IRF4 and autoimmune thrombocytopenic purpura: Although not all but 5 samples for each group were examined due to the sparse of the blood specimens, the expression level of IRF4mRNA and IRF4 protein of Treg cells in ITP patients did show to be lower than that of healthy volunteers, indicating that the immunosuppressive function of IRF4-deficient Treg cells was impaired in ITP setting.