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Utility of serum IgG, IgG4 and carbonic anhydrase II antibodies in distinguishing autoimmune pancreatitis from pancreatic cancer and chronic pancreatitis
Advances in Medical Sciences 59 (2014) 288–292
Contents lists available at ScienceDirect
Advances in Medical Sciences journal homepage: www.elsevier.com/locate/advms
Original Research Article
Utility of serum IgG, IgG4 and carbonic anhydrase II antibodies in distinguishing autoimmune pancreatitis from pancreatic cancer and chronic pancreatitis Renata Talar-Wojnarowska a,*, Anita Ga˛siorowska a, Marek Olakowski b, Daria Dranka-Bojarowska b, Paweł Lampe b, Jacek S´migielski d, Magdalena Kujawiak c, Janina Grzegorczyk c, Ewa Małecka-Panas a a
Department of Digestive Tract Diseases, Medical University of Lodz, Poland Department of Digestive Tract Surgery, Silesian Medical University, Katowice, Poland c Department of Microbiology and Laboratory Medical Immunology, Faculty of Medicine, Medical University of Lodz, Poland d Department of Thoracic Surgery, General and Oncological Surgery, Medical University of Lodz, Poland b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 18 May 2014 Accepted 12 August 2014 Available online 26 August 2014
Purpose: Autoimmune pancreatitis (AIP) can mimic pancreatic cancer in its clinical presentation, imaging features and laboratory parameters. The aim of our study was to compare IgG, IgG4 and antiCAIIAb serum levels in patients with AIP, pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP) and to assess their clinical significance and utility in differential diagnosis of pancreatic diseases. Patient/methods: The study included 124 patients: 45 with PA, 24 with AIP and 55 with CP. Peripheral venous blood samples were obtained from all analyzed patients at the time of hospital admission and total IgG, IgG4 and anti-CAIIAB serum levels were measured using ELISA tests. Results: Serum levels of IgG, IgG4 and anti-CAIIAb were significantly higher in patients with AIP compared to PA and CP patients (p < 0.001). In AIP patients the median IgG levels were 19.7 g/l, IgG4 levels – 301.9 mg/dl and anti-CAIIAb – 81.82 ng/ml, compared to 10.61 g/l, 123.2 mg/dl and 28.6 ng/ml, respectively, in PA patients. IgG4 for the cut-off 210 mg/dl showed the best sensitivity and specificity (83.8% and 89.5%) in AIP diagnosis compared to IgG (69.3% and 87.3%, respectively) and anti-CAIIAb (45.3% and 74.3%). However, 16 (35.5%) patients with PA and 14 (25.4%) patients with CP had IgG4 levels greater than 140 mg/dl. Moreover, in 3 (6.67%) patients with pancreatic cancer those values were greater than 280 mg/dl. No patients with CP had IgG4 more than 280 mg/dl. Conclusions: IgG4 at cut-off 210 mg/dl showed the best sensitivity and specificity in AIP diagnosis compared to IgG and anti-CAIIAb, however elevations of serum IgG4 may be seen in subjects without AIP, including pancreatic cancer. ß 2014 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
Keywords: Autoimmune pancreatitis Pancreatic adenocarcinoma Chronic pancreatitis IgG4 IgG Carbonic anhydrase II (CAII)
1. Introduction Autoimmune pancreatitis (AIP) is a distinct form of pancreatitis characterized clinically by frequent presentation with obstructive jaundice with or without a pancreatic mass. AIP can mimic pancreatic cancer in its clinical presentation, imaging features and laboratory parameters [1,2]. The diagnosis of AIP remains a
* Corresponding author at: Department of Digestive Tract Diseases, Medical University of Lodz, Kopcinskiego 22, 90-153 Lodz, Poland. Tel.: +48 42 678 64 80; fax: +48 42 678 64 80. E-mail address: [email protected] (R. Talar-Wojnarowska).
challenging test for clinicians. Due to clinical and radiological similarities but a completely different prognosis and therapy, it is of fundamental importance to differentiate between pancreatic cancer and autoimmune pancreatitis. The method of choice for AIP treatment is steroid therapy being clinically, morphologically, and serologically effective in AIP patients. However, steroid treatment should be started after negative evaluation for pancreatic cancer [3,4]. It is known that there are two clinicopathologically different types of autoimmune pancreatitis: more frequent type-1 AIP, called lymphoplasmacytic sclerosing pancreatitis (LPSP) and type 2 characterized by neutrophilic infiltration in the epithelium of the pancreatic duct. In general, the most common clinical features of
http://dx.doi.org/10.1016/j.advms.2014.08.003 1896-1126/ß 2014 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
R. Talar-Wojnarowska et al. / Advances in Medical Sciences 59 (2014) 288–292
type-1 of AIP are weight loss and painless jaundice, the last being reported to occur in up to 100% of patients. Type-2 AIP patients are younger, more likely have acute pancreatitis or ulcerative colitis, and rarely show elevation of serum IgG4 compared with type-1 AIP patients [5]. As it is sometimes difficult to obtain adequate biopsy material from the pancreas, AIP is currently diagnosed based on careful consideration of a combination of characteristic clinical, serological, morphological, and histopathological features [4,6]. High serum IgG4 concentrations have been observed in 90% of patients with AIP, less frequent in patients with pancreatic cancer, chronic pancreatitis, primary biliary cirrhosis and primary sclerosing cholangitis. Serum IgG4 concentration is therefore considered a reliable marker for the diagnosis of AIP and has been included in various diagnostic criteria. Moreover, increased levels of serum antibodies, including antibodies against carbonic anhydrase II (CAII), have been reported in AIP [7,8]. Carbonic anhydrase is a zinc metalloenzyme of cytoplasmatic location. There are at least twelve CA isoenzymes with CAII expressed in the ductal epithelial cells of several exocrine glands, including pancreas, salivary gland, kidney and liver (bile ducts). Anti-CAII antibodies (anti-CAIIAb) were described as a serological marker not only for AIP, but also for autoimmune hepatitis, Sjo¨gren syndrome, systemic lupus erythematosus, polymyositis and dermatomyositis [9,10]. The aim of our study was to compare IgG, IgG4 and anti-CAIIAb serum levels in patients with AIP type-1, pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP) and to assess their clinical significance and utility in differential diagnosis of pancreatic diseases.
