Abatacept (CTLA4-Ig, Orencia®, Bristol Myers Squibb) and belatacept (LEA29Y, Nulojix®, Bristol Myers Squibb) are 90-kDa fusion proteins of the extracellular domain of human CTLA-4 and a modified Fc fragment of a human IgG1, used in the therapy against rheumatoid arthritis and transplant rejection, respectively, inhibiting CD80/CD86-mediated T cell activation. This evidence concerns the gene CTLA4 and rheumatoid arthritis.