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Knight V, Starich O, Dutmer CM, Abbott JK. Longitudinal monitoring of class-switched memory-B cell proportions identifies plausible germinal center failure in patients with suspected immune disorders. CYTOMETRY. PART B, CLINICAL CYTOMETRY 2025; 108:222-233. [PMID: 39791256 DOI: 10.1002/cyto.b.22222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2024] [Revised: 12/18/2024] [Accepted: 12/27/2024] [Indexed: 01/12/2025]
Abstract
A reduced proportion of peripheral class-switched memory B cells (CSM-B cells) is presumed to indicate ineffective germinal activity. The extent that this finding corresponds to a plausible germinal center failure pathophysiology in patients not diagnosed with CVID or hyper IgM syndrome is not known. We asked if patients with low CSM-B cells are more likely to demonstrate failure to produce serum IgA and IgG than counterparts with nonreduced class-switched memory B cell levels, regardless of diagnosis. Patients with low CSM-B cell levels regardless of diagnosis were retrospectively compared with their counterparts without CSM-B cell reductions for demographics and serum immunoglobulin levels. Patients were further divided based on whether CSM-B cell levels remained low over time or fluctuated, and these groups were compared for serum immunoglobulin levels and diagnoses. Of 305 patients, those with CSM-B cell (n = 50) reductions were more likely to have low serum IgA and IgG than those without reductions. Of the 78 patients in whom CSM-B cells were measured repeatedly over time, 21 patients had low CSM-B cell levels, but this finding was persistent in only 10. Patients with persistent CSM-B cell reductions universally had severe serum IgA and IgG deficiencies and patients with transient CSM-B cell reduction often did not. These two groups contained divergent diagnoses and likely represent separate pathophysiologic groups. Quantifying CSM-B cells as a percentage of CD27+ B cells repeatedly over time is a robust approach to identifying patients with a plausible germinal center failure endotype.
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Affiliation(s)
- Vijaya Knight
- Department of Pediatrics, Section of Allergy and Immunology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Children's Hospital Colorado, Aurora, Colorado, USA
| | - Olivia Starich
- University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Cullen M Dutmer
- Department of Pediatrics, Section of Allergy and Immunology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Children's Hospital Colorado, Aurora, Colorado, USA
| | - Jordan K Abbott
- Department of Pediatrics, Section of Allergy and Immunology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Children's Hospital Colorado, Aurora, Colorado, USA
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Sadighi Akha AA, Csomós K, Ujházi B, Walter JE, Kumánovics A. Evolving Approach to Clinical Cytometry for Immunodeficiencies and Other Immune Disorders. Immunol Allergy Clin North Am 2025; 45:205-221. [PMID: 40287169 DOI: 10.1016/j.iac.2025.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2025]
Abstract
Primary immunodeficiencies were initially identified on the basis of recurrent, severe or unusual infections. Subsequently, it was noted that these diseases can also manifest with autoimmunity, autoinflammation, allergy, lymphoproliferation and malignancy, hence a conceptual change and their renaming as inborn errors of immunity. Ongoing advances in flow cytometry provide the opportunity to expand or modify the utility and scope of existing laboratory tests in this field to mirror this conceptual change. Here we have used the B cell subset, variably known as CD21low B cells, age-associated B cells and T-bet+ B cells, as an example to demonstrate this possibility.
