Expression of CD123 in B-Acute Lymphoblastic Leukemia 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 normally expressed on hematopoietic progenitor cells, monocytes, B lymphocytes and endothelial cells. Leukemic stem cells can be detected using CD123, and its usefulness for measuring residual disease and potential involvement in disease relapse is being evaluated. It also regulates the growth, proliferation, survival, and differentiation of hematopoietic cells, along with immunity and inflammatory response.

Materials and Methods: Bone marrow or peripheral blood from 50 B-Acute Lymphoblastic Leukemia (B-ALL) patients were enrolled in the study. CD123 expression was studied by 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 correlation of CD123 expression with clinical and hematological parameters was observed. 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 potential role to recognize high risk of relapse and helps to scrutinize high risk B-ALL patients who benefited with aggressive chemotherapy. Further, higher expression of CD123 in MRD patients can be used to evaluate minimal residual disease in follow-up B-ALL patients.