1. Specific T-cell immune responses against colony-forming cells including leukemic progenitor cells of AML patients were increased by immune checkpoint inhibition
- Author
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Susanne Hofmann, Lars Bullinger, Jochen Greiner, M Wiesneth, Marlies Götz, Hartmut Döhner, Vanessa Schneider, and Hubert Schrezenmeier
- Subjects
Cancer Research ,Myeloid ,T-Lymphocytes ,T cell ,Programmed Cell Death 1 Receptor ,Immunology ,Ipilimumab ,B7-H1 Antigen ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Humans ,Immunology and Allergy ,CTLA-4 Antigen ,Progenitor cell ,business.industry ,Minimal residual disease ,Immune checkpoint ,Nivolumab ,Treatment Outcome ,medicine.anatomical_structure ,Oncology ,Leukemia, Myeloid ,Acute Disease ,Neoplastic Stem Cells ,Cancer research ,Immunotherapy ,business ,T-Lymphocytes, Cytotoxic ,030215 immunology ,medicine.drug - Abstract
The efficacy of immunotherapies in cancer treatment becomes more and more apparent not only in different solid tumors but also in hematological malignancies. However, in acute myeloid leukemia (AML), mechanisms to increase the efficacy of immunotherapeutic approaches have to be further elucidated. Targeting leukemic progenitor and stem cells (LPC/LSC) by specific CTL, for instance, in an adjuvant setting or in minimal residual disease, might be an option to prevent relapse of AML or to treat MRD. Therefore, we investigated the influence of immune checkpoint inhibitors on LAA-specific immune responses by CTL against leukemic myeloid blasts and colony-forming cells including leukemic progenitor cells (CFC/LPC). In functional immunoassays like CFU/CFI (colony-forming units/immunoassays) and ELISpot analysis, we detected specific LAA-directed immune responses against CFC/LPC that are postulated to be the source population of relapse of the disease. The addition of nivolumab (anti-PD-1) significantly increases LAA-directed immune responses against CFC/LPC, no effect is seen when ipilimumab (anti-CTLA-4) is added. The combination of ipilimumab and nivolumab does not improve the effect compared to nivolumab alone. The anti-PD1-directed immune response correlates to PD-L1 expression on progenitor cells. Our data suggest that immunotherapeutic approaches have the potential to target malignant CFC/LPC and anti-PD-1 antibodies could be an immunotherapeutic approach in AML. Moreover, combination with LAA-directed vaccination strategies might also open interesting application possibilities.
- Published
- 2020
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