TGFBR2 and autoimmune thrombocytopenic purpura: Comparing to younger patients, elderly primary ITP patients demonstrated elevated prevalence of TGFBR2 variants (13.6% vs. 2.1%, p = 0.037), slightly decreased CD19+ B cell population [(16 ± 10)% vs. (21 ± 6)%, p = 0.053], and further elevated co-expression of IL-17 [(16.9 ± 13.8)% vs. (5.2 ± 3.0)%, p = 0.017] in Tregs (Table 2).