CD38 expression and tumor immune composition in older patients with AML. (A) Distribution of 241 older patients with newly diagnosed AML according to the pattern of CD38 expression: negative, heterogeneous, and homogeneous positive. (B) OS of the 241 older patients with AML treated in the PETHEMA/FLUGAZA phase 3 clinical trial, stratified according to the percentage of CD38⁺ tumor cells at diagnosis: <50% (green), 50% to 99% (blue) and 100% (red). (C-D) CD38 expression in patient-matched tumor cells at diagnosis, complete response after 3 induction cycles in patients with measurable residual disease (MRD, n = 10), and at relapse (n = 3). (E) Mean fluorescence intensity (MFI) of CD38 in tumor cells from the 241 patients with AML and in BM plasma cells from 10 healthy adults. (F) t-Distributed Stochastic Neighbor Embedding (t-SNE) projection nucleated cells in the BM of older patients with AML and healthy adults (n = 10). (G-H) Frequency of BM NK and T lymphocytes among total alive nucleated cells in BM from patients with AML vs healthy adults. All panels, ∗P < .05; ns, non-significant.