CD4 and leukemia: In the current study, we performed extensive immunological examinations to further identify and functionally characterize CD8+ and CD4+ T-cell responses directed towards the NPM1-mutated protein in both PB and bone marrow (BM) samples collected from 31 adult NPM1-mutated AML patients at different time points, in order to correlate the dynamics of leukemia-specific immune responses with the clinical course of the disease.