After treatment, the levels of serum IgG (12.00±5.46 g/L, P<0.001) and CD19+ cell percentage (11.01±7.85%, P<0.05) were much lower than that before treatment (19.54±4.28 g/L, 12.47±2.19%, respectively) in non-respond ITP group and did not differ significantly from the controls. Here, CD19 is linked to autoimmune thrombocytopenic purpura.