hospitals. In the current study, only patients who were admitted within three months of the acute event or CABG were included.
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All participants gave written informed consent. The study was approved by the Ethics Boards of the Universities of Ulm and Heidelberg and of the Physicians’
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Chamber of the States of Baden-Wuerttemberg and Hessen (Germany). Data collection
At the beginning of the in-hospital rehabilitation program all participants filled out a standardized questionnaire containing socio-demographic information and medical history including also information on history of hypertension, myocardial infarction, and diabetes. In addition, information was taken from the patients’ hospital charts. In all patients active follow-up was conducted 1, 3, 4, 5, 6, 8 and 10 years after discharge from the rehabilitation center. Information was obtained from the patients using a mailed standardized questionnaire. Information regarding secondary CVD events and treatment since discharge from the in-hospital rehabilitation clinic was 4
ACCEPTED MANUSCRIPT obtained from the primary care physicians also by means of a standardized questionnaire. If a participant had died during follow-up, the death certificate was obtained from the local Public Health Department and the main cause of death was coded according to the International Classification of Diseases (ICD-9 pos. 390-459: ICD-10 pos. I0-I99 and R57.0). Secondary CVD events were defined either as CVD as the main cause of death (as stated in the death certificate), non-fatal myocardial
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infarction (MI), or non-fatal stroke. All non-fatal secondary events were reported by the primary care physicians. Laboratory methods
43
days
after
the
acute
event;
1st
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Blood at baseline was drawn at discharge from the rehabilitation centre (on average quartile
36
days,
3rd
quartile
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51 days) in a fasting state under standardized conditions and stored at -80°C until analysis. IgM anti-PC measurements by enzyme-linked immunosorbent assay using the CVDefine kit (Athera Biotechnologies, Solna, Sweden). This assay employs an immobilized, conjugated PC antigen, and human anti-PC IgM for standards (11). All cTnT measurements were performed by a high-sensitivity (hs) assay (Roche Diagnostics, Penzberg, Germany) on an Elecsys 2010 platform. A value of 14 ng/L
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has been reported to represent the 99th percentile in a healthy reference population (12). The inter-assay coefficients of variation were 3.6% and 2.9% at concentrations of 42 and 2.82 ng/L. C-reactive protein (CRP) concentrations were measured by latex-enhanced immunonephelometry on a Behring Nephelometer II (N Latex CRP
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mono Dade-Behring). Cystatin C was determined on the same device (DadeBehring) (13). NT-proBNP was measured by electrochemiluminescence on an
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Elecsys 170 (Roche Diagnostics) (14). Lipoprotein-associated phospholipase A2 (LpPLA2) and secretory phospholipase A2 (sPLA2) mass and activity were determined as reported previously (15,16). Inter-assay coefficients of variation (CVs) were 4.1% for hsCRP, 3.8% for
cystatin C, between 3% (for a target value 4970 pg/ml) and 7% (for a target value 178 pg/ml) for NT-proBNP. All markers were measured in a blinded fashion. Creatinine, blood lipids and leukocyte count were determined by routine methods in both participating hospitals.
5
ACCEPTED MANUSCRIPT Statistical methods The study population has been described with respect to various sociodemographic and clinical characteristics. The associations of sociodemographic characteristics, various cardiovascular risk factors, and medication with IgM-anti PC concentrations were quantified by means of the non-parametric Kruskal-Wallis test. Partial
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Spearman correlation coefficients, adjusted for age and gender, were calculated for hs-cTnT concentrations and blood lipids, hsCRP, creatinine, cystatin C, NT-proBNP, as well as Lp-PLA2 and sPLA2.