2. Patients and methods
289
pancreatic duct and its branches shown by ultrasound, computed tomography or endoscopic retrograde pancreatography or histologically proven CP. Alcoholic CP was diagnosed in patients who consumed more than 80 g/day of alcohol (males) and at least 40 g/ day of alcohol (females) for 5 or more years, before the first symptoms of the disease. The associations of the IgG, IgG4, and anti-CAIIAb and clinical data at diagnosis have been evaluated. The following clinical variables were analyzed: age and sex of patients, presence of jaundice, diabetes mellitus, weight loss >10% and prior episodes of acute pancreatitis. In patients with PA additionally tumor size, histological grade, lymph node involvement and distant metastases were analyzed. 2.2. Methods Peripheral venous blood samples were obtained from all analyzed patients at the time of hospital admission. Total IgG serum level was measured using specific enzyme-linked immunosorbent assay (ELISA) (Immunodiagnostik AG, Bensheim, Germany) in accordance with the test procedure. Results were expressed in g/l. The detection limit was 1.9 ng/ml. There was no cross reactivity with other serum proteins. The serum concentrations of IgG4 and anti-CAIIAb were measured with ELISA according to the producer recommendations (Uscn Life Science Inc., Wuhan, China). Results were expressed in mg/dl for IgG4 and in ng/ml for anti-CAIIAb. The sensitivity of the immunoassays was as follows: 45.7 ng/ml for IgG4 and 0.093 ng/ ml for anti-CAIIAb. There were no significant cross-reactions or interferences between human IgG4 or anti-CAIIAb and analogs. Normal values for analyzed parameters were previously assessed as 8–16 g/l for IgG, 8–140 ng/ml for IgG4 and 0–31 ng/ml for antiCAIIAb.
2.1. Patients 2.3. Statistical analysis The study included 124 patients: 45 with PA (27 men and 18 women aged 49–83), 24 with AIP type-1 (11 men and 13 women aged 42–71) and 55 with CP (36 men and 19 women, aged 27–73). The written informed consent was obtained from all the patients. The study protocol was approved by the ethical committee of Lodz Medical University. In all patients with pancreatic adenocarcinoma the diagnosis was confirmed with pathology of surgical specimen (39 patients) or pancreatic tissue biopsy (6 patients). The diagnosis of AIP type-1 was established according to the International Consensus Diagnostic Criteria (ICDC) based to the pancreatic histology and/or imaging, serology, other organ involvement and response to steroid treatment (6). Patients with AIP had no obvious cause of CP, such as alcoholism, gallstones, hypercalcaemia or other identifiable etiologic factors. The diagnosis of CP was determined by histology and/or standard imaging criteria and clinical course. The diagnosis of CP was based on the following findings: calcifications, pancreatic stones, dilatation, stenosis, or cyst formation of the main
Statistical analysis comprised arithmetical mean and standard deviation. To determine differences between groups Kruskal– Wallis test and Fisher’s exact test were used. p-Values <0.05 were considered to be significant. Receiver operating characteristic (ROC) curves depicting the ability to discriminate between AIP, PA and CP were plotted for each of the markers.
3. Results In our study there was no statistically significant differences in clinical features between patients with PA and AIP, what is shown in Table 1. Patients with CP were significantly younger and were less likely to have jaundice (Table 1). Only 20.8% patients with AIP as well as 26.6% with CP and 15.5% with PA had a prior episode of acute pancreatitis (p > 0.05). Serum levels of IgG, IgG4 and anti-CAIIAb were significantly higher in patients with autoimmune pancreatitis compared to PA
Table 1 Comparison of clinical features in patients with autoimmune pancreatitis (AIP), pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP). Clinical features
PA (n = 45)
AIP (n = 24)
CP (n = 55)
p
Age Sex (F/M) Diabetes mellitus Jaundice Weight loss >10% Acute pancreatitis
71 3.9 23/22 33% (15/45) 55.5% (25/45) 42.2% (19/45) 15.5% (7/45)
64 4.5 15/9 41.6% (10/24) 45.8% (11/24) 29.2% (7/24) 20.8% (5/24)
49 5.7 35/20 30.9% (17/55) 18.2% (10/55) 32.7% (18/55) 26.6% (12/45)
0.01* NS NS 0.01* NS NS
*
CP vs PA and AIP.
R. Talar-Wojnarowska et al. / Advances in Medical Sciences 59 (2014) 288–292
290
p 0.0289
p < 0.0001
50
***
CAII [ng/ml]
IgG [g/l]
40 30 20 10 0
PA
AIP
*
1500 1200 900 600
***
*
400 350 300 250 200 150 100 50 0 PA
CP
AIP
CP
Fig. 1. Comparison of serum IgG levels in patients with autoimmune pancreatitis (AIP), pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP).
Fig. 3. Comparison of serum CAII levels in patients with autoimmune pancreatitis (AIP), pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP).
and CP patients (p < 0.001; Figs. 1–3). In AIP patients the median IgG levels were 19.7 g/l (range 11.3–34.7 g/l), IgG4 levels were 301.9 mg/dl (188.4–879.5 mg/l) and anti-CAIIAb 81.82 ng/ml (12.9–1254.8 ng/ml). In PA patients the median IgG levels were 10.61 g/l (range 5.92–28.8 g/l), IgG4 123.2 mg/dl (58.7–378.1 mg/ l) and anti-CAIIAb 28.6 ng/ml (3.27–276.2 ng/ml). There was no statistically significant difference between IgG, IgG4 and antiCAIIAb serum level in PA and CP patients (Figs. 1–3). ROC curves for the abilities of IgG, IgG4 and CAII to distinguish between AIP, PA and CP are plotted in Fig. 4. IgG4 for the cut-off 210 mg/dl showed the best sensitivity and specificity (83.8% and 89.5%) in AIP diagnosis compared to IgG (69.3% and 87.3% respectively; cut-off 15 g/l) and anti-CAIIAb (45.3% and 74.3%; cut-off 38.4 ng/ml). Area under the curve (AUC) was 0.940 (95%CI 0.926–0.968) for IgG4, 0.818 (95%CI 0.8–0.897) for IgG and 0.632 (95%CI 0.596–0.719) for CAII (Fig. 4). However 16 (35.5%) patients with PA and 14 (25.4%) patients with CP had IgG4 levels greater than 140 mg/dl. Moreover in 3 (6.67%) patients with PA those values were greater than 280 mg/dl; therefore, elevation of serum IgG4 levels alone cannot rule out pancreatic cancer. No patients with CP had IgG4 more than 280 mg/dl.
