Abatacept is a T-cell costimulation modulator consisting of an extracellular domain of human cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and a modified Fc portion of human IgG1.271 According to Hayakawa et al., plasma miR-766-3p levels were lower in abatacept-treated RA patients than in untreated patients. This evidence concerns the gene CTLA4 and rheumatoid arthritis.