An Analysis of Immunophenotyping Characteristics in Fifty Adult Cases with Acute Lymphoblastic Leukemia

Objective To investigate the immunophenotypic characteristics in adult acute lymphoblastic leukemia (ALL), and its association with the cytomorphology and cytogenetics. Methods Immunophenotyping was performed in 50 adult patients with ALL by flow cytometry analysis using a panel of monoclonal antibodies and CD45/SSC gating. Results Among the 50 cases of ALL,42 were B lineage-ALL, 5 were T lineage-ALL and 5 were hybrid B-T phenotype. Myeloid antigen expression was identified in 27 of the cases, and the expressed myeloid antigens were mainly CD13 and CD33. Almost all of the cases were absent of CD45 antigen or with dim fluorescence intensity on blast cells in ALL.The majority of the cases was FAB L1 ALL.27% were L2 subtype. Three cases of L3 subtype had a pre-B and a mature B-cell immunophenotype. Twenty cases had cytogenetic abnormalities, and 6 with sole numerical aberrations including +8,-X,-7,-11,-4,-6 and -13. The most frequent structure abnormality was t (9;22) which all expressed myeloid-associated antigens. Conclusion Immunophenotypic data should not be used as a sole diagnostic criterion, and should be considered together with morphologic and cytogenetic characteristics.