Effect of vitamin D3 on chemokine levels and regulatory T-cells in pulmonary tuberculosis.

1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] the active form of vitamin D3 acts as an immunomodulator in various immune cells. The present study is aimed to study the effect of 1,25(OH)2D3 on chemokine levels and regulatory T-cells in 51 healthy controls (HCs) and 50 pulmonary tuberculosis (PTB) patients. Peripheral blood mononuclear cells were cultured with culture filtrate antigen (CFA) of Mycobacterium tuberculosis in the presence or absence of 1,25(OH)2D3 at 10(-7) M concentration for 72 h and the percentage positive regulatory T-cell subsets were studied using flow cytometry. The chemokine levels were estimated in the culture supernatants by ELISA. 1,25(OH)2D3 significantly upregulated the frequency of regulatory T-cell subsets while suppressed the production of chemokine levels in CFA stimulated cultures of HCs and PTB patients (p<0.05). Correlation analysis revealed a significant negative correlation between CD4+Foxp3+ regulatory T-cells and MCP-1, MIP-1β and IP-10 in CFA stimulated with 1,25(OH)2D3 treated cells (p<0.05). The results suggested that 1,25(OH)2D3 upregulated regulatory T-cells and act as anti-inflammatory by downregulating chemokine levels which could be beneficial to protect the host from inflammation and tissue damage during infection.