diagnosis to avoid performance of unnecessary surgery for presumed pancreatic cancer. However, the first diagnostic goal is to exclude pancreatic cancer, so in the focal form, pancreatic biopsy is recommended. If pancreatic biopsy is not diagnostic, a careful evaluation of AIP criteria is necessary to decide on management. The decision about pharmacotherapy with steroids or surgical treatment is a clinical challenge and should be made only in experienced centers [11]. In the study of van Heerde et al. for a total of 274 pancreatoduodenectomy performed for presumed malignancy, the prevalence of benign disease was 8.4%, including 2.6% of AIP. If diagnostic criteria would have been verified, surgery could have been avoided probably in one to five AIP patients [12]. However the correct diagnosis is extremely difficult in IgG4negative type 1 of AIP, with normal serum IgG4 levels. Paik et al. have recently reported that among patients with type 1 of AIP, 75% IgG4negative subjects were operated, for suspicion of malignancy, compared to 26% of IgG4-positive patients [13]. The elevated serum IgG4 levels represent the serology criterion for AIP diagnosis. We reported that high IgG4 had a sensitivity of 83.8% and a specificity of 89.5%, indicating that IgG4 is useful both for the AIP diagnosis and for differentiating it from pancreatic 1,0
IgG4
4. Discussion For the patients presenting with obstructive jaundice and a pancreatic mass, AIP should be considered as a differential
Sensitivity
p < 0.0001
1000
***
***
CAII
IgG
0,6
0,4
800
IgG4 [mg/dl]
0,8
600 0,2
400 200
0,0 0,0
0
0,2
0,4
0,6
0,8
1,0
1 - Specificity
PA
AIP
CP
Fig. 2. Comparison of serum IgG4 levels in patients with autoimmune pancreatitis (AIP), pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP).
Fig. 4. ROC curves analyses of IgG4, IgG and CAII for the diagnosis of autoimmune pancreatitis. Area under the curve (AUC) was 0.940 for IgG4, 0.818 for IgG and 0.632 for CAII (Fig. 4).
R. Talar-Wojnarowska et al. / Advances in Medical Sciences 59 (2014) 288–292
cancer. Other reports have also shown the usefulness of IgG4 in AIP diagnosis [8,14,15]. A meta-analysis of seven studies showed the variation in sensitivity and specificity, ranging from 67 to 94% and 89 to 100%, respectively [8]. In our study the additional measurement of IgG and anti-CAIIAb did not further increased the sensitivity and negative predictive value of IgG4. According to the published data the sensitivity, specificity, and positive predictive values for elevated serum IgG4 (>140 mg/dl) for diagnosis of AIP were 76%, 93%, and 36%, respectively, and 53%, 99%, and 75% for IgG4 of >280 mg/dl [15]. In recently published study IgG4 sensitivity was 68% [13]. Differences in IgG4 sensitivity and specificity may be partly due to the use of different assays to measure serum IgG4 and different cut-offs for the upper limit of normal value, as well as variations in diagnostic criteria used in individual countries, which may be associated with histological differences between type-1 and type-2 of AIP. Several studies reported the presence of elevated IgG4 serum levels also in patients with pancreatic cancer and chronic pancreatitis, including alcoholic CP [15,16]. In the study of Aparisi et al., 8.1% of patients with alcoholic CP had elevated IgG4 levels [7], in our study it was even more – 25.4%. Other authors observed, that among patients with elevated IgG4, non-AIP subjects were more likely to be female (45% vs 9%) [15]. In our work – similarly like in the work of Park et al. – the latter was not observed [13]. It was observed that serum IgG4 levels were elevated in 13/135 (10%) of pancreatic cancer patients; however, only 1% had IgG4 levels >280 mg/dl, compared with 53% in AIP patients [15]. Kamisawa et al. reported a case of patient with pancreatic adenocarcinoma with significantly elevated IgG4 level–433 mg/ dl. Elevated serum IgG4 levels continued after the resection. On histology, there were no AIP findings, however there were signs of lymphodenopathy related to an IgG4-related systemic disease [16]. In our study all patients with PA had the diagnosis confirmed histologically. None of the patients with PA and high IgG4 level had histological evidence of AIP, either type 1 or type 2. These findings suggest that, in our series, the IgG4 elevation in PA patients do not indicate undiagnosed concomitant AIP. Moreover, in this group of patients – except for one of them – we did not identify any of associated diseases which may be responsible for high IgG4 levels. In one patient the features of IgG4-related disease were present including sclerosing cholangitis and retroperitoneal fibrosis. The reason for IgG4 elevation in other PA patients remains unclear and needs further examinations. In normal subjects, IgG4 constitutes only 3–7% of total serum IgG. Total serum IgG level may be also elevated in AIP patients, however IgG4 level is more specific. In the study of Aparisi et al. the percentage of patients with elevated IgG levels was significantly higher in subjects with alcoholic CP (36%) and idiopatic CP (42.6%) than in control group (20%) [7]. In our study, as expected, the sensitivity and specificity of IgG in AIP diagnosis were lower compared to IgG4 assessment. Increased level of anti-CAIIAb, next analyzed marker, was observed in the sera of patients with several autoimmune diseases, including AIP [17]. In the study of Okazaki et al., the anti-CAIIAb was present in 58.8–88.9% patient with AIP and 64–67.6% with Sjo¨gren syndrome [7,9,18]. Moreover, the anti-CAIIAb was also detected in 10.5–45.8% patients with alcoholic CP [7,9]. Earlier other authors detected the anti-CAIIAb in 11 of 33 patients with idiopatic CP compared to only 1 of 21 in healthy controls [19]. The results suggest that CAII is one candidate target antigen recognized during the autoimmune pathophysiology, however its role in cancer is not clear. In the study of Hosoda et al., the anti-CAIIAb were not detected in patients with PA. Therefore, the authors concluded that the antiCAII antibody may be useful tool for the differential diagnosis of