The relation of IgM-anti PC concentrations with adverse CVD events during follow-up was assessed by the Kaplan-Meier and life table method and quantified by
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means of the log-rank test. Then, Cox proportional hazards regression analysis was employed to assess the independent association of IgM-anti PC concentration with
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the risk of secondary CVD events (hazard ratios, HR, and their 95% confidence intervals, CI). A basic model was adjusted for age (years) and gender. In a second step, potential confounding variables were added in the model to the main factor IgM anti-PC and the variables age and gender. The following potential confounders were considered in multivariable analyses: body mass index (BMI, kg/m2), smoking status (never, current, former-smoker) duration of school education (< 10 years, ≥10 years),
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hospital site (Isny, Bad Nauheim), marital status (married, other), history of MI (yes, no), history of hypertension (yes, no), history of diabetes mellitus (yes, no), severity of CHD (number of affected epicardial coronary vessels at baseline), initial
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management of CHD (conservative, percutaneous coronary intervention, PCI, coronary artery bypass grafting, CABG), intake of ß-blockers (yes, no), intake of ACE-inhibitors (yes, no), intake of diuretics (yes, no), intake of lipid-lowering drugs
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(yes, no), intake of anti-diabetic drugs (yes, no), intake of anti-hypertensive drugs (yes, no), intake of anti-platelet drugs (yes, no), HDL-cholesterol (mg/dl), LDLcholesterol (mg/dl). To avoid overadjustment, only those variables were added to the model which were significant predictors of a secondary event at an α-level of 0.1 or which changed the parameter estimates for the main variables (IgM-anti PC) by more than 10%. A final modelling step was performed to adjust for biomarkers related to IgM-anti PC (i.e. hs-TnT, cystatin C, and NT-proBNP). In addition, we also used a spline regression (with 4 degrees of freedom) for multivariate analysis. All statistical procedures were performed with the SAS statistical software package (release 8.2 SAS Institute Inc. ).
6
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Results The main sociodemographic, clinical and laboratory characteristics of the 1,062 patients with clinically manifest CHD are shown in Table 1. The mean age of these CHD patients (84.9% men) was 58.9 years. About two third (58.5%) had a history of myocardial infarction with 12.7% reporting symptomatic heart failure. Body mass index was 26.9 kg/m² and 17.0% were diabetic. Mean GRACE Score was 96.1 (SD
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20.8). The majority of patients had a normal renal function according to creatinine and serum concentrations of cystatin C. Median serum concentrations of IgM anti-PC were 49.2 U/ml. Cut point for the lowest 10% of the distribution of IgM anti-PC was <21.3 U/ml.
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As depicted in Table 2 median IgM anti-PC concentrations were significantly lower among males, although the proportion in the <10th percentile was similar
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among men and women. Median IgM anti-PC in men was lower also in the highest age category, never smokers, and among patients with history of hypertension. Furthermore, we found lower median concentrations with increasing extension of CAD with respect to number of vessels affected. Remarkably, patients with a history of acute myocardial infarction (MI) showed higher concentrations of IgM anti-PC compared to those without and a conservative initial management strategy in the
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acute situation was associated with substantially higher IgM anti-PC titers compared to a interventional or a surgical strategy. Use of lipid-lowering agents was also associated with higher serum concentrations of IgM anti-PC whereas history of
PC. (Table 2)
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diabetes and intake of anti-diabetic medication were associated with lower IgM anti-
As shown in Table 3 we found no substantial association between IgM anti-PC
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serum concentration and lipids, markers of renal function and all other biomarkers measured including markers of inflammation, heart failure and hs-troponin T after adjustment for age and gender. A weak positive correlation was found with hstroponin I
As depicted in Figure 1, comparing recurrent fatal and non-fatal CVD events
did not show a difference between IgM anti-PC concentrations. However, when looking closer to the lower end of the distribution, those in the lowest 10% of the IgM anti-PC distribution showed a significantly increased risk of adverse cardiovascular events during follow-up with an incidence of 38.3 per 1000 patient years within the latter group (p-value of log-rank test = 0.02).
