The profile and prognostic significance of bone marrow T-cell differentiation subsets in adult AML at diagnosis.

Background: T lymphocytes in tumor microenvironment play a pivotal role in the anti-tumor immunity, and the memory of T cells contributes to the long-term protection against tumor antigens. Compared to solid tumors, studies focusing on the T-cell differentiation in the acute myeloid leukemia (AML) bone marrow (BM) microenvironment remain limited.

Patients And Methods: Fresh BM specimens collected from 103 adult AML patients at diagnosis and 12 healthy donors (HDs) were tested T-cell differentiation subsets by multi-parameter flow cytometry.

Results: CD4 and CD8 T-cell compartments had different constituted profiles of T-cell differentiated subsets, which was similar between AML patients and HDs. Compared to HDs, AML patients as a whole had a significantly higher proportion of CD8 effector T cells (Teff, = 0.048). Moreover, the T-cell compartment of AML patients with no mutations skewed toward terminal differentiation at the expense of memory T cells (CD4 Teff: = 0.034; CD8 Teff: = 0.030; CD8 memory T: = 0.017), whereas those with mutated had a decrease in CD8 naïve T (Tn) and CD4 effector memory T cells (Tem) as well as an increase in CD4 central memory T cells (Tcm) ( = 0.037, 0.053 and 0.053). Adverse ELN genetic risk correlated with a lower proportion of CD8 Tn. In addition, the low proportions of CD4 Tem and CD8 Tn independently predicted poorer relapse-free survival (RFS, HR [95%CI]: 5.7 (1.4-22.2), = 0.017 and 4.8 [1.3-17.4], = 0.013) and event-free survival (EFS, HR [95% CI]: 3.3 (1.1-9.5), = 0.029; 4.0 (1.4-11.5), = 0.010), respectively.

Conclusions: AML patients had abnormal profiles of BM T-cell differentiation subsets at diagnosis, which was related to mutations. The low proportions of CD4 Tem and CD8 Tn predicted poor outcomes.