gamma delta T cells develop independently of Aire

Mutations in the transcriptional regulator Aire disrupt thymic alpha beta T cell selection, causing in humans Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). However, it is not known whether Aire is needed for normal gamma delta T cell development. We show that Aire(-/-) mice have a normal frequency of gamma delta T cells, with TCR repertoire comparable to that of wild-type mice, and normal amount of TCR C delta mRNA in ileum and skin. gamma delta T cells did not express increased amounts of CD25 or display hyperproliferation, and were not involved in pathological salivary gland infiltrates. Lastly, the frequency of circulating gamma delta T cells was similar in APECED patients and healthy controls. These data indicate that gamma delta T cells develop independently of Aire and are unlikely to have a significant pathogenetic or protective role in APECED. The antigens responsible for gamma delta and alpha beta T cell selection are thus probably largely different. (C) 2009 Elsevier Inc. All rights reserved.