At present, some recombinant fusion protein and monoclonal antibodies targeting costimulatory molecules, such as CTLA-4- and LFA-3-Ig, anti-CD3 monoclonal antibody, and so on have been developed and approved to treat autoimmune diseases, such as RA, SLE, IBD, MS, and psoriasis. This evidence concerns the gene CTLA4 and autoimmune disease.