Evaluation of flow cytometric expressions of CD96 and CD123 on leukemic stem cells in patients with adult acute myeloid leukemia and their utility as prognostic markers

Abstract

Background Acute myeloid leukemia (AML) is a disease associated with a risk of relapse or refractoriness to the frontline agents. This is attributable to the quiescent leukemic stem cells (LSC). We aimed to determine the expression status of CD96 and CD123 on the surface of LSC in adult patients with AML and their relationship to prognosis. Patients and methods A total of 40 adult patients with de novo AML and 40 age-matched and sex-matched controls were recruited from Center ‘X,’ City ‘Y,’ Country ‘Y’ from June 2017 to February 2018, with 1-year follow-up. Bone marrow samples were collected for flow cytometric analysis using CD34, CD38, CD96, and CD123 monoclonal antibodies. For cases, samples were obtained at diagnosis and on day 28 after chemotherapy, whereas for controls, samples were taken once. Results CD96 and CD123 expressions are significantly higher in patients with AML as compared with controls. CD96 expression is associated with higher initial bone marrow and peripheral blood blast percentages. Day28 CD96 expression is positively correlated with its expression on day 0 and with CD123 expression at diagnosis, with P values of less than 0.001 and 0.034, respectively. Both markers were much more frequently expressed on LSCs in differentiated AML as compared with ill-differentiated subtypes (P<0.05). Both markers are linked to poor therapy outcome, with inferior progression-free survival among CD96-positive and CD123-positive cases at day 28 (P=0.035 and 0.041, respectively). Conclusions CD96 and CD123 represent potential targetable markers for the future development of therapeutic armamentarium for AML.