TLR1 and Sepsis: The role of vitamin D in sepsis and critically illness has recently received attention since the discovery that Mycobacterium tuberculosis activation of the toll-like receptors (TLR)1/2 pathway further engages a vitamin D-dependent intracellular signaling that results in the upregulation of 1,25(OH)2D synthesis, leading to production of LL-37 (also known as cathelicidin) and enhanced monocyte antimicrobial activity [20].