CTLA4 gene polymorphism and autoimmunity

CD28 and cytotoxic T‐lymphocyte antigen‐4 (CTLA4) are two receptors that have critical but opposing functions in T‐cell stimulation. CD28 promotes a number of T‐cell activities, whereas in contrast CTLA4 is an essential inhibitor of T‐cell responses. Because of its inhibitory role, CTLA4 is a strong candidate susceptibility gene in autoimmunity and several studies suggest disease‐associated polymorphisms. In this review, we discuss recent progress in relating CTLA4 polymorphisms to disease susceptibility and consider the putative mechanisms by which CTLA4 may act to inhibit autoimmunity.