These findings may be related to the immune modulating role of vitamin D, since in vitro studies have demonstrated that calcitriol stimulates monocyte to macrophage differentiation, reduces the production of proinflammatory factors by activated macrophages, and upregulates the expression of several antimicrobial peptides (e.g., CAMP and β-defensins) by innate immune cells, thus enhancing the initial response to infection and protecting the organism from excessive cytokine activation [34, 35]. The gene discussed is CAMP; the disease is infection.