EuroFlow Lymphoid Screening Tube (LST) data base for automated identification of blood lymphocyte subsets

In recent years the volume and complexity of flow cytometry data has increased substantially. This has led to a greater number of identifiable cell populations in a single measurement. Consequently, new gating strategies and new approaches for cell population definition are required. Here we describe how the EuroFlow Lymphoid Screening Tube (LST) reference data base for peripheral blood (PB) samples was designed, constructed and validated for automated gating of the distinct lymphoid (and myeloid) subsets in PB of patients with chronic lymphoproliferative disorders (CLPD). A total of 46 healthy/reactive PB samples which fulfilled predefined technical requirements, were used to construct the LST-PB reference data base. In addition, another set of 92 PB samples (corresponding to 10 healthy subjects, 51 B-cell CLPD and 31 T/NK-cell CLPD patients), were used to validate the automated gating and cell-population labeling tools with the Infinicyt software. An overall high performance of the LST-PB data base was observed with a median percentage of alarmed cellular events of 0.8% in 10 healthy donor samples and of 44.4% in CLPD data files containing 49.8% (range: 1.3–96%) tumor cells. The higher percent of alarmed cellular events in every CLPD sample was due to aberrant phenotypes (75.6% cases) and/or to abnormally increased cell counts (86.6% samples). All 18 (22%) data files that only displayed numerical alterations, corresponded to T/NK-cell CLPD cases which showed a lower incidence of aberrant phenotypes (41%) vs B-cell CLPD cases (100%). Comparison between automated vs expert-bases manual classification of normal (r2 = 0.96) and tumor cell populations (rho = 0.99) showed a high degree of correlation. In summary, our results show that automated gating of cell populations based on the EuroFlow LST-PB data base provides an innovative, reliable and reproducible tool for fast and simplified identification of normal vs pathological B and T/NK lymphocytes in PB of CLPD patients

Pericardial and myocardial involvement after SARS-CoV-2 infection: a cross-sectional descriptive study in healthcare workers

