Vitamin D May Support Immunity

According to a new study, vitamin D may reduce the development of an allergic respiratory reaction after exposure to the mold Aspergillus. Mold allergies generally occur all year and are triggered by inhalation of the fungal spores. The American Academy of Allergy, Asthma and Immunology reports that allergic diseases affect as many as 40 to 50 million Americans.

This new study evaluated the Th2 (Type 2 - Helper T-lymphocyte) response to Aspergillus fumigatus, which is a type of immune system response that occurs with allergic reactions. In this study, subjects with cystic fibrosis were evaluated due to the high rate of allergic bronchopulmonary aspergillosisin this population. Subjects with or without an allergic response to Aspergillus fumigatus were evaluated to compare differences between these two groups, including serum vitamin D levels.

The study results showed that the subjects with a heightened Th2 response to Aspergillus antigen had lower mean serum vitamin D levels. The increased Th2 response was associated with a co-stimulatory molecule known as OX40 ligand, which is a critical molecule in the development of the Th2 allergic response, and a decrease in the cells expressing the chemical mediator called transforming growth factor (TGF)-beta, which is associated with the development of immune tolerance to allergenic proteins.

In vitro treatment with vitamin D3 resulted in a decrease in the OX40 ligand and an increase in cells expressing TGF-beta. Additionally, the researchers showed that in vitro, vitamin D3 treatment reduced the Th2 response by T-lymphocytes from the subjects with Aspergillus allergies.

The study authors concluded that these data provide rationale for an additional trial of vitamin D to further determine its role in supporting immunity in allergic bronchopulmonary aspergillosis in patients with cystic fibrosis.

Reference:

Kreindler JL, Steele C, Nguyen N, Chan YR, Pilewski JM, Alcorn JF, Vyas YM, Aujla SJ, Finelli P, Blanchard M, Zeigler SF, Logar A, Hartigan E, Kurs-Lasky M, Rockette H, Ray A, Kolls JK. Vitamin D3 attenuates Th2 responses to Aspergillus fumigatus mounted by CD4+ T cells from cystic fibrosis patients with allergic bronchopulmonary aspergillosis. J Clin Invest. 2010 Aug 16. Published Online Ahead of Print.