Calcitriol reduces eosinophil cytolysis and release of cytotoxic granules in vitro

Background Epidemiological studies show a strong correlation between vitamin D deficiency and asthma severity. Genetic studies have identified vitamin D receptor polymorphisms as a risk factor for asthma in diverse human populations. Calcitriol (1,25-dihydroxyvitamin D3), the physiologically active metabolite of mammalian vitamin D, is able to modulate receptor and cytokine expression as well as cell differentiation and maturation of various leukocytes in an anti-inflammatory manner. Despite the role of eosinophils in allergic asthma pathology, little is known about the effects of calcitriol on eosinophil biology. Calcitriol has a direct modulatory effect on eosinophil survival and effector functions in vitro.