[ES] Introducción y objetivos Las secuelas cardiacas tras la infección por SARS-CoV-2 todavía están poco documentadas. Se realizó un estudio transversal en trabajadores sanitarios para estudiar la prevalencia de afección pericárdica y miocárdica tras la infección por SARS-CoV-2. Métodos Se estudió a 139 trabajadores sanitarios con infección previa confirmada por SARS-CoV-2. Los participantes se sometieron a evaluación clínica, electrocardiograma, laboratorio, incluido el perfil de células inmunitarias, y resonancia magnética cardiaca (RMC). El diagnóstico clínico de pericarditis se realizó ante la presencia de los criterios clásicos y el diagnóstico clínico de miocarditis ante la presencia de al menos 2 criterios de RMC. Resultados La mediana de edad fue de 52 (41–57) años, el 71,9% eran mujeres, y el 16,5% había sido hospitalizado previamente por neumonía por COVID-19. En la evaluación (10,4 [9,3–11,0] semanas después de los síntomas de infección), todos los participantes presentaban estabilidad hemodinámica. El 41,7% presentaba dolor torácico, disnea o palpitaciones; el 49,6%, alteraciones electrocardiográficas; el 7,9%, elevación de NT-proBNP; el 0,7%, elevación de troponina; y el 60,4%, alteraciones en la RMC. Un total de 30,9% de participantes cumplieron los criterios clínicos establecidos de pericarditis o miocarditis: pericarditis aislada en el 5,8%, miopericarditis en el 7,9% y miocarditis aislada en el 17,3%. La mayoría de los participantes (73,2%) mostraron recuentos de células inmunitarias alterados en sangre; en particular diminución de eosinófilos (27,3%; p < 0,001) y aumento del número de células T citotóxicas (17,3%; p < 0,001). La sospecha clínica de pericarditis se asoció (p < 0,005) particularmente con un elevado número de células T citotóxicas y recuento de eosinófilos disminuidos; mientras que los participantes con sospecha clínica de miopericarditis o miocarditis tenían recuentos de neutrófilos, células natural killer y células plasmáticas más bajos (p < 0,05). Conclusiones La afección pericárdica y miocárdica con estabilidad hemodinámica es frecuente después de la infección por SARS-CoV-2 y se asocia con perfiles de células inmunitarias específicas.[EN] Introduction and objectives The cardiac sequelae of SARS-CoV-2 infection are still poorly documented. We conducted a cross-sectional study in healthcare workers to report evidence of pericardial and myocardial involvement after SARS-CoV-2 infection. Methods We studied 139 healthcare workers with confirmed past SARS-CoV-2 infection. Participants underwent clinical assessment, electrocardiography, and laboratory tests, including immune cell profiling and cardiac magnetic resonance (CMR). Clinically suspected pericarditis was diagnosed when classic criteria were present and clinically suspected myocarditis was based on the combination of at least 2 CMR criteria. Results Median age was 52 (41-57) years, 71.9% were women, and 16.5% were previously hospitalized for COVID-19 pneumonia. On examination (10.4 [9.3-11.0] weeks after infection-like symptoms), participants showed hemodynamic stability. Chest pain, dyspnea or palpitations were present in 41.7% participants, electrocardiographic abnormalities in 49.6%, NT-proBNP elevation in 7.9%, troponin in 0.7%, and CMR abnormalities in 60.4%. A total of 30.9% participants met criteria for either pericarditis and/or myocarditis: isolated pericarditis was diagnosed in 5.8%, myopericarditis in 7.9%, and isolated myocarditis in 17.3%. Most participants (73.2%) showed altered immune cell counts in blood, particularly decreased eosinophil (27.3%; P < .001) and increased cytotoxic T cell numbers (17.3%; P < .001). Clinically suspected pericarditis was associated (P < .005) with particularly elevated cytotoxic T cells and decreased eosinophil counts, while participants diagnosed with clinically suspected myopericarditis or myocarditis had lower (P < .05) neutrophil counts, natural killer-cells, and plasma cells. Conclusions Pericardial and myocardial involvement with clinical stability are frequent after SARS-CoV-2 infection and are associated with specific immune cell profiles.Este estudio contó con el apoyo de CIBERCV (CB16/11/00374) y CIBERONC (CB16/12/00400) y la subvención COV20/00386 del Instituto de Salud Carlos III y FEDER, Ministerio de Ciencia e Innovación, Madrid, España, y por GRS COVID 26/A/20 de la Gerencia Regional de Salud, Junta de Castilla y León, España.Peer reviewe

Afección pericárdica y miocárdica tras infección por SARS-CoV-2: estudio descriptivo transversal en trabajadores sanitarios

