Avaliação da contagem de células Natural Killer (NK) como fator predisponente de mucosite e de impacto no desfecho clínico durante a quimioterapia de indução em pacientes com leucemia aguda

Abstract

Acute leukemia is a malignant disease characterized by the clonal proliferation of immature hematopoietic cells in the bone marrow. Gastrointestinal mucositis is an inflammatory process characterized by erythema and ulceration that can occur in any region of the digestive mucosa and is an important and costly side effect associated with induction chemotherapy used for leukemia. NK cells are a subtype of lymphocytes that play an important role in innate immunity through several mechanisms. Objectives: Evaluate the correlation between NK cell count and the development of oral mucositis and diarrhea in patients with acute leukemia undergoing induction chemotherapy. Materials and methods: The study followed a prospective, observational and analytical model, with patients with acute leukemia as the target population. The sample consisted of 70 patients diagnosed between August 2023 and December 2024. For data collection, the percentage of NK cells determined by flow cytometry of material from bone marrow or peripheral blood, electronic medical records, and a data collection form prepared by the authors were used. Results: The mean age of patients was 43 years, with a range from 21 to 68 years. The most common leukemia phenotype in our study was acute myeloid leukemia, which corresponded to 47 patients (67.1%); regarding cytogenetic/molecular risk, most patients (63.2%) were classified as high risk. Regarding gastrointestinal adverse effects, 36 patients (59%) had some degree of oral mucositis and 31 patients (50.8%) had some degree of diarrhea. Regarding infection, 53 patients (86.9%) had febrile neutropenia and 46 patients (75.4%) had some degree of infection with a defined focus. When the samples of 27 patients who underwent NK cell percentage testing before and after induction chemotherapy were evaluated, most patients (77.7%) showed a decrease in NK cell levels after treatment, and a significant association was observed with the presence of oral mucositis and diarrhea, number of T lymphocytes, monocytes and clinical outcome when the decrease in NK cell levels after induction chemotherapy was greater than 6%. Conclusion: The reduction in the blood percentage of NK cells after treatment was associated with oral mucositis, diarrhea, infection and with a better response rate during induction chemotherapy in patients with acute leukemia, which highlights the potential relevance of NK cells as a possible prognostic and therapeutic biomarker in this clinical context.