CTLA-4 and its role in autoimmune thyroid disease.

Autoimmune thyroid disease (AITD) occurs in two common forms: Graves' disease and Hashimoto thyroiditis. On the basis of functional and experimental data, it has been suggested that the gene encoding cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is a candidate gene for conferring susceptibility to thyroid autoimmunity. In this review, we critically evaluate the evidence for pathogenetic involvement of CTLA-4 in the various forms of AITD and focus on the possible role of genetic variation of the CTLA4 locus. Population genetics data strongly suggest a role for the CTLA4 region in susceptibility to AITD. However, further functional studies are required to understand the significance of CTLA4 polymorphisms in the pathogenic mechanism of AITD.