Vitamin D inhibits IgE production

An increased incidence of allergic diseases has been associated with vitamin D deficiency. Calcitriol, the active form of vitamin D, inhibits ε germline transcription, a prerequisite for IgE production.

Calcitriol-activated vitamin D receptor (VDR) binds together with retinoid X receptor α to the Iε region (ε germline gene promoter (Iε)). The heterodimer interacts with silencing mediator for retinoid and thyroid hormone receptors, which recruits histone deacetylases (HDAC). Update: HDAC1 and HDAC2 expression is not downregulated in severe asthma - contradicting previous studies (http://goo.gl/CHMm7).

The inhibition of IgE production by calcitriol is mediated through the VDR-corepressor complex affecting chromatin compacting around the Iε region.

The level of IgE increases during childhood until about 10 years of age. At age 10, the total IgE reaches a value that is typically maintained throughout adult life.

References:

Vitamin D receptor binds to the ε germline gene promoter and exhibits transrepressive activity.
Milovanovic M, Heine G, Hallatschek W, Opitz B, Radbruch A, Worm M. J Allergy Clin Immunol. 2010 Oct 4. [Epub ahead of print]

Cord-blood level of vit D had inverse association with risk of resp infection and childhood wheezing, but not asthma. Pediatrics, 2010. http://goo.gl/Rjnl5

Bacterial components plus vitamin D: The ultimate solution to the asthma (autoimmune disease) epidemic? JACI, 2011 (PDF).

Low vitamin D at age 6 was a predictor of atopy and asthma at 14 http://goo.gl/LJCmX
Both low and high levels of cord blood 25(OH) vitamin D were associated with increased aeroallergen sensitization. JACI, 2011.
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