In ITP patients, positive correlations were found between the frequency of Th22 cells and IL-22 level both in BM and in PB (BM: r = 0.796, P < 0.001; PB: r = 0.737, P < 0.001, respectively; Figure 1M and N). This evidence concerns the gene IL22 and autoimmune thrombocytopenic purpura.