CYP27B1 and infection: The immunomodulatory mechanisms of vitamin D include enhancing phagocytosis and chemotaxis of innate immune cells such as macrophages and monocytes, thereby improving pathogen clearance (28); inducing dendritic cell tolerance through the expression of CYP27B1, which enhances localized concentrations of active vitamin D at infection sites (29); and integrating with pattern recognition receptors (PRRs) to detect microbial signals and activate downstream infection-fighting pathways (30).