Acomparison of vitamin D and cathelicidin (LL-37) levels between patients with active TB and their healthy contacts in a high HIV prevalence setting:

Abstract

Vitamin D(25-OHvitaminD)is afat-soluble vitamin that appears to play an important role in innate and acquired cellular immune responses to human infection with members of the Mycobacterium tuberculosis complex. Both ex vivo and in vivo studies have indicated that vitamin D may enhance the clearance of M. tuberculosis.1-5 Vitamin D stimulates macrophage production of a pore-forming peptide molecule called cathelicidin (LL37) and plays an important role in effecting phagocytosis of M. tuberculosis. LL-37 is raised in patients infected with intracellular pathogens, including active TB disease.6 Torres-Juarez et al. demonstrated the immune modulatory effect of exogenous LL37 by decreasing the production of TNF-alpha and IL-17 and inducing the production of IL-10, which is anti-inflamatory.7 The regions of the world with the highest burden of TB mirror those with the highest burden of vitamin D deficiency. Studies from Asia and Europe have shown an association between vitamin D deficiency and susceptibility to TB.8-10 Conventional assumptions that vitamin D deficiency in sub-Saharan Africa may not be an important factor in TB patients require further study. We performed a prospective observational case-control study to determinelevelsofvitaminDandLL-37inZambianadultpatientswith TB and compare them with healthy controls.