7
ACCEPTED MANUSCRIPT Table 4 then shows the results after multivariable adjustment for covariates. No association was found if the hazard associated with IgM anti-PC was investigated in quartiles. However, if the bottom quartile was split into two categories, subjects in the lowest 10% (i.e. <21.3 U/ml) of the IgM anti-PC distribution showed a hazard ratio (HR) of 1.60 (95% confidence interval (CI) 1.01-2.55). After adjustment for further covariates the HR increased to 1.75 (95% CI 1.07-2.84) and was even increased to
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an HR of 1.94 (95% CI 1.18-3.18) after additional adjustment for cystatin C, NTproBNP and hs-troponin T. (CRP was neither related to IgM anti-PC nor to adverse CVD events – latter data not shown).
Figure. 2 shows splines representing IgM anti-PC associated with hazard for
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adverse CVD events after adjustment for covariates indicating that only very low IgM
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anti-PC concentrations are associated with increased risk for recurrent events.
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Discussion In this observational prospective study with long-term follow-up in more than 1000 patients with stable CHD at baseline we measured natural antibodies against phosphorylcholine (IgM anti-PC) and found an increased risk for recurrent CV events in patients in the very low end of the distribution, which persisted after adjustment for
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a variety of traditional and emerging CVD risk factors as well as markers of left ventricular and renal function, and cardiac damage.
Natural antibodies against phosphorylcholine (IgM anti-PC) seem to be crucial in the elimination of pro-inflammatory oxidized phospholipids (oxPLs) and apoptotic
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cells (17) and thus showing anti-atherogenic properties. Elevated IgM anti-PC concentrations have been proven beneficial in animal models of vascular disease
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potentially by inhibiting the uptake of ox-LDL into macrophages (18,19). In contrast, low concentrations of IgM anti-PC indicate a reduced defence mechanism and may be associated with accelerated atherosclerosis including increased risk of acute cardiovascular events (6).
We could demonstrate a significant and independent association between very low concentrations of IgM anti-PC antibodies and long-term increased risk of future
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fatal and non-fatal cardiovascular events among patients in the stable phase of CAD. Prior studies have shown conflicting results on the association between IgM anti-PC antibodies and risk of future cardiovascular events in various populations. Among patients with hypertension, after suffering from stroke, patients on chronic dialysis
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and after recent MI low concentrations of IgM anti-PC were predictive for cardiovascular events (4,7,8,11,20). Moreover, in a small study of fifty-six patients
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with severe peripheral artery disease (PAD) after surgical revascularisation concentrations of IgM anti-PC in the lowest quartile of the distribution were associated with statistically significant worse bypass graft patency (21). In the PRACSIS registry (Prognosis and Risk in Acute Coronary Syndrome in Schweden, 1995-2001) low levels of IgM anti-PC titers were found to be independently associated with a composite of major cardiac events and all-cause mortality during short (6 months), intermediate (18 months) and long-term (72 months) follow-up. This held true even when comparing those patients below median concentrations with those showing levels above the median. Only for the endpoint mortality after 72 months the hazard ratio lost its statistical significance (6).
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ACCEPTED MANUSCRIPT However, in the large prospective ATLAS ACS-TIMI 46 Trial, a multicenter, multinational dose ranging trial of rivaroxaban including 3,491 patients with ACS, Geller et al. neither found an association between IgM anti-PC concentrations and future cardiovascular events nor with mortality (10). Although the authors compared risk for the defined endpoints according to the quartiles of distribution and using a cut-point of 17 U/ml for further analyses as suggested in other studies they found no
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association. Very recently, Gimenez et al. also reported no association between IgM anti-PC and major adverse cardiovascular events (MACE) in a prospective study including 1072 patients with NSTEMI. Longest follow-up in this study was 12 months and a pre-defined cut-off of <29 U/ml was used to identify patients at risk (22). This is
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quite consistent with our findings where the lowest quartile of the IgM anti-PC distribution (cut-off <31.2U/ml) also was not associated with future recurrent CVD
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events. However, we found a strong and independent association with CVD events and mortality among those with very low concentrations of IgM anti-PC (<21.3 U/L i.e. lowest 10% of the distribution). In addition, follow-up was 6 months in the ATLAS ACS-TIMI 46 Trial and up to 12 months in the study reported by Gimenez et al. and thus substantially shorter compared to our study. Also the number of events in these studies was much smaller.
