Factors affecting chemotherapy response after the first relapse of B-cell acute lymphoblastic leukemia in pediatric patients.

OBJECTIVE: To investigate the factors affecting chemotherapy efficacy following first relapse in pediatric B-cell acute lymphoblastic leukemia (B-ALL). METHODS: A retrospective investigation was conducted on the clinical data from 254 pediatric patients with B-ALL treated at the First Affiliated Hospital of Xinjiang Medical University, Red Star Hospital of the 13th Division of Xinjiang Production and Construction Corps and Chengdu Women's and Children's Central Hospital between August 2016 and September 2022. Patients were divided into a Good Response (GR) group and a Poor Response (PR) group based on minimal residual disease (MRD) levels post-relapse treatment. The demographic data, blood and cytokine profiles, cytogenetic/molecular alterations, and therapeutic interventions were analyzed. Factors influencing response were screened using univariate and multivariate logistic regression models. RESULTS: The GR group showed significantly higher white blood cell (WBC) counts (8.24 ± 2.21 × 10(3)/µL) compared to the PR group (7.50 ± 1.88 × 10(3)/µL; P = 0.004). Elevated levels of tumor necrosis factor-alpha (TNF-α) (22.78 ± 4.31 vs. 20.94 ± 4.28 pg/mL; P < 0.001) and interleukin-6 (IL-6) (112.48 ± 21.09 vs. 106.31 ± 20.77 pg/mL; P = 0.020) were linked to poor outcome. Hypodiploidy and combined genetic alterations in Ikaros family zinc finger 1 (IKZF1), nuclear receptor subfamily 3 group C member 1 (NR3C1), and B-cell translocation gene 1 (BTG1) were associated with poor response (P = 0.032 and P = 0.003, respectively). Blinatumomab usage was associated with improved outcome (P = 0.030). Multivariate analysis revealed that higher TNF-α and IL-6 levels were independent risk factors of PR, while higher WBC count was a protective factor. CONCLUSION: Chemotherapy efficacy in relapsed pediatric B-ALL is influenced by hematologic, cytokine, and genetic factors.