291
AIP and pancreatic cancer [9]. However, in our study anti-CAIIAb had the lowest sensitivity and specificity compared to other analyzed markers, increasing not only in CP patients but also in patients with pancreatic cancer. Sheng et al. have recently reported altered expression of CAII associated with pancreatic carcinogenesis. They observed that overexpression of CAII in patients with PA was correlated with tumor differentiation and better prognosis, being an independent prognostic indicator [20]. 5. Conclusions We conclude that IgG4 at cut-off 210 mg/dl showed the best sensitivity and specificity in AIP diagnosis compared to IgG and anti-CAIIAb, however elevations of serum IgG4 may be seen in subjects without AIP, including pancreatic cancer. High levels of anti-CAIIAb are frequently seen in subjects with PA and cannot be used to distinguish AIP from pancreatic cancer. Conflict of interests The authors have no conflicts of interest to declare. Financial disclosure None declared. References [1] Brauner E, Lachter J, Ben-Ishay O, Vlodavsky E, Kluger Y. Autoimmune pancreatitis misdiagnosed as a tumor of the head of the pancreas. World J Gastrointest Surg 2012;4:185–9. [2] Buechter M, Klein CG, Kloeters C, Gerken G, Canbay A, Kahraman A. Diagnostic dilemma in a patient with jaundice: how to differentiate between autoimmune pancreatitis, primary sclerosing cholangitis and pancreas carcinoma. Case Rep Gastroenterol 2012;6:211–6. [3] Ketwaroo GA, Sheth S. Autoimmune pancreatitis. Gastroenterol Rep 2013;1: 27–32. [4] Takuma K, Kamisawa T, Gopalakrishna R, Hara S, Tabata T, Inaba Y, et al. Strategy to differentiate autoimmune pancreatitis from pancreas cancer. World J Gastroenterol 2012;18:1015–20. [5] Kamisawa T, Tabata T, Hara S, Kuruma S, Chiba K, Kanno A, et al. Recent advances in autoimmune pancreatitis. Front Physiol 2012;3:374. [6] Shimosegawa T, Chari ST, Frulloni L, Kamisawa T, Kawa S, Mino-Kenudson M, et al. International consensus diagnostic criteria for autoimmune pancreatitis: guidelines of the International Association of Pancreatology. Pancreas 2011;40:352–8. [7] Aparisi L, Farre A, Gomez-Cambronero L, Martinez J, De Las Heras J, Corts J, et al. Antibodies to carbonic anhydrase and IgG4 levels in idiopathic chronic pancreatitis: relevance for diagnosis of autoimmune pancreatitis. Gut 2005;54:703–9. [8] Morselli-Labate AM, Pezzilli RJ. Usefulness of serum IgG4 in the diagnosis and follow up of autoimmune pancreatitis: a systematic literature review and meta-analysis. Gastroenterol Hepatol 2009;24:15–36. [9] Hosoda H, Kawa-Takatsuji M, Shnmura W, Hashimoto N, Ozaki Y, Ikeda Y. Potential differential diagnosis of autoimmune pancreatitis and pancreatic cancer using carbonic anhydrase II antibody. Pancreas 2008;37:e1–7. [10] Kivela¨ AJ, Kivela¨ J, Saarnio J, Parkkila S. Carbonic anhydrases in normal gastrointestinal tract and gastrointestinal tumours. World J Gastroenterol 2005;11:155–63. [11] Frulloni L, Amodio A, Katsotourchi AM, Vantini I. A practical approach to the diagnosis of autoimmune pancreatitis. World J Gastroenterol 2011;17: 2076–9. [12] van Heerde MJ, Biermann K, Zondervan PE, Kazemier G, van Eijck CHJ, Pek C, et al. Prevalence of autoimmune pancreatitis and other benign disorders in pancreatoduodenectomy for presumed malignancy of the pancreatic head. Dig Dis Sci 2012;57:2458–65. [13] Paik WH, Ryu JK, Park MJ, Song BJ, Park JK, Kim YT, et al. Clinical and pathological differences between serum immunoglobulin G4-positive and negative type 1 autoimmune pancreatitis. World J Gastroenterol 2013;19: 4031–8. [14] Kawa S, Ito T, Watanabe T, Maruyama M, Hamano H, Maruyama M, et al. The utility of serum IgG4 concentrations as a biomarker. Int J Rheumatol 2012;2012:198314. [15] Ghazale A, Chari ST, Smyrk TC, Levy MJ, Topazian MD, Takahashi N, et al. Value of serum IgG4 in the diagnosis of autoimmune pancreatitis and in distinguishing it from pancreatic cancer. Am J Gastroenterol 2007;102:1646–53. [16] Kamisawa T, Chen PY, Tu Y, Nakajima H, Egawa N, Tsuruta K, et al. Pancreatic cancer with a high serum IgG4 concentration. World J Gastroenterol 2006; 12(38):6225–8.
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[17] Smyk DS, Rigopoulou EI, Koutsoumpas AL, Kriese S, Burroughs AK, Bogdanos DP. Autoantibodies in autoimmune pancreatitis. Int J Rheumatol 2012; 1–8. [18] Okazaki K, Uchida K, Ohana M, Nakase H, Uose S, Inai M, et al. Autoimmunerelated pancreatitis is associated with autoantibodies and a Th1/Th2-type cellular immune response. Gastroenterology 2000;118:573–81.
[19] Kino-Ohsaki J, Nishimori I, Morita M, Okazaki K, Yamamoto Y, Onishi S, et al. Serum antibodies to carbonic anhydrase I and II in patients with idiopathic chronic pancreatitis and Sjo¨gren’s syndrome. Gastroenterology 1996;110:1579–86. [20] Sheng W, Dong M, Zhou J, Li X, Dong Q. Down regulation of CAII is associated with tumors differentiation and poor prognosis in patients with pancreatic cancer. J Surg Oncol 2013;107:536–43.
