OBJECTIVETo investigate the effect of FK506 on cytokine secretions in whole blood from healthy individuals.

METHODSBlood samples collected from healthy volunteers were co-cultured with different concentrations of FK506 and stimulated with PMA and IONO. The concentrations of 8 cytokines including IL-2, IL-6, IL-12, IL-17, IFN-gamma, TNF-alpha, GM-CSF and G-CSF were detected by Bio-Plex suspension system.

RESULTSCompared with the control group, high-concentration FK506 (20 ng/ml) significantly inhibited the secretions of IL-2, IL-6, IL-12, IL-17, IFN-gamma, TNF-alpha, GM-CSF and G-CSF. At a moderate concentration (5 ng/ml), FK506 inhibited the secretion of GM-CSF significantly.

CONCLUSIONFK506 effectively inhibits the secretion of proinflammatory cytokines including IL-6, IFN-gamma and TNF-alpha and also the secretion of IL-2, IL-12, IL-17, GM-CSF and G-CSF. FK506 might play the role of immunosuppression by inhibiting the production of these cytokines by the immune cells. Monitoring the levels of these cytokines might be a potential method for evaluating the adequacy of FK506 doses administered.