Will a simple, daily dose of sunshine correct the majority of our immune problems? Vitamin D deficiency has been associated with asthma, IgE levels, atopy, and obesity. Now new research has associated vitamin D deficiency with allergic bronchopulmonary aspergillosis (ABPA), which is, in turn, associated with Aspergillus fumigatus colonization in cystic fibrosis (CF) patients; however, only a small percentage of affected CF patients develop ABPA.
Kreindler et al. (J Clin Invest 2010, doi:10.1172/JCI42388) investigated this observation by comparing the Th2 profiles of ABPA CF patients and colonized, non-ABPA CF patients. They found that ABPA CF patients were characterized by a TSLP- & OX40L-driven Th2 environment. In contrast, non-ABPA CF patients did not have an excessive Th2 response and had high levels of TGF-β producing Tregs. Since vitamin D has been associated with Treg development, the authors assessed vitamin D levels in both groups; they found that ABPA patients were significantly deficient relative to the non-ABPA group. They went on to demonstrate that vitamin D deficiency lowered Tgfb mRNA and raised OX40L levels in mice. Treatment with vitamin D reversed these conditions.
Kreindler and coauthors suggested that their data demonstrated that vitamin D increases the proportion of TGF-β to OX40L favoring the induction of Tregs rather than Th2 cells.
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