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Although these results are somewhat conflicting, the majority of data reported so far suggest that subjects with low concentrations of IgM anti-PC are at increased risk for future cardiovascular events. However, future studies are needed focusing on individuals with very low IgM anti-PC titers and with respect to intra-individual
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variations of anti-PC concentrations over time to evaluate the potential of therapeutical interventions initiated in these patients. Nevertheless, there are data
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showing that IgM anti-PC concentrations are relatively stable over time (23). Our study has several strengths but also limitations which should be
considered. The large sample size of well defined patients with stable CAD and longterm follow up are important strengths of the present study. However, using only one time-point of IgM anti-PC at baseline we were not able to analyse risk over time according to intra-individual variation. In addition, using a very low cut-point in a secondary analysis approach reduced numbers of individuals in the analysed subgroups and thus increased the risk of chance findings. Therefore, these results need to be replicated in similar large patient populations. Future studies should explore whether besides identifying patients at high risk for future adverse CVD events IgM anti-PC might present a new therapeutic target in 10
ACCEPTED MANUSCRIPT this albeit relatively small group of patients with very low concentrations of this molecule. In conclusion, in patients with stable CAD very low concentrations of IgM-antiPC are associated with increased risk for recurrent fatal and non-fatal future CVD events. If corroborated in future studies, IgM anti-PC concentrations may add prognostic information in addition to traditional and emerging cardiovascular risk
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markers among these patients and thus may improve risk stratification in the future.
Funding: Funding was received from the German Federal Ministry of Education and
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Research (01GD9820/0 and 01ER0814) and the Pitzer Foundation, Bad Nauheim, Germany. The funders played no role in design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or
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approval of the manuscript.
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References 1. Libby P, Hansson GK. Inflammation and immunity in diseases of the arterial tree: players and layers. Circ
Res.
2015
Jan
16;116(2):307-11.
doi:
10.1161/CIRCRESAHA.116.301313.
RI PT
2. Chou MY, Fogelstrand L, Hartvigsen K, Hansen LF, Woelkers D, Shaw PX, Choi J, Perkmann T, Bäckhed F, Miller YI, Hörkkö S, Corr M, Witztum JL, Binder CJ.
Oxidation-specific epitopes are dominant targets of innate natural antibodies in mice and humans.
SC
J Clin Invest. 2009 May;119(5):1335-49. doi: 10.1172/JCI36800. 3. Frostegård J, Huang YH, Rönnelid J, Schäfer-Elinder L.
common mechanism.
M AN U
Platelet-activating factor and oxidized LDL induce immune activation by a
Arterioscler Thromb Vasc Biol. 1997 May;17(5):963-8. 4. de Faire U, Su J, Hua X, Frostegård A, Halldin M, Hellenius ML, Wikström M, Dahlbom I, Grönlund H, Frostegård J.
Low levels of IgM antibodies to phosphorylcholine predict cardiovascular
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disease in 60-year old men: effects on uptake of oxidized LDL in macrophages as a potential mechanism.
J Autoimmun. 2010 Mar;34(2):73-9. doi: 10.1016/j.jaut.2009.05.003.
JL.
EP
5. Binder CJ, Chang MK, Shaw PX, Miller YI, Hartvigsen K, Dewan A, Witztum
Innate and acquired immunity in atherogenesis.
AC C
Nat Med. 2002 Nov;8(11):1218-26.