[EN] Introduction and objectives The cardiac sequelae of SARS-CoV-2 infection are still poorly documented. We conducted a cross-sectional study in healthcare workers to report evidence of pericardial and myocardial involvement after SARS-CoV-2 infection. Methods We studied 139 healthcare workers with confirmed past SARS-CoV-2 infection. Participants underwent clinical assessment, electrocardiography, and laboratory tests, including immune cell profiling and cardiac magnetic resonance (CMR). Clinically suspected pericarditis was diagnosed when classic criteria were present and clinically suspected myocarditis was based on the combination of at least 2 CMR criteria. Results Median age was 52 (41-57) years, 71.9% were women, and 16.5% were previously hospitalized for COVID-19 pneumonia. On examination (10.4 [9.3-11.0] weeks after infection-like symptoms), participants showed hemodynamic stability. Chest pain, dyspnea or palpitations were present in 41.7% participants, electrocardiographic abnormalities in 49.6%, NT-proBNP elevation in 7.9%, troponin in 0.7%, and CMR abnormalities in 60.4%. A total of 30.9% participants met criteria for either pericarditis and/or myocarditis: isolated pericarditis was diagnosed in 5.8%, myopericarditis in 7.9%, and isolated myocarditis in 17.3%. Most participants (73.2%) showed altered immune cell counts in blood, particularly decreased eosinophil (27.3%; P < .001) and increased cytotoxic T cell numbers (17.3%; P < .001). Clinically suspected pericarditis was associated (P < .005) with particularly elevated cytotoxic T cells and decreased eosinophil counts, while participants diagnosed with clinically suspected myopericarditis or myocarditis had lower (P < .05) neutrophil counts, natural killer-cells, and plasma cells. Conclusions Pericardial and myocardial involvement with clinical stability are frequent after SARS-CoV-2 infection and are associated with specific immune cell profiles.[ES] Introducción y objetivos Las secuelas cardiacas tras la infección por SARS-CoV-2 todavía están poco documentadas. Se realizó un estudio transversal en trabajadores sanitarios para estudiar la prevalencia de afección pericárdica y miocárdica tras la infección por SARS-CoV-2. Métodos Se estudió a 139 trabajadores sanitarios con infección previa confirmada por SARS-CoV-2. Los participantes se sometieron a evaluación clínica, electrocardiograma, laboratorio, incluido el perfil de células inmunitarias, y resonancia magnética cardiaca (RMC). El diagnóstico clínico de pericarditis se realizó ante la presencia de los criterios clásicos y el diagnóstico clínico de miocarditis ante la presencia de al menos 2 criterios de RMC. Resultados La mediana de edad fue de 52 (41–57) años, el 71,9% eran mujeres, y el 16.5% había sido hospitalizado previamente por neumonía por COVID-19. En la evaluación (10,4 [9,3–11,0] semanas después de los síntomas de infección), todos los participantes presentaban estabilidad hemodinámica. El 41,7% presentaba dolor torácico, disnea o palpitaciones; el 49,6%, alteraciones electrocardiográficas; el 7,9%, elevación de NT-proBNP; el 0,7%, elevación de troponina; y el 60,4%, alteraciones en la RMC. Un total de 30,9% de participantes cumplieron los criterios clínicos establecidos de pericarditis o miocarditis: pericarditis aislada en el 5,8%, miopericarditis en el 7,9% y miocarditis aislada en el 17,3%. La mayoría de los participantes (73,2%) mostraron recuentos de células inmunitarias alterados en sangre; en particular diminución de eosinófilos (27,3%; p < 0,001) y aumento del número de células T citotóxicas (17,3%; p < 0,001). La sospecha clínica de pericarditis se asoció (p < 0,005) particularmente con un elevado número de células T citotóxicas y recuento de eosinófilos disminuidos; mientras que los participantes con sospecha clínica de miopericarditis o miocarditis tenían recuentos de neutrófilos, células natural killer y células plasmáticas más bajos (p < 0,05). Conclusiones La afección pericárdica y miocárdica con estabilidad hemodinámica es frecuente después de la infección por SARS-CoV-2 y se asocia con perfiles de células inmunitarias específicas.This study was supported by CIBERCV (CB16/11/00374), CIBERONC (CB16/12/00400) and the COV20/00386 grant from the Instituto de Salud Carlos III and FEDER, Ministerio de Ciencia e Innovación, Madrid, Spain, and by GRS COVID 26/A/20 from the Gerencia Regional de Salud, Junta de Castilla y León, Spain.Peer reviewe

Expert-independent classification of mature B-cell neoplasms using standardized flow cytometry: a multicentric study

