Classical pathway complement activity in schizophrenia.

There is considerable evidence to suggest a role for complement in the pathogenesis of schizophrenia, but the data related to the classical pathway complement activity in patients with schizophrenia are conflicting. In the present study, the total hemolytic activity of the complement and the activities of individual complement components, C1, C2, C3 and C4, were determined in the blood serum of schizophrenic patients with positive family history of the disease and healthy subjects. In comparison to the healthy subjects, the mean values of the hemolytic activities of the C1, C3 and C4 complement components in the serum of the schizophrenic patients were significantly higher, and the mean value of the hemolytic activity of the C2 complement component was significantly lower. However, no significant difference was found between the mean values of the total hemolytic activity of complement in schizophrenic patients and healthy subjects. The C3 hemolytic activity was 2.17 times higher in medicated patients than in drug-free patients. Within each group examined no significant difference was found between smokers and non-smokers or between males and females. The results of this study suggest that the pathogenesis of schizophrenia is associated with alterations in activities of complement classical pathway components.