Association of plasma IL-6 and soluble IL-6 receptor levels with the Asp358Ala polymorphism of the IL-6 receptor gene in schizophrenic patients (original) (raw)
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Genetic variants of IL6 and its receptor are not associated with schizophrenia in Taiwan
Neuroscience Letters, 2010
The pathophysiological process of schizophrenia is still unclear. The levels of interleukine-6 (IL-6) and its receptor, soluble IL-6R, have been reported to be elevated in the plasma and cerebrospinal fluid of schizophrenic patients. In this study, we tested the association of genetic variants of IL-6 and IL-6R with schizophrenia. Genotyping of three single nucleotide polymorphisms (SNP) for each IL-6 (IL-6-1, IL-6-2, and IL-6-3) and IL-6R (rs4845617 = IL-6R1, rs4553185 = IL-6R2, and rs4379670 = IL-6R3) gene was performed in 100 patients with schizophrenia and 113 normal controls. The polymorphisms of IL-6R2 were genotyped using Tetra-primer ARMS PCR. IL-6R3 polymorphisms were genotyped using restriction fragment length polymorphism (RFLP) with Apo I enzyme as the restriction enzyme. All other polymorphisms were genotyped using the direct sequencing method. We found a di-nucleotide haplotype block and a tri-nucleotide haplotype block in the genes of IL-6 and IL-6R, respectively. All six SNPs and their haplotypes failed to show a significant association with schizophrenia. The IL-6-2 SNP showed a nominally significant association with the positive symptoms of schizophrenia (p = 0.0472). We conclude that the genetic variants of IL-6 and IL-6R are not associated with schizophrenia. In order to verify this result, further study using a larger sample size and exploring the association between the genotype of IL-6-2 and plasma level of IL-6 is recommended.
Serum interleukin-6 concentration in schizophrenia: Elevation associated with duration of illness
Psychiatry Research, 1994
Using an enzyme immunoassay (ELBA), we measured serum interleukin-6 (IL-6) concentration in 128 schizophrenic patients (24 of whom were never medicated) and in 110 normal control subjects. Mean serum IL-6 concentration was significantly higher in the schizophrenic patients as compared with the control subjects (p = 0.009). Comparisons within the patient group revealed that serum IL-6 was significantly correlated with duration of illness (r = 0.32, p = 0.0004). After covariation for duration of illness, there was no relationship between IL-6 levels and the production of autoantibodies, clinical state, or medication status. Thus, elevated serum IL-6 levels in schizophrenia develop during the course of illness and may be related to treatment or to disease progression.
Schizophrenia Research and Treatment
Alterations in neuroinflammatory processes have been suggested to contribute to the development of Schizophrenia (SZ); one component of the inflammatory system that has been linked to this disorder is interleukin-6 (IL-6). The minor allele of rs2228145, a functional polymorphism in the IL-6 receptor gene, has been associated to elevated IL-6 plasma levels and increased inflammatory activity, making it an interesting candidate to study as a possible factor underlying clinical heterogeneity in SZ. We studied a sample of 100 patients undergoing treatment with clozapine. Their symptoms were quantified by Brief Psychotic Rating Scale; those with the lowest scores (“remitted”) were compared with the highest (“clozapine treatment resistant”). We determined allelic frequencies for rs2228145 and IL-6 plasma levels. Our results do not support a role of IL-6 in response to treatment with clozapine. Further studies accounting for potential confounding factors are necessary.
The inflammatory response system in treatment-resistant schizophrenia: increased serum interleukin-6
Schizophrenia Research, 1998
There is some evidence that the pathophysiology of schizophrenia is related to activation of the inflammatory response system (IRS ), as indicated by increased serum concentrations of interleukin-6 (IL-6), IL-6 receptor (IL-6R), IL-1R antagonist (IL-1RA) and IL-2R and lower serum concentrations of CC16, an endogenous anti-inflammatory protein with immunosuppressive and anti-inflammatory effects. The aims of the present study were to examine serum CC16 in relation to IL-6, IL-6R and gp130, the IL-6 transducing signal protein, in schizophrenia and in treatmentresistant schizophrenia (TRS ). Serum IL-6 and sIL-6R were significantly higher in medicated schizophrenic patients than in normal controls. Serum IL-6 was significantly higher in TRS than in normal volunteers, whereas schizophrenic patients without TRS showed intermediate values. Serum CC16 was significantly lower in schizophrenic patients with a positive family history for psychoses than in normal volunteers and patients without a positive family history. There was a significant inverse relationship between serum CC16 and serum IL-6 or sIL-6R in schizophrenic patients, but not in normal volunteers. The results suggest that the inflammatory response in schizophrenia, as indicated by increased serum IL-6 and sIL-6R, may be causally related to lower serum CC16 and that the latter might be a trait marker for schizophrenia.
