Decreased Interleukin-2 Production in Korean Schizophrenic Patients

Background: It has been postulated that autoimmune process may play a role in the pathogenesis of symptoms in some schizophrenic patients. Findings of altered interleukin (IL) regulation have been regarded as additional proof that schizophrenia has an autoimmunological background. Methods: Sixteen patients who fulfilled DSM-IV criteria for schizophrenia and who were drug free for at least six months and the same number of age- and sex-matched controls were recruited. The severity of symptoms in schizophrenia was assessed by BPRS. Phytohemagglutinin (PHA)-stimulated production and serum level of IL-1β, IL-2, and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). Results: There was a significant decrease of IL-2 production (p< .01) in schizophrenic patients and a significant increase of IL-2 serum level (p< .01). No significant difference of IL-1β and IL-6 was found. Some patients and controls had measurable serum level of IL-1β and IL-6. No significant correlation between production and serum level of IL-1β, -2, -6 and age, duration of illness, and BPRS score in schizophrenics was found. Conclusions: This is the first study to describe a decrease of IL-2 production and increase of IL-2 serum level in non-Caucasian schizophrenic patients. These findings are further evidence that autoimmune process is present, regardless of ethnic origin, in some schizophrenic patients.