Increased levels of CD8+ and CD4+ 45RA+ lymphocytes in schizophrenic patients

Peripheral blood (PB) lymphocyte subpopulations, IgG, IgM, IgA and IgE serum immunoglobulins and C3 and C4 complement fractions were evaluated in 29 schizophrenic patients, 31 of their relatives and 20 healthy subjects. The patients fulfilled DSM-III criteria for schizophrenia, and were unmedicated for 3 months prior to the PB sample collection. When compared to healthy controls and their own relatives, the schizophrenic patients showed a lower level of CD4+ cells, while the CD4+ 45RA+ (naive) subset was significantly higher. Conversely, the number of CD4+ 45RA- (memory) lymphocytes was significantly lower in schizophrenic patients in comparison to their relatives and controls, while the CD8+ supressor/cytotoxic T-cell percentage was significantly higher. No significant differences were observed for the IgG, IgM, IgA, IgE and C3 and C4 complement fraction levels among the three groups. The present data confirm the presence of immunological abnormalities in schizophrenic patients and suggest a possible role of environmental factors in the triggering of an autoimmune pathogenic mechanism.