Evaluation of CD96 and CD123 in CD34+ leukemic stem cells in acute myeloid leukemia patients and their relation to response to induction therapy

Background: Leukemic stem cells (LSCs) are thought to originate either from normal hematopoietic stem cells or from more differentiated progenitor cells. LSCs are capable of self-renewal, proliferation, and differentiation into malignant blasts. Objective: To evaluate the expression of the LSC markers CD96 and CD123 in de novo acute myeloid leukemia (AML) patients, and to explore the relationship between those markers and response to induction therapy and prognostic factors in AML. Materials and Methods: A cross-sectional study was conducted on 30 adults with newly diagnosed AML patients were prospectively tested for the expression of CD96 and CD123 using four-color flow cytometer at the time of diagnosis and re-evaluated at day 28 from the start of chemotherapy for the response to 3 + 7 induction therapy regimen. Results: Eight cases (26.7%) expressed CD96, and 12 cases (40%) expressed CD123; all the CD96 positive cases were also CD123 positive, however, four cases among the CD123 positive patients did not express CD96. CD96 and CD123 were expressed more on blast cells in the cases of M5 French-American-British subtype, whereas the least expression was in M3. Among the eight cases with CD96+ expression, only (37.5%) acquired CR, whereas cases without CD96 expression, (77.3%) acquired CR. Among the 12 cases with CD123+ expression, only (33.3%) acquired CR, while cases without CD123 expression, (88.9%) acquired CR. Conclusion: The expressions of CD96 and CD123 were associated with a higher total white blood cell count and bone marrow blast cells at presentation, and a lower response rate to the induction therapy.