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Prskalo L, Skopnik CM, Goerlich N, Freund P, Wagner L, Grothgar E, Mirkheshti P, Klocke J, Sonnemann J, Metzke D, Schneider U, Hiepe F, Eckardt KU, Salama AD, Bieringer M, Schreiber A, Enghard P. Urinary CD4 + T Cells Predict Renal Relapse in ANCA-Associated Vasculitis. J Am Soc Nephrol 2024; 35:483-494. [PMID: 38231590 PMCID: PMC11000730 DOI: 10.1681/asn.0000000000000311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 01/04/2024] [Indexed: 01/18/2024] Open
Abstract
SIGNIFICANCE STATEMENT Early identification of patients at risk of renal flares in ANCA vasculitis is crucial. However, current clinical parameters have limitations in predicting renal relapse accurately. This study investigated the use of urinary CD4 + T lymphocytes as a predictive biomarker for renal flares in ANCA vasculitis. This study, including urine samples from 102 patients, found that the presence of urinary CD4 + T cells was a robust predictor of renal relapse within a 6-month time frame, with a sensitivity of 60% and a specificity of 97.8%. The diagnostic accuracy of urinary CD4 + T cells exceeded that of ANCA titers, proteinuria, and hematuria. Monitoring urinary CD4 + T lymphocytes could help assess the risk of future renal relapse, enabling early preventive measures and tailored treatment strategies. BACKGROUND In ANCA-associated vasculitis, there is a lack of biomarkers for predicting renal relapse. Urinary T cells have been shown to differentiate active GN from remission in ANCA-associated vasculitis, but their predictive value for renal flares remains unknown. METHODS The PRE-FLARED study was a prospective multicenter biomarker study including 102 individuals with ANCA-associated vasculitis in remission aimed to predict renal relapse by quantifying urinary CD4 + T-cell subsets using flow cytometry at baseline and monitoring clinical outcomes over a 6-month follow-up. RESULTS Among the participants, ten experienced renal relapses, two had non-renal flares, and 90 remained in stable remission. The median baseline urinary CD4 + T-cell count was significantly higher in patients who relapsed compared with those in remission. Receiver operating characteristic curve analysis of urinary CD4 + T-cell counts showed an area under the curve value of 0.88 for predicting renal flares, outperforming ANCA titers, hematuria, and proteinuria. Using a cutoff of 490 CD4 + T cells per 100 ml urine, the sensitivity and specificity in identifying patients with future renal flares were 60% and 97.8%, respectively. In a post hoc analysis, combining urinary CD4 + T-cell counts with proteinase-3 ANCA levels suggested improved predictive performance in the PR3 + subgroup. In addition, the number of urinary CD4 + T cells showed a limited correlation with a decline in GFR and an increase in proteinuria over the follow-up period. CONCLUSIONS This study concluded that urinary CD4 + T-cell counts could identify patients with ANCA-associated vasculitis at a substantial risk of renal relapse within 6 months. Combining these counts with ANCA levels further improved the prediction of relapse. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER Urinary T Lymphocytes Predict Renal Flares in Patients With Inactive ANCA-associated Glomerulonephritis (PRE-FLARED), NCT04428398 .
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Affiliation(s)
- Luka Prskalo
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Christopher M. Skopnik
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Nina Goerlich
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Paul Freund
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Leonie Wagner
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Emil Grothgar
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Pouneh Mirkheshti
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jan Klocke
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Janis Sonnemann
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Diana Metzke
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Udo Schneider
- Department of Rheumatology and Clinical Immunology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Falk Hiepe
- Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
- Department of Rheumatology and Clinical Immunology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Kai-Uwe Eckardt
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Alan D. Salama
- University College London Department of Renal Medicine, Royal Free Hospital, London, United Kingdom
| | - Markus Bieringer
- Department of Nephrology, Helios Klinikum Berlin-Buch, Berlin, Germany
| | - Adrian Schreiber
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Philipp Enghard
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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2
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Freund P, Skopnik CM, Metzke D, Goerlich N, Klocke J, Grothgar E, Prskalo L, Hiepe F, Enghard P. Addition of formaldehyde releaser imidazolidinyl urea and MOPS buffer to urine samples enables delayed processing for flow cytometric analysis of urinary cells: A simple, two step conservation method of urinary cells for flow cytometry. Cytometry B Clin Cytom 2023; 104:417-425. [PMID: 36880455 DOI: 10.1002/cyto.b.22117] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 02/03/2023] [Accepted: 02/13/2023] [Indexed: 03/08/2023]
Abstract
INTRODUCTION Kidney diseases are a major health concern worldwide. Currently there is a large unmet need for novel biomarkers to non-invasively diagnose and monitor kidney diseases. Urinary cells are promising biomarkers and their analysis by flow cytometry has demonstrated its utility in diverse clinical settings. However, up to date this methodology depends on fresh samples, as cellular event counts and the signal-to-noise-ratio deter over time. Here we developed an easy-to-use two-step preservation method for conservation of urine samples for subsequent flow cytometry. METHODS The protocol utilizes a combination of the formaldehyde releasing agent imidazolidinyl urea (IU) and MOPS buffer, leading to gentle fixation of urinary cells. RESULTS The preservation method increases acceptable storing time of urine samples from several hours to up to 6 days. Cellular event counts and staining properties of cells remain comparable to fresh untreated samples. OUTLOOK The hereby presented preservation method facilitates future investigations on flow cytometry of urinary cells as potential biomarkers and may enable broad implementation in clinical practice.