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Affiliation(s)
- Amir A Sadighi Akha
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Krisztián Csomós
- Division of Pediatric Allergy/Immunology, University of South Florida, Johns Hopkins All Children's Hospital, St. Petersburg, FL, USA
| | - Boglárka Ujházi
- Division of Pediatric Allergy/Immunology, University of South Florida, Johns Hopkins All Children's Hospital, St. Petersburg, FL, USA
| | - Jolán E Walter
- Division of Pediatric Allergy/Immunology, University of South Florida, Johns Hopkins All Children's Hospital, St. Petersburg, FL, USA
| | - Attila Kumánovics
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
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Pinto TNC, Benard G, Fernandes JR. Phenotypic Characterization of B-Lymphocyte Subpopulations in Human Peripheral Blood: A Cost-Effective Seven-Color One-Tube Protocol. Methods Mol Biol 2025; 2857:15-31. [PMID: 39348052 DOI: 10.1007/978-1-0716-4128-6_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
B cells are crucial components of the immune system, responsible for producing specific antibodies in response to infections and vaccines. Despite their uniform appearance, B cells display diverse surface molecules and functional properties, which are not yet fully understood. Apart from antibody production, B cells also play roles in antigen presentation and cytokine secretion, essential for initiating T-cell immune responses. Their significance as disease biomarkers and therapeutic targets has led to increased research focus. However, the lack of standardized protocols for B-cell identification and the variability in defining B-lymphocyte subpopulations pose some challenges. This paper proposes a B-cell identification panel throughout the evaluation of previous cytometry panels and nomenclature heterogeneity for B-cell subpopulations. Major subpopulations recognized in human peripheral blood include transitional, naive, switched memory, unswitched memory, double negative, and plasmablasts, characterized based on their functional and phenotypic features. We present a standardized flow cytometry protocol utilizing surface phenotypic markers (CD3, CD19, IgD, CD27, CD38, and CD24) to differentiate and analyze B-cell subpopulations. This practical and cost-effective panel can be used in various research and laboratory settings. The challenges of standardizing names and markers for classifying B-lymphocyte subpopulations are discussed, along with protocols utilizing multiple markers and gating strategies, allied with the importance of considering viability markers. In summary, this standardized protocol and panel provide a comprehensive approach to identifying B-cell subpopulations to enhance the reproducibility and comparability of B-cell subpopulation studies.
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Affiliation(s)
- Thalyta Nery Carvalho Pinto
- Laboratory of Dermatology and Immunodeficiencies (LIM56), Tropical Medicine Institute (IMT), School of Medicine, São Paulo University, São Paulo, Brazil
| | - Gil Benard
- Laboratory of Dermatology and Immunodeficiencies (LIM56), Tropical Medicine Institute (IMT), School of Medicine, São Paulo University, São Paulo, Brazil
| | - Juliana Ruiz Fernandes
- Laboratory of Dermatology and Immunodeficiencies (LIM56), Tropical Medicine Institute (IMT), School of Medicine, São Paulo University, São Paulo, Brazil.
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Nalwoga A, Nakibuule M, Roshan R, Kwizera Mbonye M, Miley W, Whitby D, Newton R, Rochford R, Cose S. Immune cell phenotype and function patterns across the life course in individuals from rural Uganda. Front Immunol 2024; 15:1356635. [PMID: 38562926 PMCID: PMC10982424 DOI: 10.3389/fimmu.2024.1356635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/28/2024] [Indexed: 04/04/2024] Open
Abstract
Background To determine the pattern of immune cell subsets across the life span in rural sub-Saharan Africa (SSA), and to set a reference standard for cell subsets amongst Africans, we characterised the major immune cell subsets in peripheral blood including T cells, B cells, monocytes, NK cells, neutrophils and eosinophils, in individuals aged 3 to 89 years from Uganda. Methods Immune phenotypes were measured using both conventional flow cytometry in 72 individuals, and full spectrum flow cytometry in 80 individuals. Epstein-Barr virus (EBV) IFN-γ T cell responses were quantified in 332 individuals using an ELISpot assay. Full blood counts of all study participants were also obtained. Results The percentages of central memory (TCM) and senescent CD4+ and CD8+ T cell subsets, effector memory (TEM) CD8+ T cells and neutrophils increased with increasing age. On the other hand, the percentages of naïve T (TN) and B (BN) cells, atypical B cells (BA), total lymphocytes, eosinophils and basophils decreased with increasing age. There was no change in CD4+ or CD8+ T effector memory RA (TEMRA) cells, exhausted T cells, NK cells and monocytes with age. Higher eosinophil and basophil percentages were observed in males compared to females. T cell function as measured by IFN-γ responses to EBV increased with increasing age, peaking at 31-55 years. Conclusion The percentages of cell subsets differ between individuals from SSA compared to those elsewhere, perhaps reflecting a different antigenic milieu. These results serve as a reference for normal values in this population.
