Association of MICA Alleles with Autoimmune Thyroid Disease in Korean Children

Abstract

Background. Major histocompatibility complex class I chain-related gene A (MICA) is a ligand for the activating NKG2D receptor expressed on natural killer (NK) cells. We aimed to assess the association of MICA polymorphism with autoimmune thyroid disease (AITD) in Korean children.Methods. Eighty-one patients with AITD were recruited. We analyzed MICA polymorphisms by PCR-SSP and compared the results with those of 70 healthy controls.Results. In AITD, the allele frequencies of MICA*010 (OR=2.21; 95% CI, 1.30–3.76,P<0.003,Pc<0.042) were higher than those of controls. Patients who did not have thyroid-associated ophthalmopathy showed higher frequencies of MICA*010 (OR=2.99; 95% CI, 1.47–6.08,P<0.003,Pc<0.042) and lower frequencies of MICA*008 (OR=0.08; 95% CI, 0.01–0.62,P<0.001,Pc<0.014) compared to those of controls. HLA-B*46, which shows the strongest association with AITD compared with other HLA alleles, showed the strongest linkage disequilibrium with MICA*010. Analyses of the associations between MICA*010 and HLA-B*46 with AITD suggest an association of the MICA allele with AITD.Conclusions. Our results suggest that innate immunity might contribute to the pathogenesis of AITD.