T-regulatory cells and their clinico-pathological correlation in pediatric B-cell acute lymphoblastic leukemia: An observational study

Objectives: The objective of the study is to evaluate regulatory T-cell (Treg) levels in pediatric B-cell acute lymphoblastic leukemia (B-ALL) at diagnosis and after induction chemotherapy and to assess their association with clinico-hematological parameters and treatment response. Materials and Methods: This prospective observational study was conducted from October 2023 to March 2025 and included 39 children (<18 years) newly diagnosed with precursor B-ALL. Peripheral blood Tregs were quantified at baseline and after induction chemotherapy using flow cytometry with CD45, CD4, CD25, and Foxp3 markers. Clinical characteristics, hematological parameters, risk stratification, and treatment response were documented. Statistical analysis: Comparisons between baseline and post-induction values were performed using the Wilcoxon signed-rank test. Associations between variables were analyzed using Spearman correlation, Kruskal–Wallis test, and Mann–Whitney U test. A p <0.05 was considered statistically significant. Results: Treg levels showed a significant reduction following induction chemotherapy ( p <0.001). Post-induction Treg levels were significantly higher in females compared with males ( p = 0.044). CD4 + T-cell levels increased significantly after induction therapy ( p = 0.0313). No significant associations were observed between Treg levels (baseline, post-induction, or change) and age, hematological parameters, risk category, or treatment response. Conclusions: Induction chemotherapy results in a significant decline in Treg levels in pediatric B-ALL, with a notable gender-based difference observed after treatment. Larger longitudinal studies are warranted to determine the potential role of Tregs as biomarkers and therapeutic targets in B-ALL.