The relationship between serum cytokine levels and degree of psychosis in patients with schizophrenia

Accepted Manuscript

The relationship between serum cytokine levels and degree of psychosis in patients with schizophrenia Shani Dahan , Nicola Luigi Bragazzi , Ayala Yogev , Mayan Bar-Gad , Vivian Barak , Howard Amital , Daniela Amital PII: DOI: Reference:

S0165-1781(18)30183-5 10.1016/j.psychres.2018.07.041 PSY 11590

To appear in:

Psychiatry Research

Received date: Revised date: Accepted date:

27 January 2018 6 February 2018 29 July 2018

Please cite this article as: Shani Dahan , Nicola Luigi Bragazzi , Ayala Yogev , Mayan Bar-Gad , Vivian Barak , Howard Amital , Daniela Amital , The relationship between serum cytokine levels and degree of psychosis in patients with schizophrenia, Psychiatry Research (2018), doi: 10.1016/j.psychres.2018.07.041

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Highlights 

This study has shown that elevated levels of IL6, IL8 and IL2R are related with more severe clinical symptoms measured by the total, negative and general scales of the PANSS. Such associations support the role the immune system may have in the pathogenesis of

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schizophrenia.

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

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The relationship between serum cytokine levels and degree of psychosis in patients with schizophrenia

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Shani Dahan, 2Nicola Luigi Bragazzi, 3Ayala Yogev, , 2Mayan Bar-Gad, 4Vivian Barak, *1Howard Amital,

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*2Daniela Amital

Department of Medicine 'B', Sheba Medical Center, Tel-Hashomer, Israel, Sackler Faculty of Medicine, Tel Aviv University, Israel, 2Postgraduate School of Public Health, Department of Health Sciences (DISSAL),

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University of Genoa, Genoa, Italy, 3Beer-Yaacov- Ness Ziona Mental Health Center, 4Immunology Laboratory for Tumor Diagnosis, Hadassah–Hebrew University Medical Center, Jerusalem, Israel

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Key words: psychosis, schizophrenia, cytokines, inflammation, IL-6, IL-10.

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*The last two authors share equal contribution

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Running title: Cytokines activity and the intensity of psychotic symptoms in psychotic states

Address for correspondence: Prof. Howard Amital Head of Department of Medicine 'B' Sheba Medical Center Tel-Hashomer, 52621, Israel Tel.: + 972 3 530 2652 Fax: + 972 3 535 4796 E-mail: [email protected]

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Abstract Several observations indicate that cytokine concentrations might also relate to the severity of the psychosis. In this study we assessed whether inflammatory and anti-inflammatory cytokine concentrations are associated with the degree of the psychotic manifestations. A group of 41 patients with schizophrenia suffering from an acute psychosis leading to hospitalization in a

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psychiatric ward were assessed for the intensity of their psychotic manifestations by the PANSS score. Serum IL-2R, IL-6, IL-8, IL-10 were analyzed by commercial ELISA kits. These patients were compared to controls without schizophrenia.

At the univariate analysis, statistically significant elevated levels of the cytokines IL-6, IL-2R and IL-8 were

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detected in the sera of the patients with schizophrenia compared to controls. At the multivariate analysis, statistically significance held only for IL-2R concentration. Furthermore, positive correlation was found between symptom severity as measured by the PANSS and IL-6 levels as well as IL-2R levels. In Conclusion, our data indicate that elevated serum concentrations of IL-6, IL-8 and IL-2R are associated

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with severe clinical symptoms measured by the total, general, negative and positive scores of the PANSS

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scale.

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1. Introduction Schizophrenia is a severe mental disorder affecting approximately 1% of the population worldwide (McGrath et al., 2008) The World Health Organization ranked it as one of the top ten illnesses contributing to the global burden of disease (2015; McGrath et al., 2008; Murray and Lopez, 1997). Schizophrenia is a complex multifaceted syndrome characterized by the presence of positive symptoms (e.g., reality distortion,

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as well as disorganized thoughts and behavior), negative symptoms (e.g., a diminished expression symptom cluster), cognitive decline and mood alterations (Carpenter, Jr. et al., 1974). The disorder is characterized by a slow continuous deterioration process with serious implications and heavy costs for both patients and their families. Furthermore, the disease poses a significant economic burden on society in terms of treatment,

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rehabilitation and loss of productivity.

