Vitamin K2 immunosuppressive effect on pediatric patients with atopic dermatitis.

BACKGROUND:Over 20 kinds of steroids, tacrolimus ointments, and cyclosporine capsules are usually recommended for the treatment of atopic dermatitis (AD), depending on the symptoms of patients. However, several side effects sometimes occur with the extensive use of these agents for the treatment of pediatric AD patients. The purpose of this study was to explore whether vitamin K2 could be a new immunosuppressive candidate for pediatric patients with AD. METHODS:The immunosuppressive efficacy of vitamin K2 was evaluated through a cell-culture procedure using mitogen-activated peripheral blood mononuclear cells (PBMCs) obtained from pediatric AD patients. RESULTS:The mean (SD) IC50 value of vitamin K2 for the proliferation of concanavalin A-activated PBMCs was 15.37 (30.05) μmol/L, while the value for tacrolimus was 0.10 (0.28) ng/mL (0.12 (0.35) nmol/L). There was a significant correlation between the IC50 values for vitamin K2 and those for tacrolimus (P = 0.0001, r = 0.8871). However, there was no significant correlation between the IC50 values of vitamin K2 and those of cyclosporine A or methylprednisolone. A significant correlation between the IC50 values of vitamin K2 or tacrolimus and blood eosinophil counts (P = 0.0099, r = 0.7086 and P = 0.0032, r = 0.7722, respectively) was observed. CONCLUSION:Vitamin K2 -inhibited T-cell mitogen stimulated proliferation of PBMCs from pediatric AD patients in a dose-dependent manner. The PBMCs from pediatric AD patients were more sensitive to the immunosuppressive efficacy of vitamin K2 than the PBMCs from healthy subjects. The individual immunosuppressive pharmacological efficacy of vitamin K2 and of tacrolimus could be inferred from the blood eosinophil count of pediatric AD patients.