PDCD1 and acute myeloid leukemia: T cells are a major arm of the anticancer immune response post-allograft, yet controversy remains over their functional state in AML.26,27 In a smaller cohort, T-cell exhaustion in patients with AML may predict relapse post–allo-SCT.28 Correspondingly, we have shown that the T cells in patients post-transplantation have an exhaustion phenotype manifested by increased PD1 and LAG3 expression, in combination with reduced interferon-γ, tumor necrosis factor–α, IL-2, IL-5, and IL-6 secretion.