HLA-DRB5 and autoimmune thrombocytopenic purpura: As illustrated in Figure 3a, positive expressions of MHC-II, CD80 and CD86 were increased in PBMCs of ITP mice (Figure 3b–d, p < 0.05), which were reversed in PBMCs of ITP mice with HLA-DRB5 deficiency (Figure 3b–d, p < 0.05).