IMMUNOPHENOTYPING IN THE DIAGNOSIS AND CLASSIFICATION OF ACUTE LEUKEMIA: NATIONAL ONCOLOGY CENTER, ADEN

Mayson Awadh Akrabi and Gamal Abdul Hamid*

ABSTRACT

Background: Acute leukemia comprises a heterogenous group of malignancies with variable clinical, morphologic, immunophenotypic and, molecular features. Flow cytometry is a crucial tool in the diagnosed and subtype hematological malignancy, especially acute leukemia, determining prognosis and monitoring response to therapy. By detecting various antigens presenting in various parts of cell, it is possible to know cell lineage and immaturity of the cell or group of cells. Objective: To evaluate immunophenotypic patterns of acute leukemia patient by multiparameter flowcytometry that help in the diagnosis and proper classification of acute leukemias. Materials and Methods: A descriptive study of acute leukemia cases was conducted at National Oncology Center Aden in Al -Sadaka Teaching Hospital over one year (January 2015 to June 2016). A total of 55 cases of acute leukemia diagnosed by multi parameter flow cytometry performed on peripheral blood and/ or fresh bone marrow aspirates. Results: 55 cases of acute leukemias were retrieved; 29(52.7%) of them were acute lymphoblastic leukemia (ALL), were B cell type (n=27) more than T cell type (n=2), and the remainder 26(47.3%), were proved by flowcytometry to be acute myeloblastic leukemia subtypes and one was acute myeloblastic leukemia (AML) with mixed phenotype (biphenotypic). Progenitors markers (CD34, HLA-DR, CD117 and TdT) were expressed more in acute myeloblastic leukemia more than in acute lymphoblastic leukemia blast cells, except TdT which was expressed by 13.8% of acute lymphoblastic leukemia (ALL) patients but not in acute myeloblastic leukemia patients. The B-lineage markers that expressed with higher percentage among ALL patients included CD19, CD10 and CD79a. Followed by CD20 and CD22. Only 2 patients with ALL expressed CD7 and cytoplasmic CD3 at the same times. Among the T-lineage markers, CD7 was aberrantly expressed in 26.9% and CD19 among B-lineage markers expressed 30.8% of AML patients. Conclusion: In our study the markers that expressed with higher percentage among ALL patients included CD19, CD10 and CD79a. The myeloid markers that were expressed markedly in AML patients included CD13, CD33 and cytoplasmic MPO.

Keywords: Acute leukemia; Immunophenotyping flowcytometry.