Clozapine-Induced Increase in Plasma Levels of Soluble Interleukin-2 Receptors

Increased levels of soluble interleukin-2 receptor (SIL-2R) have been reported in schizophrenia and are thought to indicate prior or current activation of T lymphocytes.¹,²Clozapine is an antipsychotic drug known for an associated high risk for agranulocytosis, and immunological processes have been suggested as possible pathophysiological factors (for an overview see the article by Alvir et al³). Recently, it has been reported that long-term clozapine treatment of highly variable duration (33 to 194 days) increased plasma SIL-2R levels.⁴A single dose of the typical neuroleptic haloperidol, on the other hand, did not influence plasma SIL-2R levels of this cytokine receptor in healthy controls.⁵ We report herein on the time course of plasma SIL-2R levels evaluated prospectively during 6 weeks of treatment with clozapine. Ten patients (three women and seven men; mean±SD age, 31.8±5.5 years) who fulfilledDSM-III-R⁶criteria for a schizophrenic disorder and who had