Contents lists available at ScienceDirect
Advances in Medical Sciences journal homepage: www.elsevier.com/locate/advms
Original Research Article
Utility of serum IgG, IgG4 and carbonic anhydrase II antibodies in distinguishing autoimmune pancreatitis from pancreatic cancer and chronic pancreatitis Renata Talar-Wojnarowska a,*, Anita Ga˛siorowska a, Marek Olakowski b, Daria Dranka-Bojarowska b, Paweł Lampe b, Jacek S´migielski d, Magdalena Kujawiak c, Janina Grzegorczyk c, Ewa Małecka-Panas a a
Department of Digestive Tract Diseases, Medical University of Lodz, Poland Department of Digestive Tract Surgery, Silesian Medical University, Katowice, Poland c Department of Microbiology and Laboratory Medical Immunology, Faculty of Medicine, Medical University of Lodz, Poland d Department of Thoracic Surgery, General and Oncological Surgery, Medical University of Lodz, Poland b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 18 May 2014 Accepted 12 August 2014 Available online 26 August 2014
Purpose: Autoimmune pancreatitis (AIP) can mimic pancreatic cancer in its clinical presentation, imaging features and laboratory parameters. The aim of our study was to compare IgG, IgG4 and antiCAIIAb serum levels in patients with AIP, pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP) and to assess their clinical significance and utility in differential diagnosis of pancreatic diseases. Patient/methods: The study included 124 patients: 45 with PA, 24 with AIP and 55 with CP. Peripheral venous blood samples were obtained from all analyzed patients at the time of hospital admission and total IgG, IgG4 and anti-CAIIAB serum levels were measured using ELISA tests. Results: Serum levels of IgG, IgG4 and anti-CAIIAb were significantly higher in patients with AIP compared to PA and CP patients (p < 0.001). In AIP patients the median IgG levels were 19.7 g/l, IgG4 levels – 301.9 mg/dl and anti-CAIIAb – 81.82 ng/ml, compared to 10.61 g/l, 123.2 mg/dl and 28.6 ng/ml, respectively, in PA patients. IgG4 for the cut-off 210 mg/dl showed the best sensitivity and specificity (83.8% and 89.5%) in AIP diagnosis compared to IgG (69.3% and 87.3%, respectively) and anti-CAIIAb (45.3% and 74.3%). However, 16 (35.5%) patients with PA and 14 (25.4%) patients with CP had IgG4 levels greater than 140 mg/dl. Moreover, in 3 (6.67%) patients with pancreatic cancer those values were greater than 280 mg/dl. No patients with CP had IgG4 more than 280 mg/dl. Conclusions: IgG4 at cut-off 210 mg/dl showed the best sensitivity and specificity in AIP diagnosis compared to IgG and anti-CAIIAb, however elevations of serum IgG4 may be seen in subjects without AIP, including pancreatic cancer. ß 2014 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
Keywords: Autoimmune pancreatitis Pancreatic adenocarcinoma Chronic pancreatitis IgG4 IgG Carbonic anhydrase II (CAII)
1. Introduction Autoimmune pancreatitis (AIP) is a distinct form of pancreatitis characterized clinically by frequent presentation with obstructive jaundice with or without a pancreatic mass. AIP can mimic pancreatic cancer in its clinical presentation, imaging features and laboratory parameters [1,2]. The diagnosis of AIP remains a
* Corresponding author at: Department of Digestive Tract Diseases, Medical University of Lodz, Kopcinskiego 22, 90-153 Lodz, Poland. Tel.: +48 42 678 64 80; fax: +48 42 678 64 80. E-mail address: [email protected] (R. Talar-Wojnarowska).
challenging test for clinicians. Due to clinical and radiological similarities but a completely different prognosis and therapy, it is of fundamental importance to differentiate between pancreatic cancer and autoimmune pancreatitis. The method of choice for AIP treatment is steroid therapy being clinically, morphologically, and serologically effective in AIP patients. However, steroid treatment should be started after negative evaluation for pancreatic cancer [3,4]. It is known that there are two clinicopathologically different types of autoimmune pancreatitis: more frequent type-1 AIP, called lymphoplasmacytic sclerosing pancreatitis (LPSP) and type 2 characterized by neutrophilic infiltration in the epithelium of the pancreatic duct. In general, the most common clinical features of
http://dx.doi.org/10.1016/j.advms.2014.08.003 1896-1126/ß 2014 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
R. Talar-Wojnarowska et al. / Advances in Medical Sciences 59 (2014) 288–292
type-1 of AIP are weight loss and painless jaundice, the last being reported to occur in up to 100% of patients. Type-2 AIP patients are younger, more likely have acute pancreatitis or ulcerative colitis, and rarely show elevation of serum IgG4 compared with type-1 AIP patients [5]. As it is sometimes difficult to obtain adequate biopsy material from the pancreas, AIP is currently diagnosed based on careful consideration of a combination of characteristic clinical, serological, morphological, and histopathological features [4,6]. High serum IgG4 concentrations have been observed in 90% of patients with AIP, less frequent in patients with pancreatic cancer, chronic pancreatitis, primary biliary cirrhosis and primary sclerosing cholangitis. Serum IgG4 concentration is therefore considered a reliable marker for the diagnosis of AIP and has been included in various diagnostic criteria. Moreover, increased levels of serum antibodies, including antibodies against carbonic anhydrase II (CAII), have been reported in AIP [7,8]. Carbonic anhydrase is a zinc metalloenzyme of cytoplasmatic location. There are at least twelve CA isoenzymes with CAII expressed in the ductal epithelial cells of several exocrine glands, including pancreas, salivary gland, kidney and liver (bile ducts). Anti-CAII antibodies (anti-CAIIAb) were described as a serological marker not only for AIP, but also for autoimmune hepatitis, Sjo¨gren syndrome, systemic lupus erythematosus, polymyositis and dermatomyositis [9,10]. The aim of our study was to compare IgG, IgG4 and anti-CAIIAb serum levels in patients with AIP type-1, pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP) and to assess their clinical significance and utility in differential diagnosis of pancreatic diseases.
