Antibodies to thymocytes in sera of patients with schizophrenia.

Sera from healthy people and from patients with schizophrenia were heated at 56 degrees for 30 min and then kept at 4 degrees . These sera were then tested for cytotoxicity and by the indirect immunofluorescence method with thymocytes, bone-marrow cells, and lymph-node cells of adult C(3)H mice. The cytotoxicity index for mouse thymocytes of sera from 60 healthy donors ranged from 0.00 to 0.4, with an average of 0.08. That of sera from 35 patients with schizophrenia ranged from 0.29 to 0.91, with an average of 0.71. The cytotoxicity index for mouse bone-marrow cells of sera from healthy donors ranged from 0.03 to 0.23, whereas that of sera from patients with schizophrenia ranged from 0.00 to 0.14. Sera of patients at dilutions of 1:8-1:32 displayed immunofluorescence of almost 100% of thymocytes and 58-78% of lymphocytes, whereas sera of healthy donors displayed none. We thus conclude that the sera of patients with schizophrenia contain antibodies against thymic antigens localized on thymocytes and thymus-derived lymphocytes.