The transcriptomic analysis of BM–infiltrating CD4⁺ T cells in AML indicates T-cell activation and Th1 polarization. (A) PCA based on the transcriptomic profile of BM–infiltrating CD4⁺ T cells from patients with AML (n = 30) and controls (n = 7). (B) Heat map illustrating differentially expressed genes in CD4⁺ T cells (AML vs Ctrl). (C) Balloon plots illustrating significantly upregulated/downregulated pathways (left panel) or crucial immune-related signaling (right panel) within CD4⁺ and CD8⁺ T cells based on GSEA and normalized enrichment scores (NES). (D) Heat map illustrating the expression profile of key genes and transcription factors regulating CD4⁺ T-cell polarization (Th1, Th2, Th9, Th17, Th22, and Tregs). (E) Gene expression analysis of IFNG, TNF, and TBX21 in BM–infiltrating CD4⁺ T cell from patients with AML (n = 20) and HDs (n = 9) assessed by scRNA-seq. (F) Frequency of Th1 CD4⁺ T cells (IFNG, TNF, or TBX21 expressing CD4⁺ T cells) and Tregs (FOXP3 expressing CD4⁺ T cells) from patients with AML (n = 20) and HDs (n = 6) analyzed by scRNA-seq. (E-F) Two-sided Wilcoxon test. CTRL, control; PCA, principal component analysis; pos., positive.