There is a vast spectrum of theories regarding the etiology of schizophrenia, including neuro-developmental (Hornig et al., 2002) and neurodegenerative (Lieberman, 1999a) processes, abnormal neurotransmitter regulation (Abi-Dargham and Meyer, 2014a; Munn, 2000) and viral infections (Kneeland and Fatemi,

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2013). The role for immunologic abnormalities in the pathogenesis schizophrenia was first proposed over 40

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years ago (Anders and Kinney, 2015; Horvath and Mirnics, 2014; Khandaker and Dantzer, 2016). With the advancement of technology and a better understanding of the immune system in recent years, psycho-neuro-

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immunological theories for the development of schizophrenia have been a focus of exponential growing

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research (Barak, 2006; Itzhaky et al., 2012; Jones et al., 2005; Yum et al., 2009). In this context, a broad spectrum of immune system dysregulations has constantly been reported as possible underlying

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mechanisms, along with environmental influences such as infections, stress and nutrition, genetic susceptibility and alterations of neurotransmitter pathways. Changes in mood, cognition and behavior may result from pro-inflammatory cytokines activity and circulating autoantibodies influencing the brain (Agmon-Levin et al., 2009). Evidence has shown that stress and anxiety and depressive mood can affect circulating cytokines as well (Ji et al., 2017; Miranda et al., 2017; Yang et al., 2017). In addition, anti-depressant therapy such as duloxetine administration was shown to prevent increased hippocampal pro-inflammatory interleukin-6 (Zhang et al., 2016) .

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In the recent years, there is a growing body of circumferential evidence linking schizophrenia to autoimmunity. For example, schizophrenia patients were demonstrated to have serum autoantibodies directed against brain structures involved in the pathogenesis of the disease, including the hippocampus, the septum pelucidum, the cingulate gyrus, the amygdala and the frontal cortex (Henneberg et al., 1994; Margari et al., 2013; Weidenhofer et al., 2006). An immunological-mediated response against neurotransmitter

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receptors and molecules has also been described in patients with schizophrenia (Jones et al., 2014). CNS inflammation disrupting the blood-brain barrier turning it permeable to autoantibodies has also been observed (Bechter et al., 2010). Classic autoimmune-related autoantibodies were found in the sera of schizophrenia patients, among these are anti-cardiolipin antibodies, antinuclear antibodies, anti-DNA and

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anti-histone antibodies and anti-NMDA receptors(Audemard-Verger et al., 2016; Firer et al., 1994; Ganguli et al., 1992; Sirota et al., 1993; Villemain et al., 1988).

The aim of our study was to examine the existence of an association between exacerbations of emotional state and intensity of psychiatric symptoms in schizophrenia patients and the activity of the immune system,

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as reflected by the concentrations of inflammatory and anti-inflammatory cytokines in peripheral blood

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samples.

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2. Methods

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2.1 The study population

The study included patients recruited at the Mental Health Center "Beer Yaakov- Ness Ziona." Initial

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evaluation included demographic details and past history of the disorder. Patients had to meet the following inclusion criteria: age 18- 65, diagnosed with a schizophrenic disorder according to DSM-IV. All patients were either during their first psychotic event or suffered from an acute episode of a previously diagnosed disease. None of the patients were during a quiescent period. Patients, who agreed to participate in the study and signed an informed consent form, underwent a comprehensive psychiatric evaluation and an evaluation of acute psychotic exacerbation by the Positive and Negative Syndrome Scale (PANSS). Acute psychotic exacerbation was defined by a PANSS score of 20 or higher (measured by PANSS positive subscale score). Practically, all the included patients had scores above 80. All patients underwent scoring of the Clinical

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Global Impression of Severity (CGI-Severity) scale, ranging from 1 (normal, not at all ill) to 7 (among the most extremely ill patients) (Beneke and Rasmus, 1992). The control subjects were volunteers with no psychiatric history, selected by a medical interview. They agreed to participate in the study and signed an informed consent form. These subjects were recruited from

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different populations without a mental illness.

2.2 Laboratory investigations

Blood samples were drawn and tested for the levels of the cytokines: IL-6, IL-8 IL-10 and of IL-2R (ELISA

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kits of R & D systems, sensitivity 1-15 picograms/ml). These two inflammatory cytokines (IL-6, IL-8 ) and two anti-inflammatory cytokines (IL-10 and receptor agonist IL-2R), were chosen on the grounds of availability.

