The role of tumour necrosis factor alpha and soluble tumour necrosis factor alpha receptors in the symptomatology of schizophrenia

Background Immunological mechanisms may be responsible for the development and maintenance of schizophrenia symptoms. Aim The aim of this study is to measure tumour necrosis factor-alpha (TNF-alpha), soluble tumour necrosis factor-alpha receptor I (sTNF-alpha RI), and soluble tumour necrosis factor-alpha receptor II (sTNF-alpha RII) levels in patients with schizophrenia and healthy individuals, and to determine their relationship with the symptoms of schizophrenia. Methods Serum TNF-alpha, sTNF-alpha RI and sTNF-alpha RII levels were measured. The Positive and Negative Syndrome Scale (PANSS) was administered for patients with schizophrenia (n = 35), and the results were compared with healthy controls (n = 30). Hierarchical regression analyses were undertaken to predict the levels of TNF-alpha, sTNF-alpha RI and sTNF-alpha RII. Results No significant difference was observed in TNF-alpha levels, but sTNF-alpha RI and sTNF-alpha RII levels were lower in patients with schizophrenia. Serum sTNF-alpha RI and sTNF-alpha RII levels were found to be negatively correlated with the negative subscale score of the PANSS, and sTNF-alpha RI levels were also negatively correlated with the total score of the PANSS. Smoking, gender, body mass index were not correlated with TNF-alpha and sTNF-alpha receptor levels. Conclusions These results suggest that there may be a change in antiinflammatory response in patients with schizophrenia due to sTNF-alpha RI and sTNF-alpha RII levels. The study also supports low levels of TNF activity in schizophrenia patients with negative symptoms.