The effects of vitamin K1 and vitamin K2 on the proliferation, cytokine production and regulatory T‐cell frequency in peripheral blood mononuclear cells of paediatric atopic dermatitis patients

: We estimated the pharmacological efficacy of vitamin K1 (VK1 ) and VK2 on the mitogen-activated peripheral blood mononuclear cells (PBMCs) of paediatric atopic dermatitis (AD) patients. VK2 suppressed the in vitro proliferation of T-cell mitogen-activated PBMCs of AD patients. In contrast, VK1 had little effect on the PBMC proliferation. The IL-2 production from the activated PBMCs of AD patients significantly increased (P < .05), while the production significantly decreased by 100 μmol L-1 VK2 (P < .01). In addition, 100 μmol L-1 VK2 reduced the percentage of CD4+ and CD4+CD25+ cells in PBMCs. These results suggest that VK2 can modulate T-cell function in PBMCs of AD patients.