VDR and vitamin D deficiency: Vitamin D restricts M. tuberculosis growth in macrophages through the production of the anti-microbial peptide, cathelicidin [8].Many studies showed an association between vitamin D deficiency and certain diseases such as systemic lupus erythematosus [9], diabetes mellitus [10], tuberculosis [11], etc. During a tuberculosis infection, vitamin D binds to VDR in macrophages, and this binging activates synthesis of the antimicrobial peptide cathelicidin, which restricts M. tuberculosis intracellular growth in macrophages [12], and eliminates Mycobacterium tuberculosis in phagolysosomes [13].