Vitamin D and the Immune System from the Nephrologist's Viewpoint

Figure 2

Vitamin D and innate immune system. 1,25(OH)₂D₃ promotes innate immunity when macrophage (M_Φ) is activated by TLRs; CYP27B1 is induced enabling the macrophage to produce 1,25(OH)₂D₃, which subsequently gives rise to cathelicidin. On the other hand, 1,25(OH)₂D₃ inhibits the expression of costimulatory molecules (DC40, CD80/86) and major histocompatibility complex class II (MHC II) on the surface of monocyte-derived dendritic cell (DC) and inhibits the production of inflammatory cytokines, such as interleukin-12 (IL-12).