INCREASES IN CSF LEVELS OF INTERLEUKIN-2 IN SCHIZOPHRENIA - EFFECTS OF RECURRENCE OF PSYCHOSIS AND MEDICATION STATUS

Objective: Interleukin-2, traditionally viewed as solely involved in i mmunological events, has recently been shown to exert profound effects on the development and regulation of the central nervous system. This study examined the relationships between interleukin-2 in the CSF and plasma of schizophrenic patients and clinical measures, including rel apse and medication status. Plasma and CSF interleukin-1 alpha levels were also measured to ascertain the specificity of changes in cytokine levels. Method: Seventy-nine physically healthy male patients with sc hizophrenia (DSM-III-R) received diagnostic evaluation and behavioral ratings. Haloperidol treatment was withdrawn for up to 6 weeks and pat ients were evaluated for symptom recurrence. CSF and plasma were obtai ned by established procedures before haloperidol withdrawal (N=79) and after (N=64). Results: CSF levels of interleukin-1 alpha decreased si gnificantly after haloperidol withdrawal but showed no relation to cli nical status. In contrast, levels of CSF interleukin-2 were associated with recurrence of psychotic symptoms. Relapse-prone patients, examin ed both while medicated and after drug withdrawal, had significantly h igher levels of CSF interleukin-2 than patients who did not relapse. C SF interleukin-2 level during haloperidol treatment was a significant predictor of worsening in psychosis. Conclusions: Levels of interleuki n-2, a molecule that plays both neurodevelopmental and neuroregulatory roles, may have a rob in relapse in schizophrenia. Levels of CSF inte rleukin-2 appear to be affected by relapse mechanisms, while periphera l blood levels are not. These changes are specific to interleukin-2, s ince levels of interleukin-1 alpha were affected by medication withdra wal but not by change in clinical state.