2. Patients and methods
289
pancreatic duct and its branches shown by ultrasound, computed tomography or endoscopic retrograde pancreatography or histologically proven CP. Alcoholic CP was diagnosed in patients who consumed more than 80 g/day of alcohol (males) and at least 40 g/ day of alcohol (females) for 5 or more years, before the first symptoms of the disease. The associations of the IgG, IgG4, and anti-CAIIAb and clinical data at diagnosis have been evaluated. The following clinical variables were analyzed: age and sex of patients, presence of jaundice, diabetes mellitus, weight loss >10% and prior episodes of acute pancreatitis. In patients with PA additionally tumor size, histological grade, lymph node involvement and distant metastases were analyzed. 2.2. Methods Peripheral venous blood samples were obtained from all analyzed patients at the time of hospital admission. Total IgG serum level was measured using specific enzyme-linked immunosorbent assay (ELISA) (Immunodiagnostik AG, Bensheim, Germany) in accordance with the test procedure. Results were expressed in g/l. The detection limit was 1.9 ng/ml. There was no cross reactivity with other serum proteins. The serum concentrations of IgG4 and anti-CAIIAb were measured with ELISA according to the producer recommendations (Uscn Life Science Inc., Wuhan, China). Results were expressed in mg/dl for IgG4 and in ng/ml for anti-CAIIAb. The sensitivity of the immunoassays was as follows: 45.7 ng/ml for IgG4 and 0.093 ng/ ml for anti-CAIIAb. There were no significant cross-reactions or interferences between human IgG4 or anti-CAIIAb and analogs. Normal values for analyzed parameters were previously assessed as 8–16 g/l for IgG, 8–140 ng/ml for IgG4 and 0–31 ng/ml for antiCAIIAb.
2.1. Patients 2.3. Statistical analysis The study included 124 patients: 45 with PA (27 men and 18 women aged 49–83), 24 with AIP type-1 (11 men and 13 women aged 42–71) and 55 with CP (36 men and 19 women, aged 27–73). The written informed consent was obtained from all the patients. The study protocol was approved by the ethical committee of Lodz Medical University. In all patients with pancreatic adenocarcinoma the diagnosis was confirmed with pathology of surgical specimen (39 patients) or pancreatic tissue biopsy (6 patients). The diagnosis of AIP type-1 was established according to the International Consensus Diagnostic Criteria (ICDC) based to the pancreatic histology and/or imaging, serology, other organ involvement and response to steroid treatment (6). Patients with AIP had no obvious cause of CP, such as alcoholism, gallstones, hypercalcaemia or other identifiable etiologic factors. The diagnosis of CP was determined by histology and/or standard imaging criteria and clinical course. The diagnosis of CP was based on the following findings: calcifications, pancreatic stones, dilatation, stenosis, or cyst formation of the main
Statistical analysis comprised arithmetical mean and standard deviation. To determine differences between groups Kruskal– Wallis test and Fisher’s exact test were used. p-Values <0.05 were considered to be significant. Receiver operating characteristic (ROC) curves depicting the ability to discriminate between AIP, PA and CP were plotted for each of the markers.
3. Results In our study there was no statistically significant differences in clinical features between patients with PA and AIP, what is shown in Table 1. Patients with CP were significantly younger and were less likely to have jaundice (Table 1). Only 20.8% patients with AIP as well as 26.6% with CP and 15.5% with PA had a prior episode of acute pancreatitis (p > 0.05). Serum levels of IgG, IgG4 and anti-CAIIAb were significantly higher in patients with autoimmune pancreatitis compared to PA
Table 1 Comparison of clinical features in patients with autoimmune pancreatitis (AIP), pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP). Clinical features
PA (n = 45)
AIP (n = 24)
CP (n = 55)
p
Age Sex (F/M) Diabetes mellitus Jaundice Weight loss >10% Acute pancreatitis
71 3.9 23/22 33% (15/45) 55.5% (25/45) 42.2% (19/45) 15.5% (7/45)
64 4.5 15/9 41.6% (10/24) 45.8% (11/24) 29.2% (7/24) 20.8% (5/24)
49 5.7 35/20 30.9% (17/55) 18.2% (10/55) 32.7% (18/55) 26.6% (12/45)
0.01* NS NS 0.01* NS NS
*
CP vs PA and AIP.
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290
p 0.0289
p < 0.0001
50
***
CAII [ng/ml]
IgG [g/l]
40 30 20 10 0
PA
AIP
*
1500 1200 900 600
***
*
400 350 300 250 200 150 100 50 0 PA
CP
AIP
CP
Fig. 1. Comparison of serum IgG levels in patients with autoimmune pancreatitis (AIP), pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP).
Fig. 3. Comparison of serum CAII levels in patients with autoimmune pancreatitis (AIP), pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP).
and CP patients (p < 0.001; Figs. 1–3). In AIP patients the median IgG levels were 19.7 g/l (range 11.3–34.7 g/l), IgG4 levels were 301.9 mg/dl (188.4–879.5 mg/l) and anti-CAIIAb 81.82 ng/ml (12.9–1254.8 ng/ml). In PA patients the median IgG levels were 10.61 g/l (range 5.92–28.8 g/l), IgG4 123.2 mg/dl (58.7–378.1 mg/ l) and anti-CAIIAb 28.6 ng/ml (3.27–276.2 ng/ml). There was no statistically significant difference between IgG, IgG4 and antiCAIIAb serum level in PA and CP patients (Figs. 1–3). ROC curves for the abilities of IgG, IgG4 and CAII to distinguish between AIP, PA and CP are plotted in Fig. 4. IgG4 for the cut-off 210 mg/dl showed the best sensitivity and specificity (83.8% and 89.5%) in AIP diagnosis compared to IgG (69.3% and 87.3% respectively; cut-off 15 g/l) and anti-CAIIAb (45.3% and 74.3%; cut-off 38.4 ng/ml). Area under the curve (AUC) was 0.940 (95%CI 0.926–0.968) for IgG4, 0.818 (95%CI 0.8–0.897) for IgG and 0.632 (95%CI 0.596–0.719) for CAII (Fig. 4). However 16 (35.5%) patients with PA and 14 (25.4%) patients with CP had IgG4 levels greater than 140 mg/dl. Moreover in 3 (6.67%) patients with PA those values were greater than 280 mg/dl; therefore, elevation of serum IgG4 levels alone cannot rule out pancreatic cancer. No patients with CP had IgG4 more than 280 mg/dl.
