PURPOSE: The International Berlin-Frankfurt-Münster (BFM) study group conducted a study on pediatric acute lymphoblastic leukemia (ALL). Minimal residual disease (MRD) was assessed using flow cytometry (FCM), and the impact of early intensification and methotrexate (MTX) dose on survival was evaluated. PATIENTS AND METHODS: We included 6,187 patients younger than 19 years. MRD by FCM refined the risk group definition previously used in the ALL intercontinental-BFM 2002 study on the basis of age, WBC count, unfavorable genetic aberrations, and treatment response measured morphologically. Patients at intermediate risk (IR) and high risk (HR) were randomly assigned to protocol augmented protocol I phase B (IB) versus IB regimen. MTX doses of 2 versus 5 g/m2 every 2 weeks, four times, were evaluated in precursor B-cell-ALL (pcB-ALL) IR. RESULTS: The 5-year event-free survival (EFS ± SE) and overall survival (OS ± SE) rates were 75.2% ± 0.6% and 82.6% ± 0.5%, respectively. Their values in risk groups were standard risk (n = 624), 90.7% ± 1.4% and 94.7% ± 1.1%; IR (n = 4,111), 77.9% ± 0.7% and 85.7% ± 0.6%; and HR (n = 1,452), 60.8% ± 1.5% and 68.4% ± 1.4%, respectively. MRD by FCM was available in 82.6% of cases. The 5-year EFS rates in patients randomly assigned to protocol IB (n = 1,669) and augmented IB (n = 1,620) were 73.6% ± 1.2% and 72.8% ± 1.2%, respectively (P = .55), while those in patients receiving MTX doses of 2 g/m2 (n = 1,056) and MTX 5 g/m2 (n = 1,027) were 78.8% ± 1.4% and 78.9% ± 1.4%, respectively (P = .84). CONCLUSION: The MRDs were successfully assessed using FCM. An MTX dose of 2 g/m2 was effective in preventing relapse in non-HR pcB-ALL. Augmented IB showed no advantages over the standard IB.[Media: see text].

• MeSH
• akutní lymfatická leukemie * MeSH
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• methotrexát terapeutické užití   MeSH
• pre-B-buněčná leukemie * farmakoterapie   MeSH
• přežití po terapii bez příznaků nemoci MeSH
• protokoly antitumorózní kombinované chemoterapie terapeutické užití   MeSH
• rizikové faktory MeSH
• výsledek terapie MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• randomizované kontrolované studie MeSH

Given its myeloid-restricted expression, myeloperoxidase (MPO) is typically used for lineage assignment (myeloid vs. lymphoid) during acute leukaemia (AL) diagnostics. In the present study, a robust flow cytometric definition for MPO positivity was established based on the standardised EuroFlow protocols, the standardised Acute Leukaemia Orientation Tube and 1734 multicentre AL cases (with confirmed assay stability). The best diagnostic performance was achieved by defining MPO positivity as ≥20% of the AL cells exceeding a lymphocyte-based threshold. The methodology employed should be applicable to any form of standardised flow cytometry.

• MeSH
• akutní nemoc MeSH
• imunofenotypizace normy   MeSH
• leukemie * diagnóza   enzymologie   imunologie   MeSH
• lidé MeSH
• nádorové proteiny * krev   imunologie   MeSH
• peroxidasa * krev   imunologie   MeSH
• průtoková cytometrie normy   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH

A critical component of the EuroFlow standardization of leukemia/lymphoma immunophenotyping is instrument setup. Initially, the EuroFlow consortium developed a step-by-step standard operating protocol for instrument setup of ≥8-color flow cytometers that were available in 2006, when the EuroFlow activities started. Currently, there are 14 instruments from 9 manufacturers capable of 3-laser excitation and ≥8 color measurements. The specific adaptations required in the instrument set-up to enable them to acquire the standardized 8-color EuroFlow protocols are described here. Overall, all 14 instruments can be fitted with similar violet, blue and red lasers for simultaneous measurements of ≥8 fluorescent dyes. Since individual instruments differ both on their dynamic range (scale) and emission filters, it is not accurate to simply recalculate the target values to different scale, but adjustment of PMT voltages to a given emission filter and fluorochrome, is essential. For this purpose, EuroFlow has developed an approach using Type IIB (spectrally matching) particles to set-up standardized and fully comparable fluorescence measurements, in instruments from different manufacturers, as demonstrated here for the FACSCanto II, and Navios and MACSQuant flow cytometers. Data acquired after such adjustment on any of the tested cytometry platforms could be fully superimposed and therefore analyzed together. The proposed approach can be used to derive target values for any combination of spectrally distinct fluorochromes and any distinct emission filter of any new flow cytometry platform, which enables the measurement of the 8-color EuroFlow panels in a standardized way, by creating superimposable datafiles.

