CTLA4 and autoimmune disease: In this review, we focused on the immunomodulatory role of CTLA-4 in T-cell immunity, discussed the key molecular signaling pathways mediated by CTLA-4, and summarized the latest immunoregulatory effects of CTLA-4 in various autoimmune diseases, especially its role in the progress and pathogenesis of the diseases and its clinical application in the diseases.