Reproducible expert-independent flow-cytometric criteria for the differential diagnoses between mature B-cell neoplasms are lacking. We developed an algorithm-driven classification for these lymphomas by flow cytometry and compared it to the WHO gold standard diagnosis. Overall, 662 samples from 662 patients representing 9 disease categories were analyzed at 9 laboratories using the previously published EuroFlow 5-tube-8-color B-cell chronic lymphoproliferative disease antibody panel. Expression levels of all 26 markers from the panel were plotted by B-cell entity to construct a univariate, fully standardized diagnostic reference library. For multivariate data analysis, we subsequently used canonical correlation analysis of 176 training cases to project the multidimensional space of all 26 immunophenotypic parameters into 36 2-dimensional plots for each possible pairwise differential diagnosis. Diagnostic boundaries were fitted according to the distribution of the immunophenotypes of a given differential diagnosis. A diagnostic algorithm based on these projections was developed and subsequently validated using 486 independent cases. Negative predictive values exceeding 92.1% were observed for all disease categories except for follicular lymphoma. Particularly high positive predictive values were returned in chronic lymphocytic leukemia (99.1%), hairy cell leukemia (97.2%), follicular lymphoma (97.2%), and mantle cell lymphoma (95.4%). Burkitt and CD101 diffuse large B-cell lymphomas were difficult to distinguish by the algorithm. A similar ambiguity was observed between marginal zone, lymphoplasmacytic, and CD102 diffuse large B-cell lymphomas. The specificity of the approach exceeded 98% for all entities. The univariate immunophenotypic library and the multivariate expert-independent diagnostic algorithm might contribute to increased reproducibility of future diagnostics in mature B-cell neoplasms

Pericarditis and myocarditis long after SARS-CoV-2 infection: a cross-sectional descriptive study in health-care workers

Background: Cardiac sequelae of past SARS-CoV-2 infection are still poorly documented. We conducted a cross-sectional study in health-care workers to report evidence of pericarditis and myocarditis after SARS-CoV-2 infection.Methods We studied 139 health-care workers with confirmed past SARS-CoV-2 infection (103 diagnosed by RT-PCR and 36 by serology). Participants underwent clinical assessment, electrocardiography, laboratory tests including immune cell profiling and cardiac magnetic resonance (CMR) imaging. Pericarditis was diagnosed when classical criteria were present, and the diagnosis of myocarditis was based on the updated CMR Lake-Louise-Criteria.Results: Median age was 52 years (IQR 41-57), 100 (72%) were women, and 23 (16%) were previously hospitalized for Covid-19 pneumonia. At examination (10.4 [9.3-11.0] weeks after infection-like symptoms), all participants presented hemodynamic stability. Chest pain, dyspnoea or palpitations were observed in 58 (42%) participants; electrocardiographic abnormalities in 69 (50%); NT-pro-BNP was elevated in 11 (8%); troponin in 1 (1%); and CMR abnormalities in 104 (75%). Isolated pericarditis was diagnosed in 4 (3%) participants, myopericarditis in 15 (11%) and isolated myocarditis in 36 (26%). Participants diagnosed by RT-PCR were more likely to still present symptoms than participants diagnosed by serology (73 [71%] vs 18 [50%]; p=0.027); nonetheless, the prevalence of pericarditis or myocarditis was high in both groups (44 [43%] vs 11 [31%]; p=0.238). Most participants (101 [73%]) showed altered immune cell counts in blood, particularly decreased eosinophil (37 [27%]; p<0.001) and increased CD4-CD8-/loT alpha beta-cell numbers (24 [17%]; p<0.001). Pericarditis was associated with elevated CD4-CD8-/loT alpha beta-cell numbers (p=0.011), while participants diagnosed with myopericarditis or myocarditis had lower (p<0.05) plasmacytoid dendritic cell, NK-cell and plasma cell counts and lower anti-SARS-CoV-2-IgG antibody levels (p=0.027).Conclusions: Pericarditis and myocarditis with clinical stability are frequent long after SARS-CoV-2 infection, even in presently asymptomatic subjects. These observations will probably apply to the general population infected and may indicate that cardiac sequelae might occur late in association with an altered (delayed) innate and adaptative immune response.This study was supported by CIBERCV (CB16/11/00374), CIBERONC (CB16/12/00400) and the COV20/00386 grant from the Instituto de Salud Carlos III and FEDER, Ministerio de Ciencia e Innovacion, Madrid, Spain.N

