CD19 and autoimmune thrombocytopenic purpura: When stimulated with PMA and ionomycin for 24 hours, PBMCs from ITP patients showed higher percentage of IL-10+CD19+ B cells in total CD19+ B lymphocytes than that from normal controls ((10.65 ± 3.11)% and (6.85 ± 3.31)%, resp.; P < 0.001) (Figures 1(a) and 1(b)).