26. The study of natural killer cell activity in patients with at-risk mental state and with the first-episode schizophrenia

Abstract

Several studies have shown a decrease of natural killer cell activity (NKCA) in patients with chronic schizophrenia. However, the role of natural killer cells in the pathogenesis of the disease, as well as the influence of psychotropic therapy on their activity is not well understood. The aim of the current study was to compare the NKCA in male patients with at-risk mental state (n = 19) and with the first-episode schizophrenia (n = 33). The effect of serotonin and psychotropic therapy on NKCA also was observed. Twenty-two healthy sex and age matched donors were examined as a control. The NKCA was expressed as an index of cytotoxicity (IC, %). The greatest decrease of NKCA was noticed in patients with at-risk mental state (IC = 29.6%). Its value was higher (IC = 43.8%) in patients with the first-episode schizophrenia than with at-risk mental state (p < 0.05). Nevertheless NKCA remained below the control (IC = 65.2%, p < 0.001) in both groups of patients. NKCA significantly changed during therapy in patients with the first-episode schizophrenia. These data indicate an involvement of natural killer cells in a response to the antipsychotic treatment. Serotonin added to the cell culture in vitro enhanced NKCA to normal (p < 0.05) only in those patients with the first-episode schizophrenia who responded positively to the treatment. In conclusion, these results suggest that NKCA decreases at a preclinical stage of schizophrenia and changes during psychotropic therapy.