EuroFlow Lymphoid Screening Tube (LST) data base for automated identification of blood lymphocyte subsets

© 2019 The Authors.In recent years the volume and complexity of flow cytometry data has increased substantially. This has led to a greater number of identifiable cell populations in a single measurement. Consequently, new gating strategies and new approaches for cell population definition are required. Here we describe how the EuroFlow Lymphoid Screening Tube (LST) reference data base for peripheral blood (PB) samples was designed, constructed and validated for automated gating of the distinct lymphoid (and myeloid) subsets in PB of patients with chronic lymphoproliferative disorders (CLPD). A total of 46 healthy/reactive PB samples which fulfilled pre-defined technical requirements, were used to construct the LST-PB reference data base. In addition, another set of 92 PB samples (corresponding to 10 healthy subjects, 51 B-cell CLPD and 31 T/NK-cell CLPD patients), were used to validate the automated gating and cell-population labeling tools with the Infinicyt software. An overall high performance of the LST-PB data base was observed with a median percentage of alarmed cellular events of 0.8% in 10 healthy donor samples and of 44.4% in CLPD data files containing 49.8% (range: 1.3–96%) tumor cells. The higher percent of alarmed cellular events in every CLPD sample was due to aberrant phenotypes (75.6% cases) and/or to abnormally increased cell counts (86.6% samples). All 18 (22%) data files that only displayed numerical alterations, corresponded to T/NK-cell CLPD cases which showed a lower incidence of aberrant phenotypes (41%) vs B-cell CLPD cases (100%). Comparison between automated vs expert-bases manual classification of normal (r2 = 0.96) and tumor cell populations (rho = 0.99) showed a high degree of correlation. In summary, our results show that automated gating of cell populations based on the EuroFlow LST-PB data base provides an innovative, reliable and reproducible tool for fast and simplified identification of normal vs pathological B and T/NK lymphocytes in PB of CLPD patients.This work was supported by the CB16/12/00400 and CB16/12/00369 grants, CIBER-ONC, Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain and FONDOS FEDER; DTS 15/00119 grant, Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain and FONDOS FEDER; and, RETOS (RTC–2016–4865–1) grant, Sociedad de la Acción Estratégica de Economía y Sociedad Digital-Impulso Tecnológico; Ministerio de Economía y Competitividad, Madrid, Spain

EuroFlow Lymphoid Screening Tube (LST) data base for automated identification of blood lymphocyte subsets

In recent years the volume and complexity of flow cytometry data has increased substantially. This has led to a greater number of identifiable cell populations in a single measurement. Consequently, new gating strategies and new approaches for cell population definition are required. Here we describe how the EuroFlow Lymphoid Screening Tube (LST) reference data base for peripheral blood (PB) samples was designed, constructed and validated for automated gating of the distinct lymphoid (and myeloid) subsets in PB of patients with chronic lymphoproliferative disorders (CLPD). A total of 46 healthy/reactive PB samples which fulfilled predefined technical requirements, were used to construct the LST-PB reference data base. In addition, another set of 92 PB samples (corresponding to 10 healthy subjects, 51 B-cell CLPD and 31 T/NK-cell CLPD patients), were used to validate the automated gating and cell-population labeling tools with the Infinicyt software. An overall high performance of the LST-PB data base was observed with a median percentage of alarmed cellular events of 0.8% in 10 healthy donor samples and of 44.4% in CLPD data files containing 49.8% (range: 1.3–96%) tumor cells. The higher percent of alarmed cellular events in every CLPD sample was due to aberrant phenotypes (75.6% cases) and/or to abnormally increased cell counts (86.6% samples). All 18 (22%) data files that only displayed numerical alterations, corresponded to T/NK-cell CLPD cases which showed a lower incidence of aberrant phenotypes (41%) vs B-cell CLPD cases (100%). Comparison between automated vs expert-bases manual classification of normal (r2 = 0.96) and tumor cell populations (rho = 0.99) showed a high degree of correlation. In summary, our results show that automated gating of cell populations based on the EuroFlow LST-PB data base provides an innovative, reliable and reproducible tool for fast and simplified identification of normal vs pathological B and T/NK lymphocytes in PB of CLPD patients

