Expression of CD123 in B-acute lymphoblastic leukaemia as a predictor of Bcr/Abl rearrangement and disease relapse

Introduction: CD123 is the alpha chain of the interleukin 3 receptor (IL-3R) and is generally expressed on hematopoietic progenitor cells, monocytes, B lymphocytes, and endothelial cells. Leukemic stem cells can be detected using CD123, and their usefulness for measuring residual disease and potential involvement in disease re- lapse is being evaluated. It also regulates the growth, proliferation, survival, and differentiation of hematopoietic cells, along with immunity and inflammatory re- sponse. Materials and Methods: Bone marrow or peripheral blood from 50 B-Acute Lymphoblastic Leukemia (B-ALL) patients were enrolled in the study. CD123 ex- pression was studied by the flow cytometry technique and correlated with clinical and hematological parameters, as well as BCR-ABL status, MRD status, and disease status. Results: CD123 expression was found positive in 38% of patients. No significant cor- relation of CD123 expression with clinical and hematological parameters was ob- served. A significantly higher incidence of CD123 expression was noted in patients with BCR-ABL fusion (70%), relapse patients (67%), and MRD patients (67%). Conclusion: CD123 can be used to predict BCR-ABL status in B-ALL patients, and it has a potential role in recognizing high-risk relapse and helps to scrutinize high-risk B-ALL patients who benefited from aggressive chemotherapy. Further, higher ex- pression of CD123 in MRD patients can be used to evaluate minimal residual disease in follow-up B-ALL patients.