6. Caidahl K, Hartford M, Karlsson T, Herlitz J, Pettersson K, de Faire U, Frostegård J.
IgM-phosphorylcholine autoantibodies and outcome in acute coronary syndromes. Int J Cardiol. 2013 Jul 31;167(2):464-9. doi: 10.1016/j.ijcard.2012.01.018.
7. Fiskesund R, Stegmayr B, Hallmans G, Vikström M, Weinehall L, de Faire U, Frostegård J. Low levels of antibodies against phosphorylcholine predict development of stroke in a population-based study from northern Sweden. Stroke. 2010 Apr;41(4):607-12. doi: 10.1161/STROKEAHA.109.558742. 12
ACCEPTED MANUSCRIPT 8. Su J, Georgiades A, Wu R, Thulin T, de Faire U, Frostegård J. Antibodies of IgM subclass to phosphorylcholine and oxidized LDL are protective factors for atherosclerosis in patients with hypertension. Atherosclerosis. 2006 Sep;188(1):160-6. 9. Carrero JJ, Hua X, Stenvinkel P, Qureshi AR, Heimbürger O, Bárány P, Lindholm B, Frostegård J.
RI PT
Low levels of IgM antibodies against phosphorylcholine-A increase mortality risk in patients undergoing haemodialysis.
Nephrol Dial Transplant. 2009 Nov;24(11):3454-60. doi: 10.1093/ndt/gfp309. 10. Geller BJ, Mega JL, Morrow DA, Guo J, Hoffman EB, Gibson CM, Ruff CT.
SC
Autoantibodies to phosphorylcholine and cardiovascular outcomes in patients with acute coronary syndromes in the ATLAS ACS-TIMI 46 trial.
0968-y.
M AN U
J Thromb Thrombolysis. 2014 Apr;37(3):310-6. doi: 10.1007/s11239-013-
11. Sjöberg BG, Su J, Dahlbom I, Grönlund H, Wikström M, Hedblad B, Berglund G, de Faire U, Frostegård J.
Low levels of IgM antibodies against phosphorylcholine-A potential risk marker for ischemic stroke in men.
07.009.
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Atherosclerosis. 2009 Apr;203(2):528-32) doi: 10.1016/j.atherosclerosis.2008.
12. Giannitsis E, Kurz K, Hallermayer K, Jarausch J, Jaffe AS, Katus HA. Analytical validation of a high-sensitivity cardiac troponin T assay.
EP
Clin Chem. 2010 Feb;56(2):254-61. doi: 10.1373/clinchem.2009.132654. 13. Koenig W, Twardella D, Brenner H, Rothenbacher D.
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Plasma concentrations of cystatin C in patients with coronary heart disease and risk for secondary cardiovascular events: more than simply a marker of glomerular filtration rate. Clin Chem. 2005 Feb;51(2):321-7.
14. Rothenbacher D, Koenig W, Brenner H. Comparison of N-terminal pro-B-natriuretic peptide, C-reactive protein, and creatinine clearance for prognosis in patients with known coronary heart disease. Arch Intern Med. 2006 Dec 11-25;166(22):2455-60. 15. Koenig W, Twardella D, Brenner H, Rothenbacher D.
13
ACCEPTED MANUSCRIPT Lipoprotein-associated phospholipase A2 predicts future cardiovascular events in patients with coronary heart disease independently of traditional risk factors, markers of inflammation, renal function, and hemodynamic stress. Arterioscler Thromb Vasc Biol. 2006 Jul;26(7):1586-93. 16. Koenig W, Vossen CY, Mallat Z, Brenner H, Benessiano J, Rothenbacher D. Association
between
type
II
secretory
phospholipase
A2
plasma
RI PT
concentrations and activity and cardiovascular events in patients with coronary heart disease.
Eur Heart J. 2009 Nov;30(22):2742-8. doi: 10.1093/eurheartj/ehp302.
Witztum JL.