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All the samples were drawn at the same hour (8:00-9:00- AM) during the first two weeks from admission.

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2.3 Statistical analysis

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The ELISA tests were carried out at the immunology laboratory at Hadassah Ein Kerem.

Before commencing any statistical processing and analysis, data were visually inspected for outliers. Given

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the small size of the sample studied, normality of data distribution was checked using the Shapiro-Wilk test. Continuous data were expressed as mean±standard deviation, whereas categorical variables were computed as percentages, where appropriate. Parametric and non-parametric tests (namely, Student’s test for unpaired samples, Wilcoxon test, and chi-squared test were used for comparing cases with healthy controls. Correlations between clinical variables and serum cytokines were performed according to the Pearson’s coefficients. The following rule of thumb was utilized for interpreting the coefficients (in absolute value): very high or excellent with r greater than 0.90; high in the range 0.70-0.90; moderate in the range 0.50-0.70;

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low in the range 0.30-0.50; little if any correlation less than 0.30. For cases only, multivariate regression analyses were carried out for each serum cytokine concentration, correcting for confounding variables, including the number of years of disease, kind of treatment (typical versus atypical antipsychotics or mixed therapy), length of hospitalization and of drug therapy Kruskal-Wallis was utilized for investigating the effect of treatment on serum cytokine concentrations.

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Figures with p-value <0.05 were considered statistically significant. All statistical analyses were performed with the use of the commercial software “Statistical Package for the Social Sciences” (SPSS version 24.0, IBM, Chicago, IL, USA). 2.4 Ethical approval

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The study was approved by the ethics committee of Beer-Yaacov/ Ness Ziona CHS, located in Soroka

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Medical Center, Beer-Sheva, Israel.

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3. Results

The study included 41 patients with schizophrenia, with median age of 33 years (range 20-63 years). The

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control group consisted of 25 subjects, whose median age was 41 years (range 27-53 years). The acuteness

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of the patients’ disease is underlined by the relatively short duration of their therapy, two and a half weeks. At the univariate analysis, cases and controls differed for age (p=0.0321), sex (p=0.0324) and marital status

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(p-value <0.001). Statistically significant elevated levels of the cytokines IL-6 (p-value <0.001), IL-2R (pvalue <0.001) and IL-8 (p-value <0.01) were detected in the sera of the patients with schizophrenia compared to controls. No statistically significant difference was found for IL-10 (Table 1). At the multivariate regression analysis, IL-2R serum level associated with diagnosis (beta standardized coefficient=0.327, p=0.031), whereas IL-8 concentration was associated with age (beta standardized coefficient=0.480, p=0.001) and only in a borderline way with diagnosis (beta standardized coefficient=0.275, p=0.060). No statistically significant associations could be detected for IL-10 and IL-6 serum concentrations. Further details are shown in Table 2.

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An overview of the major clinical parameters investigated in this study in the sample of schizophrenic patients can be found in Table 2. Positive statistically significant correlation was found between symptom severity as measured by the PANSS and IL-6 levels (r=0.482, p=0.0039, with the overall scale; r=0.466, p=0.0055, with the general score; r=0.350, p=0.0425, with the negative scale), as well as IL-2R levels (r=0.365, p=0.0336, with the overall score; r=0.378, p=0.0276, with the general scale). Correlation was also

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found between IL-8 and some clinical parameters (r=0.478, p=0.0043, with CGI; r=0.394, p=0.0212, with length of hospitalization in weeks; r=0.360, p=0.0366, with the number of disease; r=0.541, p=0.0010, with the length of drug therapy). All significant correlations were of low magnitude; except the correlation between IL-8 serum concentration and the length of drug therapy, being of moderate magnitude. The reader

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is referred to Table 3 for further details.

