1,25-Dihydroxy vitamin D3 downregulates pro-inflammatory cytokine response in pulmonary tuberculosis.

1,25-Dihydroxy vitamin D3 [1,25(OH)2D3] is a potent immunomodulator and regulates various immune responses to Mycobacterium tuberculosis (Mtb). The present study aimed to understand the effect of 1,25(OH)2D3 on pro-inflammatory cytokine response to Mtb antigen. Peripheral blood mononuclear cells from 42 healthy controls (HCs) and 42 pulmonary tuberculosis (PTB) patients were cultured with culture filtrate antigen (CFA) of Mtb with and without 1,25(OH)2D3 at 10(-7)M concentration for 72 h. The levels of IL-1α, IL-1β, TNF-α, TNF-β, IL-17 and IL-23 were estimated in the culture supernatants by ELISA. 1,25(OH)2D3 significantly suppressed all the CFA induced pro-inflammatory cytokines (p<0.05) studied except IL-1β in both HCs and PTB patients. Among the PTB patients, the observed suppression was visible both in patients with and without cavitary tuberculosis. The present study results suggest that 1,25(OH)2D3 downregulates the production of pro-inflammatory cytokines and may control the exacerbated inflammatory response that may protect the host from excessive tissue damage at the site of infection.