Prognostic significance of the frequencies of bone marrow lymphocyte subsets in adult acute myeloid leukemia at diagnosis

Abstract

Introduction: Immune microenvironment plays an important role in the occurrence and development of acute myeloid leukemia (AML). Studies assessing the prognostic significance of bone marrow (BM) lymphocyte subsets' frequencies at diagnosis in patients with AML were limited.

Methods: Fresh BM samples collected from 97 adult AML patients at diagnosis were tested for lymphocyte, T, CD4⁺ T, CD8⁺ T, γδT, NK, and B cell frequencies using multi-parameter flow cytometry.

Results: Low frequencies of lymphocytes, T, CD4⁺ T, and CD8⁺ T cells were associated with significantly lower rates of one-course complete remission (CR) (all p < 0.05). Moreover, the frequency of CD4⁺ T cells independently predicted one-course CR achievement (p = 0.021). Low frequencies of T and CD8⁺ T cells were significantly associated with lower relapse-free survival (RFS) rates (p = 0.032; 0.034), respectively, and a low frequency of CD8⁺ T cells was associated with a significantly lower overall survival (OS) rate (p = 0.028). Combination of frequency of CD8⁺ T cells and ELN risk stratification showed that patients with ELN-intermediate/adverse risk + high CD8⁺ T cell frequency had a similar RFS rate to those with ELN-favorable risk + high CD8⁺ T cell frequency and those with ELN-favorable risk + low CD8⁺ T cell frequency (p = 0.88; 0.76), respectively. The RFS rate of patients with ELN intermediate/adverse risk + low CD8⁺ T cell frequency was significantly lower than that of all aforementioned patients (p = 0.021; 0.0007; 0.028), respectively.

Conclusion: The frequencies of BM lymphocyte subsets at diagnosis predicted clinical outcomes and could help improve risk stratification in AML.

Keywords: AML; at diagnosis; bone marrow; lymphocyte subsets; prognostic significance.