At the multivariate regression analysis, IL-10 concentration resulted statistically associated with type of treatment (beta standardized coefficient=0.691, p=0.011), the negative PANSS scale (beta standardized

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coefficient=0.814, p=0.017) and the general PANSS scale (beta standardized coefficient=-0.682, p=0.006). IL-6 concentration was associated with CGI (beta standardized coefficient=-0.597, p=0.048), whereas IL-2R

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levels correlated with type of therapy (beta standardized coefficient=0.607, p=0.009) and CGI (beta standardized coefficient=-0.656, p=0.032). More in details, treatment with only typical psychotics resulted

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into lower cytokine concentration with respect to a mixed therapy (p=0.0154, Fig. 1). No statistically

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significant predictors could be found for IL-8 serum concentration; further details are shown in Table 4.

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4. Discussion

In this study, we found a statistically significant correlation between the intensity of psychotic symptoms as measured by the PANSS, and the peripheral blood levels of the cytokines IL-6, IL-8 and IL-2R, even though, at the multivariate regression analysis, statistically significance held only for IL-2R concentration. In addition we have shown that intensive anti-psychotic therapy was related with higher serum concentrations of anti-inflammatory molecules (Fig. 1). Our findings demonstrate that an increase in the severity of psychotic symptoms was accompanied by elevated levels of these pro-inflammatory cytokines. Of note, we also found a negative correlation, although not statistically significant, between the blood levels

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of the anti-inflammatory cytokine IL-10 and the intensity of schizophrenia symptoms. Furthermore, IL-2R levels, and to a less extent IL-10, correlated with the type of treatment received, being higher in patients who were receiving both typical and atypical anti-psychotics. These results are in line with aforementioned findings, indicating increased inflammatory response, or lack of regulation and restrain of this response, in schizophrenia patients (Girgis et al., 2017; Sasayama et al.,

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2013; Singh et al., 2009; Stojanovic et al., 2014). The high co-morbidity of schizophrenia with other autoimmune and chronic inflammatory disorders further suggests a common underlying immune abnormality leading to both conditions (Tiosano et al., 2017). It has been found that a history of any autoimmune disease increases the risk for developing schizophrenia by 45%

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(Eaton et al., 2006). A national cohort study found a significant dose-response association between the occurrence of autoimmune disorders, the number of severe infections and the risk of developing schizophrenia (Benros et al., 2011).

The accepted hypothesis of a dysregulated immune response in the pathogenesis of schizophrenia is of a

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disturbed immune-cytokine balance. Several theories regarding the aberrant cytokine levels phenotype have

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been postulated. One theory suggests that IL-1, IL-2, tumor necrosis factor (TNF), interferon (IFN)-α, and IFN-γ secreted by activated macrophages and T-lymphocytes are the key cytokines contributing to

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schizophrenia development (Smith and Maes, 1995). Others have suggested that schizophrenia might be

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associated with an imbalance in Th1/Th2 cytokines, with a shift towards Th2, which predominate in schizophrenia. Experimental data supporting the Th1/Th2 imbalance theory has been inconsistent (Abi-

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Dargham and Meyer, 2014; Avgustin et al., 2005; Brambilla et al., 2014; Lieberman, 1999b). A metaanalysis from 2008 (Potvin et al., 2008) analyzed data from 62 studies involving a total sample size of 2298 patients with schizophrenia and 1858 healthy controls. Their results show increased levels of cytokines and receptor antagonists associated with the Th2 response, including IL-1 receptor antagonist (IL-1RA), soluble IL-2 receptor (sIL-2R) and IL-6, along with a decrease in the levels of IL-2, associated with Th1 response. Yet, contrarily to expected findings in a Th2 dominated immune response, no increments were found in the levels of IL-4 and no decrements in those of IFN- γ. Further studies from recent years have brought forward interesting patterns of cytokine expression in schizophrenia patients. A correlation was demonstrated

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between the blood levels of IL-1β and TNF- α and the of psychopathology score in the positive and negative syndrome scale (PANSS) in 39 schizophrenia patients (Liu et al., 2010). A significantly elevated expression of IFN- γ and TNF- α genes was found in 15 schizophrenia patients as compared to 15 controls, alongside unchanged gene expression of IL-2 and IL-10, indicating a disturbance in the functioning of Th1 (Freudenreich et al., 2010); A systematic, quantitative review of cross-sectional studies found a significant

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increase in blood levels of IL-1RA, sIL-2R, and IL-6 in patients with schizophrenia (Potvin et al., 2008). On the other hand, a study conducted in India among 50 patients with schizophrenia compared to 20 healthy individuals, found low levels of IL-2 and IL-6 (Singh et al., 2009).