• MeSH
• hematologické nádory diagnóza   MeSH
• imunofenotypizace přístrojové vybavení   normy   MeSH
• lidé MeSH
• průtoková cytometrie přístrojové vybavení   normy   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Precise classification of acute leukemia (AL) is crucial for adequate treatment. EuroFlow has previously designed an AL orientation tube (ALOT) to guide towards the relevant classification panel (T-cell acute lymphoblastic leukemia (T-ALL), B-cell precursor (BCP)-ALL and/or acute myeloid leukemia (AML)) and final diagnosis. Now we built a reference database with 656 typical AL samples (145 T-ALL, 377 BCP-ALL, 134 AML), processed and analyzed via standardized protocols. Using principal component analysis (PCA)-based plots and automated classification algorithms for direct comparison of single-cells from individual patients against the database, another 783 cases were subsequently evaluated. Depending on the database-guided results, patients were categorized as: (i) typical T, B or Myeloid without or; (ii) with a transitional component to another lineage; (iii) atypical; or (iv) mixed-lineage. Using this automated algorithm, in 781/783 cases (99.7%) the right panel was selected, and data comparable to the final WHO-diagnosis was already provided in >93% of cases (85% T-ALL, 97% BCP-ALL, 95% AML and 87% mixed-phenotype AL patients), even without data on the full-characterization panels. Our results show that database-guided analysis facilitates standardized interpretation of ALOT results and allows accurate selection of the relevant classification panels, hence providing a solid basis for designing future WHO AL classifications.

• MeSH
• akutní lymfatická leukemie patologie   MeSH
• akutní myeloidní leukemie patologie   MeSH
• akutní nemoc MeSH
• dítě MeSH
• dospělí MeSH
• imunofenotypizace metody   MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A fully-standardized EuroFlow 8-color antibody panel and laboratory procedure was stepwise designed to measure minimal residual disease (MRD) in B-cell precursor (BCP) acute lymphoblastic leukemia (ALL) patients with a sensitivity of ≤10(-5), comparable to real-time quantitative polymerase chain reaction (RQ-PCR)-based MRD detection via antigen-receptor rearrangements. Leukocyte markers and the corresponding antibodies and fluorochromes were selected based on their contribution in separating BCP-ALL cells from normal/regenerating BCP cells in multidimensional principal component analyses. After 5 multicenter design-test-evaluate-redesign phases with a total of 319 BCP-ALL patients at diagnosis, two 8-color antibody tubes were selected, which allowed separation between normal and malignant BCP cells in 99% of studied patients. These 2 tubes were tested with a new erythrocyte bulk-lysis protocol allowing acquisition of high cell numbers in 377 bone marrow follow-up samples of 178 BCP-ALL patients. Comparison with RQ-PCR-based MRD data showed a clear positive relation between the percentage concordant cases and the number of cells acquired. For those samples with >4 million cells acquired, concordant results were obtained in 93% of samples. Most discordances were clarified upon high-throughput sequencing of antigen-receptor rearrangements and blind multicenter reanalysis of flow cytometric data, resulting in an unprecedented concordance of 98% (97% for samples with MRD < 0.01%). In conclusion, the fully standardized EuroFlow BCP-ALL MRD strategy is applicable in >98% of patients with sensitivities at least similar to RQ-PCR (≤10(-5)), if sufficient cells (>4 × 10(6), preferably more) are evaluated.

• MeSH
• dítě MeSH
• dospělí MeSH
• genová přestavba MeSH
• kojenec MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• novorozenec MeSH
• pre-B-buněčná leukemie diagnóza   MeSH
• předškolní dítě MeSH
• průtoková cytometrie metody   normy   MeSH
• receptory antigenů B-buněk genetika   MeSH
• reziduální nádor diagnóza   MeSH
• senioři MeSH
• senzitivita a specificita MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH