Vitamin D: immunomodulation of asthma, allergic rhinitis, and chronic rhinosinusitisAkbar, Nadeem A; Zacharek, Mark ACurrent Opinion in Otolaryngology & Head & Neck Surgery: June 2011 - Volume 19 - Issue 3 - p 224–228 doi: 10.1097/MOO.0b013e3283465687 Allergy: Edited by Berrylin Ferguson Abstract Author Information Purpose of review: To discuss the role of vitamin D in asthma, allergic rhinitis, and chronic rhinosinusitis (CRS). Recent findings: Over the last several years, the role of vitamin D in immunomodulation has been studied and shown to have a significant impact on immune function. A causal relationship exists between vitamin D function and innate and adaptive immunity to infections. The mechanisms underlying vitamin D immune actions could be attributed to a paracrine feedback loop that reduces inflammation as well as influencing the differentiation fate of activated CD4 T cells, or the enhancement of suppressor T-cell function; indeed, a combination of these factors may underlie the actions of vitamin D. Summary: Recent findings on the function of vitamin D may explain aspects of the pathophysiology of allergic rhinitis and CRS and may help direct future interventions and treatment of these diseases. Department of Otolaryngology/Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan, USA Correspondence to Mark Zacharek, MD, FACS, FAAOA, Clinical Associate Professor of Otorhinolaryngology, Department of Otolaryngology/Head and Neck Surgery, University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI 48109, USA Tel: +1 734 232 0120; fax: +1 734 936 9625; e-mail: firstname.lastname@example.org © 2011 Lippincott Williams & Wilkins, Inc.