Bone Marrow Lymphocyte Subsets in Newly Diagnosed Acute Myeloid Leukemia Patients and Their Relation to Standard Prognostic Factors and Response to Induction Therapy

Aims: Immune responses act as a surveillance and protective system against malignant cells. Thus, the aim of this work was to study different lymphocyte subsets in bone marrow (BM)of newly diagnosed acute myeloid leukemia (AML) patients and identify their prognostic significance.

Study Design: Cohort study.

Place and Duration of Study: Hematology department of Ain-Shams University Hospital (ASUH) from July 2017 till March 2018.

Methodology: This study was conducted on 33 newly diagnosed AML patients, all were subjected to peripheral blood count and flow cytometric immunophenotyping on bone marrow (BM) blasts (using acute leukemia panel in addition to monoclonal antibodies to detect different BM lymphocyte subsets); whereas cytogenetic studies using fluorescence in situ hybridization (FISH) technique were performed to determine risk groups. The patients’ remission status following induction therapy (day28) was determined.

Results: Natural killer (NK) cells were relatively elevated (median 15.9%) in t (15:17), while the median percentage of T- cytotoxic (Tc) [43.5%], T-helper (Th) [39.5%] and NK-T cells [39.9%] were higher in t (8:21). Percentage of BM total lymphocytes showed a significant negative correlation with both total leukocyte count (r=-0.645, p<0.001) and percentage of BM blasts (r=-0.348, p=0.047), with positive correlation with platelet count (r=0.42, p=0.015). A numeric cutoff of 5% and 48% for both total BM lymphocytes and T-cytotoxic cells, respectively were associated with good response to induction.

Conclusion: Total BM lymphocytes and their subsets in BM of newly diagnosed AML patients were different from normal values. High total BM lymphocytes, T-helper, cytotoxic and B-cells were associated with complete remission to induction therapy.