Regulation of macrophage immune responses by antipsychotic drugs.

Antipsychotic drugs (APDs) have been used to ease clinical psychotic symptoms. APDs have also been recently discovered to induce immune regulation. Our previous studies found that atypical APDs risperidone and clozapine could inhibit INF-γ production of human peripheral blood mononuclear cells (PBMC) and could inhibit Th1 differentiation. This study further investigates APD effects on monocyte-derived macrophages, which are the major antigen-presenting cells in PBMC. Our data suggest that adhesion, phagocytosis and reactive oxygen species production of monocytic cell lines would be inhibited by haloperidol, risperidone or clozapine. Also, that APDs inhibited the production of LPS-stimulated macrophages IL-6 and IL-8 suggests that risperidone and clozapine may inhibit inflammation. We further discovered that risperidone and clozapine could inhibit IL-12 production and increase IL-10 production of LPS-stimulated macrophages. These results indicated that risperidone and clozapine could inhibit Th1 differentiation not only by increasing INF-γ production of PBMC but by inhibiting the release of Th1-inducing cytokines and increasing Th2-inducing cytokines of LPS-stimulated macrophages to modulate and regulate immune responses.