Alteration of Serum Levels of Cytokines in Schizophrenic Patients before and after Treatment with Risperidone

Abstract

A growing body of evidence suggests the existence of abnormalities in the immune system of schizophrenic patients. The current study examined serum levels of interleukin (IL) -1β, IL-6, IL-2,interferon(IFN) -γ, and tumor necrosis factor(TNF)-α in schizophrenic patients before and after treatment with risperidone and correlated levels of these cytokines with symptomatology.
 The study group consisted of 24 schizophrenic patients as defined by Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) criteria and 24 healthy controls. Serum cytokine levels were examined using enzyme-linked immunosorbent assay (ELISA). Schizophrenic symptomatology was assessed with the Positive and Negative Syndrome Scale (PANSS) questionnaire.
 The serum levels of TNF-α, IL-1β and IL-6 were significantly higher in participants before treatment compared with the healthy controls and after treatment (p<0.001). IFN-γ and IL-2 levels were significantly lower in participants after treatment compared with before treatment and the healthy controls (p<0.001). Except for IL-6 (p<0.05), there was no significant difference in the levels of TNF-α and IL-1β between the patients receiving treatment and the healthy subjects. Moreover, there was no significant difference in levels of IFN-γ and IL-2 between patients before treatment and the healthy subjects.
 There were no significant correlations between the concentration of cytokines studied and the PANSS. Positive intercorrelations between the production of IFN-γ and IL-2 were detected for sums of all groups(r=0.33, p=0.005). Clinical improvement of treated patients was associated with a reduction in the studied cytokines. It seems that changes in the cytokines level may play a significant role in the psychopathology of these patients.

A Meta-Analysis of the Influence of Antipsychotics on Cytokines Levels in First Episode Psychosis

“…Heterogeneity among studies was marked (I 2 = 74%). After exclusion of the two main heterogeneity contributing studies (Azizi et al [ 38 ]; Subbanna et al [ 35 ]) the results provided the same conclusion. At baseline measurements, levels of IL-1β were significantly higher ( p = 0.02) than HC, but after treatment, this elevation became statistically insignificant ( p = 0.13).…”

“…At baseline measurements, the levels of TNF-α were significantly higher ( p = 0.0002) than HC, but after treatment, this elevation became statistically insignificant ( p = 0.09). Individual exclusion of Azizi et al [ 38 ], Juncal-Ruiz et al [ 32 ], Noto et al [ 40 ] studies rendered the results insignificant.…”

Differences in inflammatory marker profiles and cognitive functioning between deficit and nondeficit schizophrenia

“…Therefore, it has been proposed that immunologic abnormalities are likely to be involved in the development of schizophrenia ( 37 ), and several previous studies did find the upregulation of proinflammatory cytokine levels and downregulation of anti-inflammatory cytokine levels in first-episode and drug-naïve schizophrenia patients ( 38 , 39 ), while some other studies failed to replicate the results and even presented the opposite direction ( 40 , 41 ). A recent study found that antipsychotic drugs could modulate inflammation levels and alleviate clinical symptoms in schizophrenia ( 42 ), but also with mixed results between other studies ( 43 ). The discrepancies in studies may be attributed to several factors, including different sample sizes, antipsychotic drugs used, duration of treatment, and different disease statuses.…”

Higher Dietary Inflammation in Patients with Schizophrenia: A Case-Control Study in Korea

“…Increased levels of inflammatory cytokines have also been observed in patients with schizophrenia. Studies regarding humans and animals have identified chronic inflammation as a risk factor for schizophrenia [14][15][16][17].…”