SERUM INTERLEUKIN-6 CONCENTRATION IN SCHIZOPHRENIA - ELEVATION ASSOCIATED WITH DURATION OF ILLNESS

Using an enzyme immunoassay (ELISA), we measured serum interleukin-6 ( IL-6) concentration in 128 schizophrenic patients (24 of whom were nev er medicated) and in 110 normal control subjects. Mean serum IL-6 conc entration was significantly higher in the schizophrenic patients as co mpared with the control subjects (p = 0.009). Comparisons within the p atient group revealed that serum IL-6 was significantly correlated wit h duration of illness (r = 0.32, p = 0.0004). After covariation for du ration of illness, there was no relationship between IL-6 levels and t he production of autoantibodies, clinical state, or medication status. Thus, elevated serum IL-6 levels in schizophrenia develop during the course of illness and may be related to treatment or to disease progre ssion.