Immunophenotypic Diagnosis of Acute Lymphoblastic Leukemia Using Flow Cytometry : Experience at King Hussein Medical Center

Abstract

Objective: To identify the importance of flow cytometry (FCM) in diagnosis and subclassifying acute lymphoblastic leukemia, and to highlight its capability to detect antigen aberration. Method: The Results of flow cytometry for 165 patients, between January 2006 and December 2011 who were diagnosed with acute lymphoblastic leukemia (ALL) were retrospectively reviewed with respect to age and gender distribution and immunophenotypic findings. Results: 63% of patients were children (104 out of 165 patients) with age less than fourteen years old. 114 patients were male while 51 patients were female with male to female ratio 2.2: 1. PrecursorB- acute lymphoblastic leukemia represents eighty percent (132 patients) of cases, of 106 patients (87.6%) were [CD10/CD19] positive,125 patients (94.7%) were positive for cytoplasmic CD79a, 126/129 (97.6%) were positive for HLA-DR, and 15 patients (11.36%) were CD10 negative. Aberrant myeloid antigen expression was noted; CD33 and CD13 were positive in 15/113 (13.3%) and 2/108 (1.85%) respectively. On the other hand precursor-T- acute lymphoblastic leukemias were found in thirty three patients, 84.4% of them were Anti-TdT positive, and all were negative for B-cell markers. Myeloid antigen expression results were as follows; 1/29 (3.4%) and 2/29 (6.9%) positive for CD33 and CD13 respectively Conclusion: Flow cytometry is a golden tool in diagnosis and identifying ALL subtypes. PrecursorB- acute lymphoblastic leukemia represents most of ALL cases with minority of cases are CD10negative. Aberrant myeloid antigen expression would not change the diagnosis of ALL in either B- or T- subtypes. Further clinical correlation is needed to figure out aberrant markers prognostic implications.