Immunophenotypic aberrancies in acute lymphoblastic leukemia from 282 Iraqi patients

Abstract

Introduction: The identification of aberrancies in leukemia-associated immunophenotype (LAIP) of acute lymphoblastic leukemia (ALL) is quite important in the assessment of minimal residual disease (MRD). This study, the first from Iraq, aimed to assess the frequency and patterns of LAIP among Iraqi patients with ALL, to establish future strategies for evaluating MRD.

Methods: A total of 282 newly diagnosed Iraqi ALL cases were analyzed with six-parameter flow cytometry using a panel of 29 monoclonal antibodies.

Results: Immunological subtyping revealed that 85.5% of cases were B-ALL and the remainder T-ALL. LAIP was detected in 97.1% of B-ALL, and in 26.8% of T-ALL. The asynchronous maturation-associated antigen patterns in B-ALL were CD10^strong+ /TdT^dim+ , CD38^dim+ /CD34⁺ , CD10^dim+ /CD34⁺ , CD10^strong /CD20^strong+ , CD20^strong+ /CD34^+, and CD45^dim+ /CD20^strong+ in 84.6%, while the cross-lineage myeloid expression was seen in 81.3% and aberrant T-cell antigen expression in 6.2%. For T-ALL, asynchronous maturation-associated antigen patterns included the following: CD1a⁺ /CD5⁺ /sCD3⁺ and CD34⁺ /sCD3⁺ in 12.2%. Myeloid and B-cell antigen expression were each identified in 7.3% of T-ALL. No significant differences in LAIP were found between children and adults.

Conclusion: The high rates and the patterns of LAIP particularly in Iraqi B-ALL patients may allow the development of more cost-effective strategies for MRD monitoring.

Keywords: acute leukemia; acute lymphoblastic leukemia; flow cytometry; immunophenotyping; minimal residual disease.