Dissection of the pre-germinal center B-cell maturation pathway in common variable immunodeficiency based on standardized flow cytometric EuroFlow tools

Copyright © 2021 del Pino-Molina, López-Granados, Lecrevisse, Torres Canizales, Pérez-Andrés, Blanco, Wentink, Bonroy, Nechvatalova, Milota, Kienzler, Philippé, Sousa, van der Burg, Kalina, van Dongen and Orfao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Introduction: Common Variable Immunodeficiency (CVID) is characterized by defective antibody production and hypogammaglobulinemia. Flow cytometry immunophenotyping of blood lymphocytes has become of great relevance for the diagnosis and classification of CVID, due to an impaired differentiation of mature post-germinal-center (GC) class-switched memory B-cells (MBC) and severely decreased plasmablast/plasma cell (Pb) counts. Here, we investigated in detail the pre-GC B-cell maturation compartment in blood of CVID patients. Methods: In this collaborative multicentric study the EuroFlow PID 8-color Pre-GC B-cell tube, standardized sample preparation procedures (SOPs) and innovative data analysis tools, were used to characterize the maturation profile of pre-GC B-cells in 100 CVID patients, vs 62 age-matched healthy donors (HD). Results: The Pre-GC B-cell tube allowed identification within pre-GC B-cells of three subsets of maturation associated immature B-cells and three subpopulations of mature naïve B-lymphocytes. CVID patients showed overall reduced median absolute counts (vs HD) of the two more advanced stages of maturation of both CD5+ CD38+/++ CD21het CD24++ (2.7 vs 5.6 cells/µl, p=0.0004) and CD5+ CD38het CD21+ CD24+ (6.5 vs 17 cells/µl, p1 (CD38, CD5, CD19, CD21, CD24, and/or smIgM) phenotypic marker (57/88 patients; 65%) for a total of 3 distinct CVID patient profiles (group 1: 42/88 patients, 48%; group 2: 8/88, 9%; and group 3: 7/88, 8%) and ii) CVID patients with a clearly altered pre-GC B cell maturation pathway in blood (group 4: 31/88 cases, 35%). Conclusion: Our results show that maturation of pre-GC B-cells in blood of CVID is systematically altered with up to four distinctly altered maturation profiles. Further studies, are necessary to better understand the impact of such alterations on the post-GC defects and the clinical heterogeneity of CVID.The coordination and innovation processes of this study were supported by the EuroFlow Consortium (Chairmen: MB and AO). LP-M was supported by FIS PI16/01605 and JTC by FIS PI13/02296 (Fondo de Investigación Sanitaria Instituto de Salud Carlos III, Madrid, Spain). The work was partially supported by grant PI20/01712-FEDER (Fondo de Investigación Sanitaria Instituto de Salud Carlos III, Madrid, Spain) and a grant from Fundación Mutua Madrileña (MMA, Madrid, Spain).info:eu-repo/semantics/publishedVersio

Blood monitoring of circulating tumor plasma cells by next generation flow in multiple myeloma after therapy

Stemcel biology/Regenerative medicine (incl. bloodtransfusion