CCR4 and autoimmune thrombocytopenic purpura: CCR4 levels on BM and PB CD4+IL-22+ T cells from ITP patients were remarkably elevated compared with HCs (BM: 2584.3 ± 824.5 vs. 1624.8 ± 217.4, P = 0.005; PB: 2402.8 ± 607.3 vs. 1496.2 ± 155.4, P = 0.008).