Document Detail


Autoimmune Predisposition in Down Syndrome May Result from a Partial Central Tolerance Failure due to Insufficient Intrathymic Expression of AIRE and Peripheral Antigens.
MedLine Citation:
PMID:  25217160     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Down syndrome (DS), or trisomy of chromosome 21, is the most common genetic disorder associated with autoimmune diseases. Autoimmune regulator protein (AIRE), a transcription factor located on chromosome 21, plays a crucial role in autoimmunity by regulating promiscuous gene expression (pGE). To investigate if autoimmunity in DS is promoted by the reduction of pGE owing to dysregulation of AIRE, we assessed the expression of AIRE and of several peripheral tissue-restricted Ag genes by quantitative PCR in thymus samples from 19 DS subjects and 21 euploid controls. Strikingly, despite the 21 trisomy, AIRE expression was significantly reduced by 2-fold in DS thymuses compared with controls, which was also confirmed by fluorescent microscopy. Allele-specific quantification of intrathymic AIRE showed that despite its lower expression, the three copies are expressed. More importantly, decreased expression of AIRE was accompanied by a reduction of pGE because expression of tissue-restricted Ags, CHRNA1, GAD1, PLP1, KLK3, SAG, TG, and TSHR, was reduced. Of interest, thyroid dysfunction (10 cases of hypothyroidism and 1 of Graves disease) developed in 11 of 19 (57.9%) of the DS individuals and in none of the 21 controls. The thymuses of these DS individuals contained significantly lower levels of AIRE and thyroglobulin, to which tolerance is typically lost in autoimmune thyroiditis leading to hypothyroidism. Our findings provide strong evidence for the fundamental role of AIRE and pGE, namely, central tolerance, in the predisposition to autoimmunity of DS individuals.
Authors:
Mireia Giménez-Barcons; Anna Casteràs; Maria Del Pilar Armengol; Eduard Porta; Paula A Correa; Ana Marín; Ricardo Pujol-Borrell; Roger Colobran
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-9-12
Journal Detail:
Title:  Journal of immunology (Baltimore, Md. : 1950)     Volume:  -     ISSN:  1550-6606     ISO Abbreviation:  J. Immunol.     Publication Date:  2014 Sep 
Date Detail:
Created Date:  2014-9-13     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985117R     Medline TA:  J Immunol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2014 by The American Association of Immunologists, Inc.
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