Flow-cytometric MRD detection in pediatric T-ALL: a multicenter AIEOP-BFM consensus-based guided standardized
Michaela Reiterová1,2,3, Saskia Kohlscheen4, Oscar Maglia5
1CLIP (Childhood Leukaemia Investigation Prague), Prague, Czech Republic.
Objectives:
Risk-based stratification approaches using measurable residual disease (MRD) successfully help to identify T-acute lymphoblastic leukemia (T-ALL) patients at risk of relapse, whose treatment outcomes are very poor. Because of T-ALL heterogeneity and rarity, a reliable and standardized approach for flow cytometry (FC)-based MRD measurement and analysis is often missing.
Methods:
Within the international AIEOP-BFM-ALL-FLOW study group we made a consensus on markers and a standard operating procedure for common 8- and 12-color T-ALL MRD panels. Custom manufactured tubes with dried backbone antibodies were tested in parallel to local FC standards.
Results:
Altogether, 66 diagnostic and 67 day 15 samples were analyzed. We designed two guided MRD gating strategies to identify blast cells in parallel to expert-based evaluation. We proved that the optimized tubes allowed the correct identification of blast cells in all diagnostic samples. Both, expert and guided analysis of day 15 samples correlated to local standard (Spearman R=0.98 and R=0.94, respectively). Only in 2 (3 %) and 4 (6 %) patients expert gating and guided analysis results were substantially discordant from local standard, respectively. The cases that require an individualized approach may be partially identified at diagnosis through a rare immunophenotype or mixed phenotype acute leukemia status.
Conclusions:
Our work shows that standardized operating procedures together with guided analysis are applicable in a great majority of T-ALL cases. Further improvement of MRD detection is needed, as in some cases an individualized analytical approach is still required due to the challenging nature of the T-ALL phenotype.
Insights
Standardized flow cytometry protocols effectively identify measurable residual disease (MRD) in T-acute lymphoblastic leukemia (T-ALL) patients, aiding risk stratification. This approach improves MRD detection for most T-ALL cases, though some require individualized analysis.
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.
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