Vitamin D and immune function: an overview.

Authors:
Martin Hewison

Proc Nutr Soc 2012 Feb 18;71(1):50-61. Epub 2011 Aug 18.

UCLA and Orthopaedic Hospital Department of Orthopaedic Surgery and the Orthopaedic Hospital Research Center, David Geffen School of Medicine at UCLA, 615 Charles E. Young, Los Angeles, CA 90095, USA.

Immunomodulatory actions of vitamin D have been recognised for over a quarter of a century, but it is only in the last few years that the significance of this to normal human physiology has become apparent. Two key factors have underpinned this revised perspective. Firstly, there are increasing data linking vitamin insufficiency with prevalent immune disorders. Improved awareness of low circulating levels of precursor 25-hydroxyvitamin D in populations across the globe has prompted epidemiological investigations of health problems associated with vitamin D insufficiency. Prominent among these are autoimmune diseases such as multiple sclerosis, type 1 diabetes and Crohn's disease, but more recent studies indicate that infections such as tuberculosis may also be linked to low 25-hydroxyvitamin D levels. The second factor expanding the link between vitamin D and the immune system is our improved knowledge of the mechanisms that facilitate this association. It is now clear that cells from the immune system contain all the machinery needed to convert 25-hydroxyvitamin D to active 1,25-dihydroxyvitamin D, and for subsequent responses to 1,25-dihydroxyvitamin D. Mechanisms such as this are important for promoting antimicrobial responses to pathogens in macrophages, and for regulating the maturation of antigen-presenting dendritic cells. The latter may be a key pathway by which vitamin D controls T-lymphocyte (T-cell) function. However, T-cells also exhibit direct responses to 1,25-dihydroxyvitamin D, notably the development of suppressor regulatory T-cells. Collectively these observations suggest that vitamin D is a key factor linking innate and adaptive immunity, and both of these functions may be compromised under conditions of vitamin D insufficiency.

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http://dx.doi.org/10.1017/S0029665111001650DOI Listing
February 2012
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(Supplied by CrossRef)
Dysfunction of the vitamin D endocrine system as common cause for multiple malignant and other chronic diseases
Peterlik et al.
Anticancer Res 2006
Immunosuppressive actions of 1,25-dihydroxyvitamin D3: Preferential inhibition of Th1 functions
Lemire et al.
J Nutr 1995

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