T-cell receptor α chain V region polymorphism linked to primary autoimmune hypothyroidism but not Graves' Disease

T-cell receptor α- and ß-chain polymorphisms have been investigated in patients with autoimmune thyroid disease. Using a cDNA probe for the T-cell receptor α chain, a 1.4-kb V α Taq I restriction fragment was found in 25 of 33 patients with autoimmune hypothyroidism compared to 33 of 61 control subjects ( p < 0.05) and 16 of 43 patients with Graves' disease ( p < 0.001 compared to patients with autoimmune hypothyroidism). Moreover, when Graves' patients were divided according to HLA-DR3 status, there was a significantly reduced frequency of the 1.4-kb V α fragment in HLA-DR3-negative patients ( p < 0.05 compared to controls). There was no significant association of either thyroid disorder with polymorphisms of the T-cell receptor α- or ß-chain-constant region genes, after Taq I and Bgl II digestion, respectively. These results show that inherited variation in T-cell receptor genes, recognizable before any somatic event has taken place, may play a role in susceptibility to autoimmune disease.