In preliminary studies on patients with ITP, it was found that the concentration of IL-22 in the plasma was increased, which is closely connected with the count of Th1 and Th22 cells, but Th17 cells also secrete large amounts of IL-22, making it uncertain whether the increased level of IL-22 in ITP is mainly caused by Th1 and Th22 cells. This evidence concerns the gene IL22 and autoimmune thrombocytopenic purpura.