SC
17. Shaw PX, Hörkkö S, Chang MK, Curtiss LK, Palinski W, Silverman GJ,
Natural antibodies with the T15 idiotype may act in atherosclerosis, apoptotic
M AN U
clearance, and protective immunity. J Clin Invest. 2000 Jun;105(12):1731-40.
18. Caligiuri G, Khallou-Laschet J, Vandaele M, Gaston AT, Delignat S, Mandet C, Kohler HV, Kaveri SV, Nicoletti A.
Phosphorylcholine-targeting immunization reduces atherosclerosis. J Am Coll Cardiol. 2007 Aug 7;50(6):540-6.
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19. Faria-Neto JR, Chyu KY, Li X, Dimayuga PC, Ferreira C, Yano J, Cercek B, Shah PK. Passive
immunization
phosphorylcholine
with
reduces
monoclonal
accelerated
IgM
vein
antibodies
graft
against
atherosclerosis
in
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apolipoprotein E-null mice. Atherosclerosis. 2006 Nov;189(1):83-90.
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20. Grönlund H, Hallmans G, Jansson JH, Boman K, Wikström M, de Faire U, Frostegård J.
Low levels of IgM antibodies against phosphorylcholine predict development of acute myocardial infarction in a population-based cohort from northern Sweden. Eur
J
Cardiovasc
Prev
Rehabil.
2009
Jun;16(3):382-6.
doi:
10.1097/HJR.0b013e32832a05df. 21. Sobel M, Moreno KI, Yagi M, Kohler TR, Tang GL, Clowes AW, Zhou XH, Eugenio E. Low levels of a natural IgM antibody are associated with vein graft stenosis and failure. 14
ACCEPTED MANUSCRIPT J Vasc Surg. 2013 Oct;58(4):997-1005.e1-2. doi: 10.1016/j.jvs.2013.04.042. 22. Rubini Gimenez M, Pagano S, Virzi J, Montecucco F, Twerenbold R, Reichlin T, Wildi K, Grueter D, Jaeger C, Haaf P, Vuilleumier N, Mueller C. Diagnostic and prognostic value of autoantibodies anti-apolipoprotein A-1 and anti-phosphorylcholine in acute non-ST elevation myocardial infarction. Eur J Clin Invest. 2015 Apr;45(4):369-79. doi: 10.1111/eci.12411.
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23. Fiskesund R, Su J, Bulatovic I, Vikström M, de Faire U, Frostegård J.
IgM phosphorylcholine antibodies inhibit cell death and constitute a strong protection marker for atherosclerosis development, particularly in combination with other auto-antibodies against modified LDL.
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Results Immunol. 2012 Jan 8;2:13-8. doi: 10.1016/j.rinim.2012.01.001.
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eCollection 2012.
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ACCEPTED MANUSCRIPT Table 1. Sociodemographic, clinical, and laboratory characteristics in 1,062 patients with clinically manifest coronary heart disease
Age (years) (µ, SD)
58.9 ± 8.0
Men, n (%)
902 (84.9%)
History of myocardial infarction, n (%)
621 (58.5%)
History of heart failure, n (%)
131 (12.7%)
Clinical score (angiographic evaluation) 258 (24.3%)
- 2 vessel disease
282 (26.6%)
- 3 vessel disease
455 (42.8%)
- unknown
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- 1 vessel disease
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Characteristics at Baseline
52 (4.9%)
School education <10 yr, n (%) Body mass index (kg/m2), (µ, SD)
GRACE Score (µ, SD)
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History of diabetes, n (%)
637 (60.0%) 26.9 ± 3.2
181 (17.0%) 96.1 (20.8) 169.1 (32.8)
LDL-cholesterol (mg/dl) (µ, SD)
101.1 (29.6)
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Total cholesterol (mg/dl) (µ, SD)
39.4 (10.5)
C-reactive protein (mg/L) *
3.51 (1.26; 8.40)
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HDL-cholesterol (mg/dl) (µ, SD)