The cytokine IL-6 is produced by activated monocytes and Th2 lymphocytes. It signals a downstream

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proinflammatory response, activating acute phase reactants promoting B cells differentiation (Kishimoto, 2010). Elevated levels of IL-6 have been shown to be associated with smaller hippocampal volume and poorer cognition in schizophrenia (Miller et al., 2011). Recently, it has been found that the mechanism of IL-6 activity involves an epigenetic modification of hyper-methylation, and thus reduced activity, of the

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promoter of GAD67, an enzyme participating in GABA production one of the primary inhibitory

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neurotransmitter in the brain(Guidotti et al., 2000). Changes in GABA activity in the brain are known to play a central role in the mechanism underlying the positive and negative symptoms of schizophrenia (Akil

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et al., 1999; Guidotti et al., 2000). And indeed, the serum levels of IL-6 were shown to be associated with

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illness severity, duration and anti-psychotic treatment (Maes et al., 1994). Another study presented the evidence for the presence of inflammatory activity in the CNS in schizophrenia, by reporting elevated IL-6 Furthermore,

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levels in the cerebrospinal fluid (CSF) of schizophrenia patients (Sasayama et al., 2013).

recent longitudinal studies have shown that elevated IL-6 and CRP levels in childhood are associated with increased risk of developing schizophrenia later in life (Metcalf et al., 2017). Following these finding, a recent small open-label study evaluated tocilizumab (a humanized IL-6 receptor monoclonal antibody) as adjunct treatment. Their results show significant improvement in cognitive function in patients with schizophrenia who were treated with tocilizumab, (Miller et al., 2016). However, a consequent double blinded study of tocilizumab in patients with schizophrenia did not reveal any evidence of favorable behavioral outcomes (Girgis et al., 2017).

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The correlation that was found in our study between IL-8 levels and the severity of psychosis also suggests an existence of an immunological mechanism involved in this disorder. IL-8, a 8 kDa protein and a member of a family of soluble molecules called chemokines, was recently purified and cloned (Djeu et al., 1990). Chemokines play a central role in the immune system, including regulation of neutrophils traffic during acute inflammatory responses, leading to their migration into tissues, discharge of lysosomal enzymes from

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inflammatory cells and generation of oxygen free radicals (Sallusto and Baggiolini, 2008). Interleukin-2 receptor (IL-2R) represents an important signaling component expressed on T lymphocytes. It initiates a signal transduction cascade within these cells, leading to their proliferation, thereby increasing the activity of the cellular immune arm. IL2R-gamma gene has been found to be over-expressed in

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schizophrenia patients in comparison to healthy subjects (Ghazaryan et al., 2014). Previous work demonstrates that soluble IL-2R levels are increased in treatment-naive patients with schizophrenia as well as in treatment-free patients, acutely and chronically ill patients and negative symptoms dominant patients (Rapaport et al., 1994; Rapaport et al., 1989; Rapaport et al., 1993). In addition, a recent longitudinal

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treatment study has suggested that serum soluble IL-2R levels may serve as a biomarker for a subset of

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patients with schizophrenia with treatment-resistant psychosis (Bresee and Rapaport, 2009). The positive correlation between the severity of symptoms and the IL-2R of all its subgroups (IL-2R and soluble IL-2R,

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which antagonizes the former) reflects the activation of this cytokine family in patients with schizophrenia .

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Interestingly, in a study of 64 male subjects with schizophrenia, increased cerebrospinal fluid IL-2 levels following haloperidol withdrawal were a significant predictor of acute psychotic relapse (McAllister et al.,

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1995).

Our study has several limitations; although all the analyses were conducted in patents during an acute psychotic event some of the patients experienced a first episode whereas others suffered an acute attack of a chronic disorder. We did not take in account possible confounders such as smoking status, BMI (body mass index) possible menstruation and metabolic status of the patients (29). In addition we do not have the commutative antipsychotic dosages that were given to the subjects included in the study. In conclusion, in this study we have shown that elevated levels of IL6, IL8 and IL2R have been found in patients with schizophrenia. IL-6 and IL-2R were found to correlate to disease activity as measured by

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PANSS score, while IL-6 levels also correlated with the negative signs measured by the PANSS. . Such correlation supports previous findings linking immunological processes with the pathophysiology of schizophrenia and may indicate a relationship between inflammation and more severe psychopathology in a

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subgroup of patients with schizophrenia.

