Decreased production of interleukin-2 (IL-2), IL-2 secreting cells and CD4+ cells in medication-free patients with schizophrenia.

ABSTRACT

There are a number of indications that schizophrenia is associated with changes in the immune system. Although functional studies have mostly demonstrated decreased in vitro production of IL-2 by peripheral blood mononuclear cells (PBMCs) stimulated with mitogen, the reason is unclear. The aim of the study was to explore the relationship between IL-2 production and CD4+ cells which mainly secret IL-2 in non-Caucasian patients with schizophrenia. Blood CD4+ cells and mitogen-stimulated IL-2 secreting cells identified by an immunohistochemical study with the alkaline phosphatase/anti-alkaline phosphatase (APAAP) technique, and in vitro IL-2 production with radioimmunometric assay (RIA) were measured in 30 schizophrenic patients and 30 normal control subjects matched for sex, age and race. The results showed that blood CD4+ cells and mitogen-induced IL-2 secreting cells and IL-2 production were significantly lower in schizophrenic subjects than in the normal controls. There was significantly positive correlation between CD4+ cells and IL-2 production in normal controls but not in patients. These findings suggest that immune disturbance may be present in schizophrenic patients. The lower in vitro IL-2 production is probably related to the decreased number of T-cells that secret IL-2, as well as to the intrinsic disorder of the patients' T cells.