Expert-independent classification of mature B-cell neoplasms using standardized flow cytometry: a multicentric study

Reproducible expert-independent flow-cytometric criteria for the differential diagnoses between mature B-cell neoplasms are lacking. We developed an algorithm-driven classification for these lymphomas by flow cytometry and compared it to the WHO gold standard diagnosis. Overall, 662 samples from 662 patients representing 9 disease categories were analyzed at 9 laboratories using the previously published EuroFlow 5-tube-8-color B-cell chronic lymphoproliferative disease antibody panel. Expression levels of all 26 markers from the panel were plotted by B-cell entity to construct a univariate, fully standardized diagnostic reference library. For multivariate data analysis, we subsequently used canonical correlation analysis of 176 training cases to project the multidimensional space of all 26 immunophenotypic parameters into 36 2-dimensional plots for each possible pairwise differential diagnosis. Diagnostic boundaries were fitted according to the distribution of the immunophenotypes of a given differential diagnosis. A diagnostic algorithm based on these projections was developed and subsequently validated using 486 independent cases. Negative predictive values exceeding 92.1% were observed for all disease categories except for follicular lymphoma. Particularly high positive predictive values were returned in chronic lymphocytic leukemia (99.1%), hairy cell leukemia (97.2%), follicular lymphoma (97.2%), and mantle cell lymphoma (95.4%). Burkitt and CD101 diffuse large B-cell lymphomas were difficult to distinguish by the algorithm. A similar ambiguity was observed between marginal zone, lymphoplasmacytic, and CD102 diffuse large B-cell lymphomas. The specificity of the approach exceeded 98% for all entities. The univariate immunophenotypic library and the multivariate expert-independent diagnostic algorithm might contribute to increased reproducibility of future diagnostics in mature B-cell neoplasms

Next generation flow for highly sensitive and standardized detection of minimal residual disease in multiple myeloma

Flow cytometry has become a highly valuable method to monitor minimal residual disease (MRD) and evaluate the depth of complete response (CR) in bone marrow (BM) of multiple myeloma (MM) after therapy. However, current flow-MRD has lower sensitivity than molecular methods and lacks standardization. Here we report on a novel next generation flow (NGF) approach for highly sensitive and standardized MRD detection in MM. An optimized 2-tube 8-color antibody panel was constructed in five cycles of design-evaluation-redesign. In addition, a bulk-lysis procedure was established for acquisition of ⩾107 cells/sample, and novel software tools were constructed for automatic plasma cell gating. Multicenter evaluation of 110 follow-up BM from MM patients in very good partial response (VGPR) or CR showed a higher sensitivity for NGF-MRD vs conventional 8-color flow-MRD -MRD-positive rate of 47 vs 34% (P=0.003)-. Thus, 25% of patients classified as MRD-negative by conventional 8-color flow were MRD-positive by NGF, translating into a significantly longer progression-free survival for MRD-negative vs MRD-positive CR patients by NGF (75% progression-free survival not reached vs 7 months; P=0.02). This study establishes EuroFlow-based NGF as a highly sensitive, fully standardized approach for MRD detection in MM which overcomes the major limitations of conventional flow-MRD methods and is ready for implementation in routine diagnostics.This work has been supported by the International Myeloma Foundation-Black Swan Research Initiative, the Red Temática de Investigación Cooperativa en Cáncer (RTICC); grant SA079U14 from the Consejería de Educación, Junta de Castilla y León, Valladolid, Spain and; grant DTS15/00119 from Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain.Peer Reviewe