diagnosis to avoid performance of unnecessary surgery for presumed pancreatic cancer. However, the first diagnostic goal is to exclude pancreatic cancer, so in the focal form, pancreatic biopsy is recommended. If pancreatic biopsy is not diagnostic, a careful evaluation of AIP criteria is necessary to decide on management. The decision about pharmacotherapy with steroids or surgical treatment is a clinical challenge and should be made only in experienced centers [11]. In the study of van Heerde et al. for a total of 274 pancreatoduodenectomy performed for presumed malignancy, the prevalence of benign disease was 8.4%, including 2.6% of AIP. If diagnostic criteria would have been verified, surgery could have been avoided probably in one to five AIP patients [12]. However the correct diagnosis is extremely difficult in IgG4negative type 1 of AIP, with normal serum IgG4 levels. Paik et al. have recently reported that among patients with type 1 of AIP, 75% IgG4negative subjects were operated, for suspicion of malignancy, compared to 26% of IgG4-positive patients [13]. The elevated serum IgG4 levels represent the serology criterion for AIP diagnosis. We reported that high IgG4 had a sensitivity of 83.8% and a specificity of 89.5%, indicating that IgG4 is useful both for the AIP diagnosis and for differentiating it from pancreatic 1,0
IgG4
4. Discussion For the patients presenting with obstructive jaundice and a pancreatic mass, AIP should be considered as a differential
Sensitivity
p < 0.0001
1000
***
***
CAII
IgG
0,6
0,4
800
IgG4 [mg/dl]
0,8
600 0,2
400 200
0,0 0,0
0
0,2
0,4
0,6
0,8
1,0
1 - Specificity
PA
AIP
CP
Fig. 2. Comparison of serum IgG4 levels in patients with autoimmune pancreatitis (AIP), pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP).
Fig. 4. ROC curves analyses of IgG4, IgG and CAII for the diagnosis of autoimmune pancreatitis. Area under the curve (AUC) was 0.940 for IgG4, 0.818 for IgG and 0.632 for CAII (Fig. 4).
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cancer. Other reports have also shown the usefulness of IgG4 in AIP diagnosis [8,14,15]. A meta-analysis of seven studies showed the variation in sensitivity and specificity, ranging from 67 to 94% and 89 to 100%, respectively [8]. In our study the additional measurement of IgG and anti-CAIIAb did not further increased the sensitivity and negative predictive value of IgG4. According to the published data the sensitivity, specificity, and positive predictive values for elevated serum IgG4 (>140 mg/dl) for diagnosis of AIP were 76%, 93%, and 36%, respectively, and 53%, 99%, and 75% for IgG4 of >280 mg/dl [15]. In recently published study IgG4 sensitivity was 68% [13]. Differences in IgG4 sensitivity and specificity may be partly due to the use of different assays to measure serum IgG4 and different cut-offs for the upper limit of normal value, as well as variations in diagnostic criteria used in individual countries, which may be associated with histological differences between type-1 and type-2 of AIP. Several studies reported the presence of elevated IgG4 serum levels also in patients with pancreatic cancer and chronic pancreatitis, including alcoholic CP [15,16]. In the study of Aparisi et al., 8.1% of patients with alcoholic CP had elevated IgG4 levels [7], in our study it was even more – 25.4%. Other authors observed, that among patients with elevated IgG4, non-AIP subjects were more likely to be female (45% vs 9%) [15]. In our work – similarly like in the work of Park et al. – the latter was not observed [13]. It was observed that serum IgG4 levels were elevated in 13/135 (10%) of pancreatic cancer patients; however, only 1% had IgG4 levels >280 mg/dl, compared with 53% in AIP patients [15]. Kamisawa et al. reported a case of patient with pancreatic adenocarcinoma with significantly elevated IgG4 level–433 mg/ dl. Elevated serum IgG4 levels continued after the resection. On histology, there were no AIP findings, however there were signs of lymphodenopathy related to an IgG4-related systemic disease [16]. In our study all patients with PA had the diagnosis confirmed histologically. None of the patients with PA and high IgG4 level had histological evidence of AIP, either type 1 or type 2. These findings suggest that, in our series, the IgG4 elevation in PA patients do not indicate undiagnosed concomitant AIP. Moreover, in this group of patients – except for one of them – we did not identify any of associated diseases which may be responsible for high IgG4 levels. In one patient the features of IgG4-related disease were present including sclerosing cholangitis and retroperitoneal fibrosis. The reason for IgG4 elevation in other PA patients remains unclear and needs further examinations. In normal subjects, IgG4 constitutes only 3–7% of total serum IgG. Total serum IgG level may be also elevated in AIP patients, however IgG4 level is more specific. In the study of Aparisi et al. the percentage of patients with elevated IgG levels was significantly higher in subjects with alcoholic CP (36%) and idiopatic CP (42.6%) than in control group (20%) [7]. In our study, as expected, the sensitivity and specificity of IgG in AIP diagnosis were lower compared to IgG4 assessment. Increased level of anti-CAIIAb, next analyzed marker, was observed in the sera of patients with several autoimmune diseases, including AIP [17]. In the study of Okazaki et al., the anti-CAIIAb was present in 58.8–88.9% patient with AIP and 64–67.6% with Sjo¨gren syndrome [7,9,18]. Moreover, the anti-CAIIAb was also detected in 10.5–45.8% patients with alcoholic CP [7,9]. Earlier other authors detected the anti-CAIIAb in 11 of 33 patients with idiopatic CP compared to only 1 of 21 in healthy controls [19]. The results suggest that CAII is one candidate target antigen recognized during the autoimmune pathophysiology, however its role in cancer is not clear. In the study of Hosoda et al., the anti-CAIIAb were not detected in patients with PA. Therefore, the authors concluded that the antiCAII antibody may be useful tool for the differential diagnosis of
