Inhibitory receptors expression on T cells is associated with subsequent AML tumor relapse in the cross-sectional cohort. (A) PBMCs from 40 patients with AML, with (n = 20) or without (n = 20) documented subsequent tumor relapse, were collected at M3 after transplantation and analyzed by mass cytometry. (B) Unsupervised cell clustering of the T-cell compartment was performed with FlowSOM. (C) Volcano plots showing differences between patients with or without relapse in frequencies of FlowSOM-generated T-cell clusters. P-values by Mann-Whitney test. Clusters that were significantly different between both groups are annotated (percentage of cell clusters is among total CD3⁺ T cells or among CD8 or CD4 T cells, when indicated). (D) Frequencies of identified cell clusters among CD4 or CD8 T cells in relapsing (R) and nonrelapsing (NR) patients. (E) Heat map showing expression levels of indicated immunoregulatory molecules in relapse-associated cell clusters. (F) Expression of CD161, PD-1, TIGIT, and BTLA on total and relapse-associated CD4 T-cell clusters. (G) Expression of PD-1 and TIGIT on total and on the relapse-associated CD8 T-cell cluster. (H-I) Enrichment in the indicated IR positivity or expression density (median metal intensity, MMI) in relapse-associated clusters relative to total CD4 (H) and CD8 (I) T cells. (J) Frequencies of combined TIGIT clusters (C25+C26) or CD161 clusters (C22+C26) in relapsing (R) and nonrelapsing (NR) patients. Relapse-free survival (RFS) assessed using the Kaplan-Meier approach in patients with high (>median) vs low (<median) frequencies of indicated cell clusters are shown (right). P values by Mann-Whitney and log-rank tests, to compare cluster frequency and RFS, respectively. ****P < .0001.