Cystatin C (mg/L)*
1.03 (0.93; 1.19)
NT-proBNP (pg/mL)*
568.85 (277.60; 1101.00)
hs-troponin T* (ng/L)
13.9 (8.9-21.9)
hs-troponin I * (pg/mL)
14.3 (9.4-23.8)
MR-proANP* (pmol/L)
135.4 (95.2;185.9)
IgM-antiPC* (U/ml)
49.2 (31.2;77.7)
* median, 25th and 75th quantile cut-point
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ACCEPTED MANUSCRIPT Table 2. IgM-antiPC distribution (Median) and in lower 10 percentile according to various sociodemographic characteristics, cardiovascular risk factors, and ECG findings IgM-antiPC Distribution Median
School education
- Female
160
56.1
- Male
902
48.2
- 30-39
24
68.7
8.3%
- 40-49
130
62.3
6.2%
- 50-59
307
54.9
- 60-70
601
43.6
- < 10 yrs. 637
51.7
- ≥ 10 yrs. 425
Body mass index 2
(kg/m )
- Married
881
- Other
181
- < 25
294
- 25-30
603
- >30 Smoking status
51.2
0.03
9.8%
<0.0001
12.5%
0.07
10.8%
0.72
8.8%
10.1%
49.8
- Never
334
41.9
17.4%
- Ex
676
53.0
6.2%
52
54.1
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50.6
- Yes
621
51.9
- No
441
44.2
History of
- Yes
589
45.4
hypertension
- No
473
54.1
History of heart
- Yes
131
45.4
failure
- No
897
49.3
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881
0.40
10.1%
49.3
- No
0.014
9.3%
8.2%
43.6
0.73
6.5%
47.6
181
p-value**
10.6%
49.0
- Yes
History of MI
<10th percentile
161
- Current History of diabetes
46.4
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Family status
p-value*
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(U/ML)
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Age (years)
N
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Gender
Proportion in
0.88
<0.0001
12.4%
9.6%
0.60
0.34
<0.0001
11.6% 0.06
9.5%
0.40
8.9% 0.002
11.3%
0.18
10.7% 0.001
8.9%
0.32
13.0% 0.30
9.1%
0.16
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(U/ml)
Proportion in p-value* <10th percentile p-value**
- Zero/one
273
52.4
9.2%
(number of affected
- Two
282
51.2
9.2%
vessels)
- Three
455
46.0
Initial management of - Conservative
192
55.9
CHD
- PCI
363
50.6
- CABG
507
44.3
Left ventricular
- No/only little
757
49.3
function*
- Modest/severe
218
50.5
(degree of impairment)
- Unknown
87
46.8
Intake of lipid-
- Yes
818
51.2
lowering agent
- No
242
45.0
154
43.0
906
50.1
0.03
drugs
- No
Intake of anti-
- Yes
hypertensive drugs
- No
28
Intake of anti-platelet
- Yes
1040 49.0
drugs
- No
20
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62.5
0.57
9.4%
11.4%
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0.001
0.17
10.3% 8.7%
0.96
0.05
0.05
1032 49.5 45.6
11.2%
6.8%
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Intake of anti-diabetic - Yes
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Angiographic score
0.81
9.2%
0.77
8.8% 13.6%
0.03
12.3% 9.5%
0.27
10.1% 3.6%
0.26
9.8% 0.55
15.0%
0.44
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*Kruskal-Wallis Test, **Chi-Square Test
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ACCEPTED MANUSCRIPT Table 3. Partial Spearman rank correlation coefficients (R) between established and emerging risk factors of coronary heart disease (age and gender adjusted). IgM-antiPC p-value
HDL cholesterol [mmol/L]
-0.05
0.10
Total cholesterol [mmol/L]
0.05
0.13
LDL cholesterol [mmol/L]
0.04
0.17
Leukocytes [G/L]
0.04
0.23
C-reactive protein [mg/L]
0.03
Interleukin-6 [pg/mL]
0.0006
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R
0.27
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1.00
Adiponectin [µg/ml]
-0.01
0.74
0.06
0.06
0.06
0.05
0.001
0.96
0.02
0.42
-0.01
0.74
