No association between vitamin D and β‐cell autoimmunity in Finnish and Estonian children. Issue 8 (November 2014)

• Record Type: Journal Article
• Authors: Reinert‐Hartwall, L.; Honkanen, J.; Härkönen, T.; Ilonen, J.; Simell, O.; Peet, A.; Tillmann, V.; Lamberg‐Allardt, C.; Virtanen, S. M.; Knip, M.; Vaarala, O.; The DIABIMMUNE Study Group
• Is Part Of: Diabetes/metabolism research and reviews. Volume 30:Issue 8(2014:Nov.)
• Page Start: 749
• Page End: 760
• Publication Date: 2014-11
• Subjects: Diabetes -- Periodicals; Metabolism -- Periodicals; 616.642
• DOI: 10.1002/dmrr.2550
• Languages: English
• ISSNs: 1520-7552

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <sec id="dmrr2550-sec-0001" sec-type="section"> <title>Background</title> <p>Vitamin D has immunomodulatory properties, such as regulation of <italic>FOXP3</italic> expression and regulatory T‐cell activity. Our aim was to investigate whether plasma 25‐hydroxyvitamin D [25(OH)D] concentrations associate with the development of β‐cell autoimmunity and the transcriptional activity of <italic>FOXP3</italic> or vitamin D3 convertase gene (<italic>CYP27B1</italic>) in CD4+ memory T cells.</p> </sec> <sec id="dmrr2550-sec-0002" sec-type="section"> <title>Methods</title> <p>We studied 83 Finnish and 32 Estonian children participating in the DIABIMMUNE and DIPP studies. Twenty‐nine Finnish and six Estonian children tested positive for at least one diabetes‐associated autoantibody. The plasma concentrations of 25(OH)D and 1, 25(OH)<sub>2</sub>D were analysed with an enzyme immunoassay. Gene expression of <italic>FOXP3</italic> and <italic>CYP27B1</italic> in the isolated CD4+ memory T cells was studied with reverse transcription quantitative polymerase chain reaction.</p> </sec> <sec id="dmrr2550-sec-0003" sec-type="section"> <title>Results</title> <p>Vitamin D status did not differ between subjects positive and negative for β‐cell autoantibodies. Finnish children had higher vitamin D status than Estonian children (<italic>p</italic> < 0.001). <italic>FOXP3</italic> expression was higher in Estonian CD4+ memory T‐cell samples than in Finnish samples (<italic>p</italic> < 0.01) even when including in both groups only children with serum 25(OH)D concentrations in the range of 50–80 nmol/L (<italic>p</italic> < 0.001).</p> </sec> <sec id="dmrr2550-sec-0004" sec-type="section"> <title>Conclusions</title> <p>These findings do not support a crucial role of circulating 25(OH)D as a regulator of β‐cell autoimmunity or <italic>FOXP3</italic> expression. Copyright © 2014 John Wiley & Sons, Ltd.</p> </sec> </abstract>