CML Shows Characteristic Pattern by Flow Cytometry Analysis of Peripheral Blood

Abstract 4430

A total of 75 chronic myeloid leukemia (CML) cases from peripheral blood (40 cases) and bone marrow (BM, 35 cases) with adequate flow cytometry (FC) data, smear, blood cell count, and the presence of t(9;22)/BCR-ABL by fluorescence in-situ hybridization (FISH) studies were analyzed for immunophenotypic pattern. The FC pattern in CML was compared with benign (healthy) controls (blood, 20 cases; BM, 20 cases), blood with reactive neutrophilia (15 cases), myelodysplastic syndrome (BM, 15 cases), and blood with eosinophilia (15 cases). CML showed a characteristic pattern by FC in blood, which can be easily differentiated from reactive neutrophilia or eosinophilia, regardless of WBC count. The identification of distinct population of blasts, basophilia, lack of CD10, CD11b, CD13 and/or CD16 on subset of granulocytes, decreased granularity, and/or aberrant expression of CD56 on granulocytes and monocytes, can be easily identified by routine FC analysis. We suggest using FC analysis of blood as a screening tool for patients with leukocytosis (neutrophilia) with follow-up FISH studies in cases with the phenotypic features suggestive of CML. Patients with confirmed CML diagnosis by FISH will undergo marrow biopsy for differential count including blast and basophil enumeration (to exclude accelerated phase or blast crisis), degree of reticulin fibrosis and cytogenetic studies (for additional chromosomal changes present at diagnosis). This approach, in our opinion, allows to diagnose early (unsuspected) CML and eliminates the need for unnecessary cytogenetic/FISH testing, and especially bone marrow biopsy in patients with reactive leukocytosis or eosinophilia.