CD8A and autoimmune thrombocytopenic purpura: Many of the features of T-lymphocyte dysregulation have been described in ITP, such as the shift in T–helper 1/T-helper 2 (Th1/Th2) balance,4 increased Th17,5 and decreased numbers of CD4+ CD25+ T-regulatory cells, which function to downregulate the T-cell responses.6 Moreover, cytotoxic T lymphocyte (CD8+) can mediate platelet destruction,7,8 as platelet-specific CD8+ have been found to be elevated in patients with active ITP.9 Additionally, the ratio between T-helper lymphocyte (CD4+) and CD8+ (CD4:CD8) is diminished in ITP and improves with disease remission.10