Elevated interleukin-6 in schizophrenia

Interleukin 6 (IL-6) levels have been shown to be increased in a number of autoimmune disorders and have recently been shown to be elevated in the ser um of schizophrenic patients. Given the involvement of the CNS in schizophr enia, levels of interleukin-6 in the CSF are also of interest. Thus, we exa mined levels of both CSF and serum IL-6 concomitantly to determine if these levels were different from control values. In addition, we examined these measures in patients both on and off antipsychotic drugs to determine if an y medication or exacerbation effects may account for the difference from co ntrols. CSF IL-6 was measured by ELISA in 61 drug-free male schizophrenic ( DSM-IIIR) patients and 25 well-screened healthy male control subjects. Seru m IL-6 was measured in 43 of the 61 patients, and in 16 control subjects. S erum IL-6 was significantly higher in the schizophrenic patients compared t o control subjects. CSF IL-6 was also higher in the patients, but the diffe rence was not statistically significant. Paired data showed no medication o r exacerbation effects on CSF IL-6, but plasma IL-6 significantly decreased in patients that experienced an exacerbation after medication withdrawal. The results indicate that IL-6 levels may be altered in schizophrenia. The relative decrease in exacerbated patients following haloperidol withdrawal may be indicative of a compensatory response of plasma IL-6 levels to relap se. (C) 1999 Published by Elsevier Science Ireland Ltd. All rights reserved .