Flow Cytometry in Chronic Myelogenous Leukemia Blast Crisis

Background: Chronic myelogenous leukemia (CML) is a myeloproliferative disorder due to BCR-ABL1 translocation. Patients showing transformation into blast crisis (BC) have poorer treatment response and prognosis.  Methods: A retrospective study was conducted in the department of Pathology, Maulana Azad Medical College, New Delhi, India, over a time period of 5 years (2014-2019) to evaluate the immunophenotypic features of the blast population. Twenty-one Cases of CML in BC were subjected for multiparametric flow cytometry. Data of the subjects in CML blast crisis was compiled and analyzed for the immunophenotypic categorization of the blast population.  Results: The mean age of the patients at presentation was 39.84 years. Male to female ratio was 1:1.3. Out of 21 cases, 5 (23.8%) showed blasts of myeloid lineage, 8 (38%) myelomonocytic, 6 (28.5%) B lymphoid and 2 (9.5%) showed mixed lineage blast population.  Conclusion: Blast lineage in blast crisis of CML is heterogeneous and may show antigens of more than one lineage. Hence, it is necessary to evaluate the immunophenotypic nature of the blasts for the best appropriate management of the patients accordingly.