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Affiliation(s)
- Angela Nalwoga
- Department of Immunology and Microbiology, University of Colorado, Aurora, CO, United States
- Medical Research Council/ Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine, Entebbe, Uganda
| | - Marjorie Nakibuule
- Medical Research Council/ Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine, Entebbe, Uganda
| | - Romin Roshan
- Frederick National Laboratory for Cancer Research, Viral Oncology Section, AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick, MD, United States
| | - Moses Kwizera Mbonye
- Medical Research Council/ Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine, Entebbe, Uganda
| | - Wendell Miley
- Frederick National Laboratory for Cancer Research, Viral Oncology Section, AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick, MD, United States
| | - Denise Whitby
- Frederick National Laboratory for Cancer Research, Viral Oncology Section, AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick, MD, United States
| | - Robert Newton
- Medical Research Council/ Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine, Entebbe, Uganda
- Department of Health Sciences, University of York, York, United Kingdom
| | - Rosemary Rochford
- Department of Immunology and Microbiology, University of Colorado, Aurora, CO, United States
| | - Stephen Cose
- Medical Research Council/ Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine, Entebbe, Uganda
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Sadighi Akha AA, Csomós K, Ujházi B, Walter JE, Kumánovics A. Evolving Approach to Clinical Cytometry for Immunodeficiencies and Other Immune Disorders. Clin Lab Med 2023; 43:467-483. [PMID: 37481324 DOI: 10.1016/j.cll.2023.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2023]
Abstract
Primary immunodeficiencies were initially identified on the basis of recurrent, severe or unusual infections. Subsequently, it was noted that these diseases can also manifest with autoimmunity, autoinflammation, allergy, lymphoproliferation and malignancy, hence a conceptual change and their renaming as inborn errors of immunity. Ongoing advances in flow cytometry provide the opportunity to expand or modify the utility and scope of existing laboratory tests in this field to mirror this conceptual change. Here we have used the B cell subset, variably known as CD21low B cells, age-associated B cells and T-bet+ B cells, as an example to demonstrate this possibility.
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Affiliation(s)
- Amir A Sadighi Akha
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Krisztián Csomós
- Division of Pediatric Allergy/Immunology, University of South Florida, Johns Hopkins All Children's Hospital, St. Petersburg, FL, USA
| | - Boglárka Ujházi
- Division of Pediatric Allergy/Immunology, University of South Florida, Johns Hopkins All Children's Hospital, St. Petersburg, FL, USA
| | - Jolán E Walter
- Division of Pediatric Allergy/Immunology, University of South Florida, Johns Hopkins All Children's Hospital, St. Petersburg, FL, USA
| | - Attila Kumánovics
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
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Methods and Advances in the Design, Testing and Development of In Vitro Diagnostic Instruments. Processes (Basel) 2023. [DOI: 10.3390/pr11020403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
With the continuous improvement of medical testing and instrumentation engineering technologies, the design, testing and development methods of in vitro diagnostic instruments are developing rapidly. In vitro diagnostic instruments are also gradually developing into a class of typical high-end medical equipment. The design of in vitro diagnostic instruments involves a variety of medical diagnostic methods and biochemical, physical and other related technologies, and its development process involves complex system engineering. This paper systematically organizes and summarizes the design, testing and development methods of in vitro diagnostic instruments and their development in recent years, focusing on summarizing the related technologies and core aspects of the R&D process, and analyzes the development trend of the in vitro diagnostic instrument market.
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