T helper 1 inhibitor TAK-603 inhibits IFN-gamma and IL-12 production with no effect on IL-18: an observation in sarcoidosis patients.

BACKGROUND AND AIM: Sarcoidosis is immunologically characterized by highly enhanced Th1 responses in active stage. TAK-603 is a new quinoline derivative, which selectively suppresses Th1 cytokine production. Thus, the present study was designed to investigate whether TAK-603 ameliorates excess IFN-gamma production in active sarcoidosis. METHODS: We evaluated inhibitory effects of TAK-603 on IFN-gamma, IL-12 and IL-18 production in stimulated bronchoalveolar lavage (BAL) fluid cells and peripheral blood mononuclear cells (PBMCs) of sarcoidosis patients and healthy subjects. RESULTS: TAK-603 inhibited IFN-gamma production in stimulated BAL fluid cells and PBMCs of sarcoidosis patients and healthy subjects. TAK-603 inhibited IL-12 production in stimulated BAL fluid cells of sarcoidosis patients and healthy subjects. TAK-603 tended to inhibit IL-12 production in stimulated PBMCs of sarcoidosis patients and healthy subjects. However, TAK-603 did not affect IL-18 production in stimulated BAL fluid cells and PBMCs. TAK-603 did not affect TNF-alpha production in stimulated BAL fluid cells of sarcoidosis patients. TAK-603 inhibited IL-12 production in stimulated blood monocytes of healthy subjects, whereas IL-18 was increased by treatment with TAK-603. TAK-603 inhibited IFN-gamma production in PHA-stimulated blood T lymphocytes of healthy subjects with stimulation of IL-12 or a combination of IL-12 and IL-18. TAK-603 did not increase IL-10 or TGF-beta1 production in LPS-stimulated BAL fluid cells of sarcoidosis patients. CONCLUSIONS: TAK-603 inhibits IFN-gamma production in activated T lymphocytes and IL-12 production in activated monocytes/macrophages independently of increased production of IL-10 and TGF-beta1. TAK-603 may ameliorate excess IFN-gamma production and be a therapeutic tool for refractory sarcoidosis.