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AIP and pancreatic cancer [9]. However, in our study anti-CAIIAb had the lowest sensitivity and specificity compared to other analyzed markers, increasing not only in CP patients but also in patients with pancreatic cancer. Sheng et al. have recently reported altered expression of CAII associated with pancreatic carcinogenesis. They observed that overexpression of CAII in patients with PA was correlated with tumor differentiation and better prognosis, being an independent prognostic indicator [20]. 5. Conclusions We conclude that IgG4 at cut-off 210 mg/dl showed the best sensitivity and specificity in AIP diagnosis compared to IgG and anti-CAIIAb, however elevations of serum IgG4 may be seen in subjects without AIP, including pancreatic cancer. High levels of anti-CAIIAb are frequently seen in subjects with PA and cannot be used to distinguish AIP from pancreatic cancer. Conflict of interests The authors have no conflicts of interest to declare. Financial disclosure None declared. References [1] Brauner E, Lachter J, Ben-Ishay O, Vlodavsky E, Kluger Y. Autoimmune pancreatitis misdiagnosed as a tumor of the head of the pancreas. World J Gastrointest Surg 2012;4:185–9. [2] Buechter M, Klein CG, Kloeters C, Gerken G, Canbay A, Kahraman A. Diagnostic dilemma in a patient with jaundice: how to differentiate between autoimmune pancreatitis, primary sclerosing cholangitis and pancreas carcinoma. Case Rep Gastroenterol 2012;6:211–6. [3] Ketwaroo GA, Sheth S. Autoimmune pancreatitis. Gastroenterol Rep 2013;1: 27–32. [4] Takuma K, Kamisawa T, Gopalakrishna R, Hara S, Tabata T, Inaba Y, et al. Strategy to differentiate autoimmune pancreatitis from pancreas cancer. World J Gastroenterol 2012;18:1015–20. [5] Kamisawa T, Tabata T, Hara S, Kuruma S, Chiba K, Kanno A, et al. Recent advances in autoimmune pancreatitis. Front Physiol 2012;3:374. [6] Shimosegawa T, Chari ST, Frulloni L, Kamisawa T, Kawa S, Mino-Kenudson M, et al. International consensus diagnostic criteria for autoimmune pancreatitis: guidelines of the International Association of Pancreatology. Pancreas 2011;40:352–8. [7] Aparisi L, Farre A, Gomez-Cambronero L, Martinez J, De Las Heras J, Corts J, et al. Antibodies to carbonic anhydrase and IgG4 levels in idiopathic chronic pancreatitis: relevance for diagnosis of autoimmune pancreatitis. Gut 2005;54:703–9. [8] Morselli-Labate AM, Pezzilli RJ. Usefulness of serum IgG4 in the diagnosis and follow up of autoimmune pancreatitis: a systematic literature review and meta-analysis. Gastroenterol Hepatol 2009;24:15–36. [9] Hosoda H, Kawa-Takatsuji M, Shnmura W, Hashimoto N, Ozaki Y, Ikeda Y. Potential differential diagnosis of autoimmune pancreatitis and pancreatic cancer using carbonic anhydrase II antibody. Pancreas 2008;37:e1–7. [10] Kivela¨ AJ, Kivela¨ J, Saarnio J, Parkkila S. Carbonic anhydrases in normal gastrointestinal tract and gastrointestinal tumours. World J Gastroenterol 2005;11:155–63. [11] Frulloni L, Amodio A, Katsotourchi AM, Vantini I. A practical approach to the diagnosis of autoimmune pancreatitis. World J Gastroenterol 2011;17: 2076–9. [12] van Heerde MJ, Biermann K, Zondervan PE, Kazemier G, van Eijck CHJ, Pek C, et al. Prevalence of autoimmune pancreatitis and other benign disorders in pancreatoduodenectomy for presumed malignancy of the pancreatic head. Dig Dis Sci 2012;57:2458–65. [13] Paik WH, Ryu JK, Park MJ, Song BJ, Park JK, Kim YT, et al. Clinical and pathological differences between serum immunoglobulin G4-positive and negative type 1 autoimmune pancreatitis. World J Gastroenterol 2013;19: 4031–8. [14] Kawa S, Ito T, Watanabe T, Maruyama M, Hamano H, Maruyama M, et al. The utility of serum IgG4 concentrations as a biomarker. Int J Rheumatol 2012;2012:198314. [15] Ghazale A, Chari ST, Smyrk TC, Levy MJ, Topazian MD, Takahashi N, et al. Value of serum IgG4 in the diagnosis of autoimmune pancreatitis and in distinguishing it from pancreatic cancer. Am J Gastroenterol 2007;102:1646–53. [16] Kamisawa T, Chen PY, Tu Y, Nakajima H, Egawa N, Tsuruta K, et al. Pancreatic cancer with a high serum IgG4 concentration. World J Gastroenterol 2006; 12(38):6225–8.
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[17] Smyk DS, Rigopoulou EI, Koutsoumpas AL, Kriese S, Burroughs AK, Bogdanos DP. Autoantibodies in autoimmune pancreatitis. Int J Rheumatol 2012; 1–8. [18] Okazaki K, Uchida K, Ohana M, Nakase H, Uose S, Inai M, et al. Autoimmunerelated pancreatitis is associated with autoantibodies and a Th1/Th2-type cellular immune response. Gastroenterology 2000;118:573–81.
[19] Kino-Ohsaki J, Nishimori I, Morita M, Okazaki K, Yamamoto Y, Onishi S, et al. Serum antibodies to carbonic anhydrase I and II in patients with idiopathic chronic pancreatitis and Sjo¨gren’s syndrome. Gastroenterology 1996;110:1579–86. [20] Sheng W, Dong M, Zhou J, Li X, Dong Q. Down regulation of CAII is associated with tumors differentiation and poor prognosis in patients with pancreatic cancer. J Surg Oncol 2013;107:536–43.