Prognostic effect of aberrant flowcytometric markers on outcome of children with acute lymphoblastic leukemia (Oncology Center - Mansoura University experience)

Abstract

Objective: While the available literatures provide conflicting evidence regarding both the prevalence and prognostic significance of aberrant antigen expression in children with B-acute lymphoblastic leukemia (B-ALL). This study aimed to determine its frequency and clinical impact, mainly on disease outcome.

Methods: We reviewed the records of children less than 18 years at diagnosis of B- ALL. The electronic data files were retrieved from Jan 2011 to December 2021. Only patients categorized as standard risk group were included in our study. The patients were followed for at least till the end of their treatment protocol. 

Results: Out of 159 cases, 53 (33.3%) exhibited expression of aberrant lineage antigens. Among all aberrantly expressed myeloid antigens, CD33 was the most common, present in 24 (15.1%) patients, followed by CD13 in 19 patients (11.9%). Relapse was significantly higher among the positive aberrant lineage group compared to the negative group (43.40% Vs 18.90%, respectively, p =0.001).  After multivariate adjustment, aberrant antigen lineage expression remained an independent determinant of reduced disease-free survival (DSF) (HR = 3.37). When evaluating individual antigen clusters, CD33 positivity was identified as a specific independent predictor, carrying a 2.28-fold higher hazard for reduced DFS (HR = 2.28).

Conclusion: In this cohort, CD33 and CD13 are the most frequent aberrant markers; importantly, CD33 expression serves as a significant independent predictor for relapse. CD33 expression may identify a higher-risk subgroup that could benefit from closer monitoring and risk-adapted therapeutic strategies to improve long-term outcomes in children with B-ALL.