1,25-Dihydroxyvitamin D3 modulates T cell differentiation and impacts on the production of cytokines from Chinese Han patients with early rheumatoid arthritis.

To study the effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on the differentiation of T cells and the levels of cytokines in patients with early rheumatoid arthritis (eRA). The levels of Th1, Th2, Th17, and Treg cells were detected with BDFACS Calibur flow cytometer. The expression of IFN-ɤ, TNF-α, IL-2, IL-4, IL-6, IL-10, IL-17, and IL-22 was examined in 54 patients with eRA using a cytometric bead array (CBA). After 72 h of incubation of PBMCs from eRA patients with 1,25(OH)2D3, the levels of IFN-ɤ, TNF-α, IL-2, IL-6, and IL-17 significantly decreased compared to those of the control. 1,25(OH)2D3 had no significantly impact on the levels of IL-4, IL-10, and IL-22. The proportion of Th17 and the ratio of Th17/Treg significantly decreased in 1,25(OH)2D3-treated groups compared to those of the control. 1,25(OH)2D3 had no significantly impact on the proportion of Th1, Th2, Treg, and the ratio of Th1/Th2. Although no statistically significant difference was observed, proportion of Th1 was decreased after 1,25(OH)2D3 treatment compared with anti-CD3/CD28 only. The present study demonstrated that 1,25(OH)2D3 inhibited the synthesis of specific cytokines: Th1 (IFN-ɤ) and Th17 (IL-17, IL-22, IL-6, TNF-α) might upregulated Th2 cytokine (IL-4), which indicated the possible immunoregulatory roles and bone-sparing effects of 1,25(OH)2D3 in eRA through modulation of the Th1 and Th17 cytokine balance.