Study of the A／G49 polymorphism of CTLA-4 gene exon 1 in autoimmune thyroid diseases / 免疫学杂志

ABSTRACT

Objective　To investigate the association of gene polymorphism of cytotoxic T lymphocyte-associated antigen 4（CTLA-4） with autoimmune thyroid diseases. Methods　The A／G transition polymorphism at position 49（exon 1，codon 17） of the CTLA-4 gene was determined by polymerase chain reaction restriction fragment length polymorphism （PCR-RFLP）method in 122 autoimmune thyroid diseases patients which included 87 Graves’ disease （GD） patients and 35 Hashimoto's thyroiditis（HT） patients， as well as 84 control subjects. We detected their thyroid function by ELISA technique， and the thyroid autoimmune antibodies （TGAb，TPOAb） by indirect immunofluorescent technique. Results　The strong association of the CTLA-4／G49 allele with AITDs was seen in our study（66.4％ vs 36.9％ P＜0.0001）. The G allele in GD patients was significantly increased compared with control subjects（69.5％ vs 36.9％， P＜0.0001）. In HT patients， the frequency of G allele was also higher than control subjects（58.6％ vs 36.9％，P＜0.01）， and there was no significant difference between HT and GD groups. When GD and HT subjects were stratified with respect to sex， neither female nor male patients demonstrated evident association of G49 allele with gender.Conclusions　The polymorphism of CTLA-4 gene （exon 1 condon 17 position 49）confers susceptibility to AITDs. This association is independent of sex.