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Table 1. Descriptive statistics of the cases and controls studied. Variables

Cases

Healthy controls

p-value

Age

35.29±11.82

41.33±9.05

0.0321

Sex

0.0324

Male

29 (70.7%)

11 (44.0%)

Female

12 (29.3%)

14 (56.0%) <0.001

29 (70.7%)

3 (12.0%)

Married

8 (19.5%)

22 (88.0%)

Divorced

4 (9.8%)

0 (0.0%)

Numbers of years ill

13.6±10.8

Length of hospitalization

3.1±4.1

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Not married

in weeks 2.6±4.2

Therapy 30 (73%)

antipsychotic, atypical

29 (71%)

mood stabilizer

14 (34%)

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anti-psychotic, typical

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Length of drug therapy

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Marital status

anti-depressant

2 (5%)

34 (83%)

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benzodiazepine Cytokine concentrations

IL-10

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(picogram/ml)

1.64±1.26

1.51±1.97

0.069

3.04±4.25

1.09±0.57

<0.001

IL-2R

1,332.29±1,024.23

563.72±210.62

<0.001

IL-8

8.12±3.57

5.82±1.53

<0.001

IL-6

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CGI

5.61±0.70

PANSS all

116.80±18.83

PANSS general

59.85±10.25

PANSS negative

28.12±8.12

PANSS positive

28.12±6.48

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CGI-Clinical Global Impression, PANSS- Positive and Negative Syndrome Scale

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Clinical parameter

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Table 2. Multivariate regression analyses of the association between cytokine serum concentration (in pg/ml) and psychiatric disorders, as measured in patients with schizophrenia compared to healthy controls.

Variables

Standardized

p-value

t

regression coefficients Beta regression

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coefficient (Intercept) Sex IL-10

Age

Diagnosis

Sex

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Age

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Marital status Diagnosis

Age

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IL-2R

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(Intercept) Sex

-0.068

-0.435

0.666

-0.202

-1.240

0.222

0.108

0.633

0.531

1.093

0.281

1.048

0.300

-0.194

-1.318

0.194

0.126

0.817

0.418

-0.126

-0.797

0.429

0.195

1.248

0.219

1.457

0.152

-0.156

-1.124

0.267

0.166

1.147

0.258

-0.200

-1.346

0.185

0.327

2.225

0.031*

1.660

0.104

0.184

(Intercept)

IL-6

0.043

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Marital status

2.093

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Marital status Diagnosis (Intercept)

IL-8

Sex

-0.100

-0.751

0.457

Age

0.480

3.429

0.001*

-0.212

-1.473

0.148

0.275

1.930

0.060

Marital status Diagnosis *statistically significant with p-value <0.05.

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Table 3. Pearson’s correlations between clinical parameters and serum cytokine concentrations IL-2R

IL-6

IL-8

CGI

Correlation coefficient

-0.071

0.018

0.027

0.478*

p-value

0.7106

0.9177

0.8810

0.0043

PANSS all

Correlation coefficient

-0.046

0.365*

0.482*

0.028

0.8103

0.0336

0.0039

0.8768

-0.260

0.378*

0.466*

0.031

0.1654

0.0276

0.0055

0.8599

p-value

PANSS general

Correlation coefficient

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p-value

PANSS positive

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Length of drug therapy

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0.148

0.245

0.350*

0.020

p-value

0.4340

0.1622

0.0425

0.9118

Correlation coefficient

0.078

0.147

0.211

0.005

p-value

0.6822

0.4054

0.2300

0.9777

Correlation coefficient

-0.055

0.173

0.040

0.394*

p-value

0.7729

0.3267

0.8208

0.0212

Correlation coefficient

-0.249

0.072

0.128

0.360*

p-value

0.1843

0.6866

0.4696

0.0366

Correlation coefficient

-0.208

0.106

-0.030

0.541*

p-value

0.2702

0.5509

0.8646

0.0010

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Length of hospitalization (in weeks)

Correlation coefficient

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PANSS negative

Numbers of years ill

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IL-10

Clinical parameters

CGI-Clinical Global Impression, PANSS- Positive and Negative Syndrome Scale

*statistically significant with p-value <0.05.

