Comprehensive immunoprofile of NK cells from CML patients in TFR reveals a possible role of memory-like NK cells

M. BIANCHINI; SANCHEZ MB

virtual

Congreso; European Hematology Association; 2021

Long-term survival of patients with chronic myeloid leukemia (CML) has significantly improved since the introduction of BCR-ABL1 tyrosine kinase inhibitors (TKIs). Several clinical trials show that approximately half of patients who achieve a sustained deep molecular response during TKI treatment maintain molecular remission after stopping TKIs. There is currently no biomarker that reliably predicts treatment free remission (TFR) in CML, but growing evidence remarks the importance of the immune system, especially of Natural Killer (NK) cells in this scenario. Our aim is to discover a biomarker for TFR prediction by analyzing the conventional and adaptive phenotype of NK cells at the time of discontinuation and their relation to successful TKI cessation, and to assess any phenotypic changes throughout the months without treatment.Fifty chronic phase CML patients who participated in the Argentina Stop Trial were recruited from 7 Argentinian centers. Peripheral blood samples were collected before TKI stopping and then at months 3, 12 and at any time when MR3.0 was lost. Freshly isolated mononuclear cells were immunophenotyped by staining with CD3, CD16, CD25, CD56, CD57, CD158, NKp30, NKp44, NKp46, NKG2A, NKG2C, NKG2D and PD-1 antibodies and subpopulations of NK cells were analyzed by flow cytometry (BD FACS Canto™II). Molecular recurrence-free survival was estimated by the Kaplan–Meier method. Mann Whitney test, Wilcoxon test or paired T test were performed to compare variables between groups, where p