0.08
0.01
0.05
0.07
0.04
0.22
ICAM [nmol]
-0.02
0.51
MR-proANP (pmol/L)
0.03
0.29
GDF 15 [pg/mL]
0.02
0.61
sST2 [ng/mL]
0.05
0.11
Cystatin C [mg/L] NT-proBNP [pg/mL]
Creatinine [µmol/] Hs-Troponin T [ng/L]
HbA1c (%)
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sPLA2 [ng/mL]
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Hs-Troponin I [pg/mL]
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Lp-PLA2 mass [ng/mL]
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ACCEPTED MANUSCRIPT Table 4: Association of IgM-antiPC with fatal and non-fatal cardiovascular events during follow-up Results of Multivariable Analysis HR (95 % CI)
Adjusted for age
*Adjusted for multiple **Adjusted for
and gender
covariates
Top Quartile
1 referent
1 referent
Third
1.18 (0.80-1.75)
1.14 (0.76-1.70)
1.26 (0.84-1.91)
Second
1.01 (0.67-1.51)
1.03 (0.68-1.56)
1.12 (0.73-1.72)
Bottom Quartile
1.00 (0.67-1.50)
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p for trend: 0.78
multiple covariates
1 referent
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IgM-antiPC
HR (95 % CI)
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HR (95 % CI)
1.14 (0.74-1.74)
p for trend: 0.84
p for trend: 0.72
25%-10%
0.64 (0.38-1.09)
0.61 (0.35-1.05)
0.69 (0.40-1.22)
<10% ***
1.60 (1.01-2.55)
1.75 (1.07-2.84)
1.94 (1.18-3.18)
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* adjusted for age, gender, rehabilitation clinic, history of diabetes mellitus, smoking status, PCI, CABG, HDL-cholesterol, LDL-cholesterol, intake of lipid-lowering drugs, intake of anti-diabetic drugs, intake of anti-hypertensive drugs **adjusted for all covariates above and (log-transformed concentrations) of cystatin C, Nt-proBNP and hs-TNI.
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*** bottom quartile splitted in two categories: 25%-10% and <10%
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ACCEPTED MANUSCRIPT Figure 1: Kaplan-Meier estimates of secondary fatal and non-fatal CVD events
1000 937
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500 966
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Follow-up time Persons under risk
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during follow-up (time=years) according to quartiles of IgM-antiPC
1500 895
2000 838
2500 767
Fatal and non-fatal CVD event during follow-up, N (Incidence*) 46 (21.2)
3000 691
IgM-antiPC
N
>77.66 (top quartile)
265
>49.16 – 77.66
266
55 (26.2)
>31.20 – 49.16
264
50 (23.3)
<31.20 (bottom quartile)
267
50 (24.0)
0.73
20 (15.4) 30 (38.3) 201 (23.7)
0.02
>21.30 – 31.20 *** <21.30
160 107 1,062
3500 614
p-Value**
* per 1,000 patient years ** Log Rank Test *** Bottom quartile splitted in two categories: 25%-10% and <10% 1
ACCEPTED MANUSCRIPT Fig. 2: Splines representing IgM-antiPC associated with hazard for adverse
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CVD events after adjustment for covariates
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ACCEPTED MANUSCRIPT Highlights
Low concentrations of IgM phosphorylcholine autoantibodies (IgM anti-PC), are involved in inflammation and predict risk for recurrent events in ACS patients
•
The predictive value of IgM anti-PC for long-term prognosis in stable CHD patients is largely unknown
•
In 1,062 patients with stable CHD very low levels of IgM anti-PC were associated with increased risk for future coronary events
•
IgM anti-PC may add prognostic information to traditional risk factors
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•