Vitamin D for mold allergies

Mold allergies are a vexing problem for many whose immune system is compromised, especially when exposure at home or work is unavoidable. Research just published in The Journal of Clinical Investigation provides welcome evidence that Vitamin D substantially reduces the allergic response to mold and promotes tolerance.

"The development of Th2 responses, as in asthma and allergic bronchopulmonary aspergillosis (ABPA), is driven by both genetic and environmental factors. Mechanistically, inhaled allergens are presented by lung DCs [dendritic cells] to naive T cells, which leads to induction of allergen-specific Th2 cells...In patients with ABPA, immunological responses to a variety of A. fumigatus [mold] antigens result in a heightened Th2 response and an elevated IgE level."

To determine what determines a Th2 allergic response as opposed to Treg (regulatory T cell) tolerance the authors compared a groups of cystic fibrosis patients suffering from ABPA and and another group without it by measuring several key immune factors. Their findings have great practical significance:

"Furthermore, we discovered that ABPA correlated with vitamin D deficiency, and supplementation with vitamin D potentiated Treg-mediated regulation of Th2 reactivity...Patients with ABPA had significantly lower 25-OH vitamin D (the major circulating form of vitamin D3) levels compared with non-ABPA controls, and the mean level was significantly below the recommended level of 30 ng/ml in CF."

Any doctor who is diligently testing their patients for Vitamin D insufficiency knows that suboptimal levels are surprisingly common. Could this have something to do with relative malnutrition, time of year or geographic location? The authors' data says "no":

"Notably, there was no significant difference in BMI or vitamin A and E levels between ABPA and non-ABPA patients, suggesting that the relative vitamin D deficiency was not associated with relative malnutrition... To exclude potential environmental/geographical differences in our cohort, we used geographical information systems (GIS) mapping to determine whether there was geographical clustering of ABPA patients versus non-ABPA patients; however, this analysis did not identify significant clustering... Finally, there was no significant difference in terms of month of accrual in the study between the ABPA or non-ABPA cohort... Taken together, these findings strongly suggest that the relative 25-OH vitamin D deficiency observed in ABPA patients was not a surrogate marker of another variable..."

This research adds to the immense body of evidence regarding the importance of Vitamin D for immune regulati0n and the treatment of allergies and autoimmune diseases (along with a host of other conditions). How can you reliably know your Vitamin D status? Ask your doctor for a 25-hydroxy vitamin D blood test, and look for a level closer to the middle of the typical lab's reference range rather than toward the bottom.