Decreased expression of BCL2 protein on the diagnostic bone marrow T cells in adult acute myeloid leukemia

B-cell lymphoma-2 (BCL2) is an anti-apoptotic molecule. Previous studies on its function focused on leukemic cells in acute myeloid leukemia (AML), whereas its effect in lymphocytes is unclear. We performed multi-parameter flow cytometry to test BCL2, immune checkpoint and cytotoxic molecules on T and NK cells in bone marrow samples of 80 newly diagnosed adult AML patients and 7 healthy donors (HDs). BCL2 expression was evaluated on T-cell differentiation subsets in a subset of 28 AML patients and 6 additional HDs. AML patients had lower BCL2⁺ frequencies on CD4⁺T and CD8⁺T cells and similar frequency on NK cells than HDs (p = 0.001, 0.001 and 0.34). Effector memory T cells had lower BCL2⁺ frequency than naïve T, stem central memory T and central memory T cells (all p < 0.05) in AML. Lower BCL2⁺ frequency on NK cells predicted higher 1-course complete remission rates (p = 0.016). Lower BCL2⁺ frequency on T cells was related to poor relapse-free survival (all p < 0.001) and that on CD4⁺T cells was an independent predictor (p = 0.008). BCL2⁺ cells had lower PD1⁺ and TIM-3⁺ frequencies than BCL2^- cells on CD4⁺T cells, and lower PD1⁺ but higher TIM-3⁺, perforin⁺ and Granzyme B⁺ frequencies compared to BCL2^- cells on CD8⁺T and NK cells (all p < 0.05). BCL2 expression on T and NK cells in diagnostic bone marrows are associated with treatment response and outcome in adult AML, which might be relevant to their association with immune checkpoint and cytotoxic molecules expression.