CTLA4 and rheumatoid arthritis: Although we did not find a correlation regarding CTLA-4 + 49 A/G (rs231775) between patients with ITP and HCs, a large metanalysis by Wang et al., who searched the same SNP in different autoimmune diseases like RA and type 1 DM including a considerable number of patients (N, 4732), found that CTLA-4 + 49 G/A (rs231775) is associated with the susceptibility of autoimmune disease in Asian and Caucasian populations [26].