Flow-cytometric MRD detection in pediatric T-ALL: a multicenter AIEOP-BFM consensus-based guided standardized...

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• Measurable residual disease (MRD) monitoring is crucial for risk-based stratification in T-acute lymphoblastic leukemia (T-ALL).
• T-ALL exhibits heterogeneity and rarity, often lacking standardized flow cytometry (FC)-based MRD measurement methods.
• Poor treatment outcomes in relapsed T-ALL necessitate improved MRD detection and analysis.

Purpose of the Study:

• To establish a standardized operating procedure (SOP) for T-ALL MRD detection using flow cytometry.
• To develop and validate guided MRD gating strategies for T-ALL sample analysis.
• To assess the applicability of standardized MRD panels and guided analysis in a large international study group.

Main Methods:

• Consensus on markers and SOP for 8- and 12-color T-ALL MRD panels within the AIEOP-BFM-ALL-FLOW study group.
• Testing of custom manufactured tubes with dried backbone antibodies against local FC standards.
• Development of two guided MRD gating strategies for blast cell identification, compared to expert-based evaluation.

Main Results:

• Analysis of 66 diagnostic and 67 day 15 samples using standardized MRD panels.
• Optimized tubes correctly identified blast cells in all diagnostic samples.
• Expert and guided MRD analysis of day 15 samples showed high correlation with local standards (Spearman R=0.98 and R=0.94, respectively).
• Substantial discordance from local standards was minimal (3% for expert, 6% for guided analysis).

Conclusions:

• Standardized operating procedures and guided analysis are effective for the majority of T-ALL MRD cases.
• The developed approach demonstrates high applicability and correlation with existing standards.
• Individualized analytical approaches may still be necessary for a subset of T-ALL cases due to challenging phenotypes.