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Table 4. Multivariate regression analysis of the association between clinical parameters and serum cytokine concentrations. *statistically significant with p-value <0.05.

Variables

Non standardized regression

Standardized

coefficients

regression

t

p-value

Standard

coefficient

deviation

3.744

2.256

Sex

-0.521

0.461

Age

0.081

Marital status

1.660

0.114

-0.198

-1.130

0.273

0.041

0.783

1.950

0.067

0.252

0.392

0.119

0.641

0.529

-0.051

0.039

-0.430

-1.289

0.214

0.098

-0.294

-0.842

0.411

0.982

0.347

0.691

2.830

0.011*

-0.010

0.088

-0.038

-0.117

0.908

0.006

0.041

0.028

0.137

0.892

PANSS negative

0.128

0.049

0.814

2.634

0.017*

PANSS general

-0.094

0.030

-0.682

-3.138

0.006*

CGI

-0.668

0.595

-0.373

-1.122

0.277

(Intercept)

-1.517

6.799

-0.223

0.825

Sex

-1.902

1.497

-0.207

-1.271

0.217

Age

0.036

0.129

0.100

0.276

0.785

Marital status

0.589

1.206

0.088

0.489

0.630

Numbers of years ill

0.196

0.121

0.488

1.622

0.119

Numbers of years ill Length of hospitalization

-0.082

(in weeks) Type of therapy

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Length of drug therapy

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IL-10

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PANSS positive

IL-6

coefficient

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(Intercept)

Beta regression

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B regression

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coefficients

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Length of hospitalization -0.263

0.269

-0.273

-0.978

0.339

Type of therapy

1.882

1.003

0.395

1.877

0.074

Length of drug therapy

0.201

0.263

0.213

0.764

0.453

PANSS positive

0.147

0.122

0.227

1.200

0.243

PANSS negative

0.200

0.142

0.411

1.416

0.171

PANSS general

0.134

0.096

-3.434

1.641

233.046

1647.887

Sex

-412.888

362.766

Age

45.296

1.402

0.175

-0.597

-2.093

0.048*

0.141

0.889

-0.186

-1.138

0.267

31.352

0.526

1.445

0.163

105.507

292.310

0.066

0.361

0.722

13.339

29.352

0.137

0.454

0.654

65.123

-0.306

-1.089

0.288

696.847

243.077

0.607

2.867

0.009*

84.965

63.778

0.373

1.332

0.196

30.980

29.682

0.199

1.044

0.308

PANSS negative

52.535

34.303

0.448

1.532

0.140

PANSS general

16.314

23.152

0.165

0.705

0.488

-908.513

397.736

-0.656

-2.284

0.032*

0.864

5.588

0.155

0.879

Sex

-0.887

1.230

-0.115

-0.721

0.478

Age

0.191

0.106

0.637

1.800

0.086

Marital status

-0.449

0.991

-0.080

-0.453

0.655

Numbers of years ill

-0.058

0.100

-0.172

-0.585

0.565

Marital status Numbers of years ill Length of hospitalization

M

(Intercept)

AN US

0.327

CGI

-70.938

Type of therapy

PT

Length of drug therapy

ED

IL-2R (in weeks)

AC

CE

PANSS positive

CGI

(Intercept)

IL-8

CR IP T

(in weeks)

ACCEPTED MANUSCRIPT 19

Length of hospitalization -0.150

0.221

-0.185

-0.678

0.505

Type of therapy

0.711

0.824

0.177

0.862

0.398

Length of drug therapy

0.426

0.216

0.537

1.970

0.062

PANSS positive

-0.047

0.101

-0.087

-0.471

0.643

PANSS negative

0.054

0.116

0.132

0.465

0.646

PANSS general

-0.064

0.079

0.807

1.349

CGI

CR IP T

(in weeks)

AC

CE

PT

ED

M

AN US

CGI-Clinical Global Impression, PANSS- Positive and Negative Syndrome Scale

-0.185

-0.810

0.427

0.167

0.599

0.555

ACCEPTED MANUSCRIPT 20

Legend to Fig. 1 - The effect of type of treatment on serum cytokine levels (only significant findings

AC

CE

PT

ED

M

AN US

CR IP T

presented as an illustration).

ACCEPTED MANUSCRIPT 21

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