New therapies are highly needed to stabilize remission in patients with acute myeloid leukemia (AML). This study investigates the value of dendritic cells derived from leukemic blasts (DC_leu) to enhance anti-leukemic immunity after T-cell-enriched mixed lymphocyte cultures (MLCs). We correlated induced anti-leukemic activity with patient data, including biological, clinical and prognostic factors. Additionally, we correlated the frequencies of DC/DC_leu and leukemic-specific T cells with the achieved anti-leukemic activity after MLC. We show that mature DC/DC_leu can be generated using the immunomodulating Kit-M, which contains granulocyte–macrophage colony-stimulating-factor (GM-CSF) and prostaglandin E₁ (PGE₁), without inducing blast proliferation from leukemic whole blood (WB) samples. Activated leukemia-specific immune and memory cells increased after MLC with Kit-M-pretreated WB, leading to improved blast lysis. Enhanced anti-leukemic activity positively correlated with the frequencies of generated DC/DC_leu, proliferating leukemic-specific T cells and memory T cells, but not with leukemic blast counts, hemoglobin levels or platelet counts at diagnosis. No correlation was found between improved blast lysis and patients’ prognostic data, including age, gender, ELN risk groups, disease stage and response to induction chemotherapy. These findings underscore the potential of DC/DC_leu to evoke robust immune responses and potential immunological memory against AML. Overall, this innovative approach could pave the way for the development of improved immunotherapeutic strategies that function in vivo.

Various AML treatment regimens might trigger different immunological mechanisms against leukemic cells. The role of different immune cell subsets in the mediation of antileukemic processes is not clear. In this study, we longitudinally assessed (leukemia specific) immune subtype compositions in 17 AML patients before stem cell transplantation (SCT) at different timepoints in the course and in different stages of the disease using flow cytometry. Further we correlated immune cell compositions with patients’ response to induction therapy and the median survival (3.8 months in our cohort) of the patients. Finally, we compared immune cell profiles from patients before and after SCT. (1) Patients in CR (compared to dgn and PD) were characterized by higher frequencies of leukemia-derived DC (DCleu), (leukemia-specific—IFNg or TNFα producing or CD107a degranulating) anti-tumor relevant T cells (Tgd, Tβ7), central/effector memory cells (Tcm, Tem), alongside with lower frequencies of (leukemia-specific) regulatory T cells. (2) Patients with higher frequencies of (leukemia-specific) antitumor relevant T cells, (leukemia-specific) memory T cells and NK cells demonstrated a prolonged median survival time and/or responded better to induction (RTI) treatment (3) Comparing patients before and after SCT, only minimal differences were observed. However, patients in CR_preSCT exhibited higher frequencies of DC, Tcm, Tβ7 and leukemia-specific iNKT cells compared to patients in CR_postSCT. (1) Immune monitoring qualifies to quantify (leukemia-specific) immune cells in different stages and under different treatment strategies in the course of AML. (2) Higher frequencies of activating and antitumor relevant leukemia-specific immune cell subtypes found after ‘costimulatory’ (especially KitM induced) treatment’ and in CR. (3) In particular, DC/DCleu, (leukemia-specific) antitumor-relevant T (memory) and NK cells seem to dominate in CR and positively influence RTI and survival. (4) Monitoring of (leukemia-specific) immune cell subtypes contribute to quantify individual AML patients’ antileukemic potential in different stages and treatment groups and also could be used to predict patients’ survival.