Laboratory Concordance and Prognostic Impact of 10-Color Flow Cytometry and Next-Generation Sequencing-Based Immunoglobulin Gene Assay for Measurable Residual Disease Monitoring in Adult B-Cell Acute Lymphoblastic Leukemia: A Multicenter Study From Thai Acute Leukemia Working Group (TALWG).
In a prospective multicenter cohort of 51 adults with newly diagnosed B-ALL, 10-color flow cytometry and NGS-based IGH testing showed 80.7% overall MRD concordance, while MRD positivity at three months—particularly by flow cytometry—predicted inferior relapse-free survival.
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In a prospective multicenter cohort of 51 adults with newly diagnosed B-ALL, 10-color flow cytometry and NGS-based IGH testing showed 80.7% overall MRD concordance, while MRD positivity at three months—particularly by flow cytometry—predicted inferior relapse-free survival.
Research significance
The study provides evidence that three-month MRD status can stratify relapse risk in adult B-ALL; it supports, but does not test, the inference that adapting therapy or transplantation decisions according to MRD—potentially using flow cytometry where NGS is unavailable—could improve outcomes.
Source abstract
AIMS: Measurable residual disease (MRD) is a key prognostic marker for patient survival. This study evaluated concordance between 10-color flow cytometry and next-generation sequencing (NGS)-based immunoglobulin heavy chain (IGH) gene assays for MRD detection and to assess prognostic significance in adult B-cell acute lymphoblastic leukemia (B-ALL). METHODS: This multicenter prospective study enrolled 51 patients with newly diagnosed B-ALL. Bone marrow samples were obtained at diagnosis, post-induction (1 month), and post-early consolidation (3 months). Flow cytometry and NGS-IGH were performed at three timepoints to assess MRD B-ALL. RESULTS: Patients were classified as high risk according to white blood cell count and cytogenetic features in 37.3% and 64.7% of patients, respectively. Treatment protocols included pediatric-inspired regimens (41.2%), adult-ALL protocols (52.9%), and low-intensity chemotherapy. All 16 Philadelphia chromosome-positive patients received tyrosine kinase inhibitors. Twenty patients underwent allogeneic hematopoietic cell transplantation (HCT) in first complete remission (CR). Median relapse-free survival (RFS) and overall survival were 19 and 39 months, respectively. MRD negativity at 3 months by either method correlated with significantly superior RFS. Allogeneic HCT also conferred RFS benefit. MRD positive patients without HCT had the worst RFS. Flow cytometry MRD positivity at 3 months independently predicted inferior RFS (HR 3.81; 95% CI 1.01-14.43). The overall concordance between flow cytometry and NGS was 80.7%. CONCLUSION: MRD positivity at 3 months post-treatment strongly predicted relapse, supporting its use to guide therapeutic modifications of B-ALL. Apart from NGS-based IGH clonality assays, 10-color flow cytometry offers an alternative in resource-limited settings.