European archives of psychiatry and clinical neuroscience, 2014
The influence of the immune system deregulation on the risk of schizophrenia is increasingly recognized. The aim of this study was to assess the influence of serum interleukin-6 (IL-6) level together with the polymorphism in its gene (IL6 -174G/C) and high sensitivity C-reactive protein (hsCRP) levels on clinical manifestation and cognition in schizophrenia patients. We recruited 151 patients with schizophrenia and 194 healthy control subjects. Psychopathology was evaluated using Operational Criteria for Psychotic Illness checklist, Positive and Negative Syndrome Scale (PANSS) and Scales for Assessment of Positive and Negative Symptoms. Cognitive performance in schizophrenia patients was assessed using following tests: Rey Auditory Verbal Learning Test, Trail Making Test, Verbal Fluency Tests, Stroop and subscales from Wechsler Adults Intelligence Scale-R-Pl (Similarities, Digit Symbol Coding, Digit Span Forward and Backward). Serum IL-6 and hsCRP levels were significantly higher in...
interleukin-6 in Schizophrenia-is There a Therapeutic Relevance
Front. Psychiatry, 2017
Renewing interest in immune aspects of schizophrenia and new findings about the brain-fat axis encourage us to discuss the possible role of interleukin-6 (IL-6) in schizophrenia. Previously, it was suggested that a primary alteration of the innate immune system may be relevant in schizophrenia. Functional dichotomy of IL-6 suggests that this chemical messenger may be responsible for regulating the balance between pro- and anti-inflammatory responses, with tissue-specific properties at the periphery and in the central nervous system. Specific phase of this chronic and deteriorating disorder must be considered, which can involve IL-6 in acute or possible chronic inflammation and/or autoimmunity. We give an overview of IL-6 role in the onset and progression of this disorder, also considering cognitive impairment and metabolic changes in patients with schizophrenia. Data suggest that decreased serum level of IL-6 following antipsychotic therapy could be predisposing factor for the development of obesity and obesity-related metabolic disorders in schizophrenia. As we reviewed, the IL-6 plays significant role in disease genesis and progression, so the use of specific inhibitors may not only be beneficial for exacerbation and alleviation of positive symptoms, but may attenuate cognitive impairment in patients with schizophrenia.
Schizophrenia Research, 2002
Cytokines have been one of the recent focal points of immunological research in schizophrenia. The present study was to assess the serum levels of some of interleukins in schizophrenia and their relationships with the psychopathological parameters. Seventy physically healthy Chinese patients, who met DSM-III-R criteria for schizophrenia and who were drug-free for at least 2 weeks, were compared with 30 age-and sex-matched Chinese normal controls. The psychopathology of schizophrenia was assessed by the Positive and Negative Syndrome Scale (PANSS). Serum levels of IL-6 and IL-8 were measured by sandwich enzyme-linked immunosorbent assay (ELISA), and serum IL-2 level was assayed by radioimmunometric assay (RIA). Serum levels of IL-2, IL-6 and IL-8 were significantly elevated in patients with a chronic form of schizophrenia (all p < 0.05). There was a significant inverse relationship between IL-2 level and the PANSS positive subscale P (r = À 0.31, p = 0.006) and a significant positive correlation between IL-8 level and PANSS negative subscale N (r = 0.25, p = 0.036) in schizophrenic patients. In control subjects, a significant and positive relationship between serum IL-2 and IL-6 (r = 0.513, p = 0.004) was noted, whereas, there was a significant and negative relationship between IL-2 and IL-8 in schizophrenic patients (r = À 0.28, p = 0.02). Our data confirms and supports the view that immune disturbance is involved in schizophrenia, which is compatible with the possibility that Chinese schizophrenic patients have an ongoing autoimmune process. This immune disturbance is related to the subgroup of schizophrenic patients with characteristic clinical variables. The dysfunction of interaction or interadjustment between different cytokines may exist in schizophrenic patients. D
Psychiatria Danubina, 2013
The variations in proinflamatory cytokine levels have been associated with schizophrenia (SCH), duration of illness, psychopathology and treatment. The aim of the study was to investigate serum levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in schizophrenic patients during exacerbation and remission, and its association with course of illness and therapy. We measured serum levels of IL-6 and TNF-α in 43 schizophrenic patients in exacerbation and remission and compared them to 29 healthy controls, matched by sex, age, body mass index (BMI) and smoking habits. The severity of psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). There was no difference in levels of IL-6 and TNF-α in exacerbation compared to remission in schizophrenic patients. IL-6 was higher and TNF-α was lower in schizophrenic patients in both exacerbation and remission in comparison with healthy controls. TNF-α in exacerbation was in negative correlation with I...
A differential role for interleukin-6 and tumor necrosis factor-α in schizophrenia?
Schizophrenia Research, 1997
Pro-inflammatory cytokines are dysregulated in schizophrenia. To determine the nature of the so-called inflammatory syndrome in schizophrenia, we investigated the circulating levels of various cytokines (interleukin (IL)-1 beta, IL-6, tumor necrosis factor (TNF)alpha), their natural antagonist (IL1-ra, TNF-RI, TNF-RII) and leukocyte activation markers (the soluble receptor of interleukin-2, soluble CD14 and soluble CD23) in subjects with chronic schizophrenia (n = 18) and in normal controls (n = 21). The levels of IL-1 beta and its antagonist and the levels of leukocyte activation markers were not significantly differents between patients and controls. Circulating levels of TNF alpha were significantly (p < 0.05) higher in patients than in controls and did not result from variations of its antagonist levels. The significant (p < 0.05) increase in patient IL-6 was related specifically to clinical status, i.e. illness duration. These data suggest a specific cytokine-mediated syndrome in schizophrenia. We hypothesize that TNF alpha and IL-6 reflect the genetic background of disease suceptibility.