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Affiliation(s)
- Paul Freund
- Department of Nephrology and Medical Intensive Care, Charité - Universital Hospital Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
| | - Christopher M Skopnik
- Department of Nephrology and Medical Intensive Care, Charité - Universital Hospital Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
| | - Diana Metzke
- Department of Nephrology and Medical Intensive Care, Charité - Universital Hospital Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
| | - Nina Goerlich
- Department of Nephrology and Medical Intensive Care, Charité - Universital Hospital Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
| | - Jan Klocke
- Department of Nephrology and Medical Intensive Care, Charité - Universital Hospital Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
| | - Emil Grothgar
- Department of Nephrology and Medical Intensive Care, Charité - Universital Hospital Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
| | - Luka Prskalo
- Department of Nephrology and Medical Intensive Care, Charité - Universital Hospital Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
| | - Falk Hiepe
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
- Department of Rheumatology and Clinical Immunology, Charite - Universital Hospital Berlin, Berlin, Germany
| | - Philipp Enghard
- Department of Nephrology and Medical Intensive Care, Charité - Universital Hospital Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), An Institute of the Leibniz Foundation, Berlin, Germany
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3
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Kubagawa H, Clark C, Skopnik CM, Mahmoudi Aliabadi P, Al-Qaisi K, Teuber R, Jani PK, Radbruch A, Melchers F, Engels N, Wienands J. Physiological and Pathophysiological Roles of IgM Fc Receptor (FcµR) Isoforms. Int J Mol Sci 2023; 24:ijms24065728. [PMID: 36982860 PMCID: PMC10058298 DOI: 10.3390/ijms24065728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/14/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
IgM is the first antibody to emerge during phylogeny, ontogeny, and immune responses and serves as a first line of defense. Effector proteins interacting with the Fc portion of IgM, such as complement and its receptors, have been extensively studied for their functions. IgM Fc receptor (FcµR), identified in 2009, is the newest member of the FcR family and is intriguingly expressed by lymphocytes only, suggesting the existence of distinct functions as compared to the FcRs for switched Ig isotypes, which are expressed by various immune and non-hematopoietic cells as central mediators of antibody-triggered responses by coupling the adaptive and innate immune responses. Results from FcµR-deficient mice suggest a regulatory function of FcµR in B cell tolerance, as evidenced by their propensity to produce autoantibodies of both IgM and IgG isotypes. In this article, we discuss conflicting views about the cellular distribution and potential functions of FcµR. The signaling function of the Ig-tail tyrosine-like motif in the FcµR cytoplasmic domain is now formally shown by substitutional experiments with the IgG2 B cell receptor. The potential adaptor protein associating with FcµR and the potential cleavage of its C-terminal cytoplasmic tail after IgM binding are still enigmatic. Critical amino acid residues in the Ig-like domain of FcµR for interacting with the IgM Cµ4 domain and the mode of interaction are now defined by crystallographic and cryo-electron microscopic analyses. Some discrepancies on these interactions are discussed. Finally, elevated levels of a soluble FcµR isoform in serum samples are described as the consequence of persistent B cell receptor stimulation, as seen in chronic lymphocytic leukemia and probably in antibody-mediated autoimmune disorders.
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Affiliation(s)
| | - Caren Clark
- Institute of Cellular & Molecular Immunology, University Medical Center, 37073 Göttingen, Germany
| | | | | | | | - Ruth Teuber
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany
| | - Peter K Jani
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany
| | | | - Fritz Melchers
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany
| | - Niklas Engels
- Institute of Cellular & Molecular Immunology, University Medical Center, 37073 Göttingen, Germany
| | - Jürgen Wienands
- Institute of Cellular & Molecular Immunology, University Medical Center, 37073 Göttingen, Germany
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4
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Klocke J, Kim SJ, Skopnik CM, Hinze C, Boltengagen A, Metzke D, Grothgar E, Prskalo L, Wagner L, Freund P, Görlich N, Muench F, Schmidt-Ott KM, Mashreghi MF, Kocks C, Eckardt KU, Rajewsky N, Enghard P. Urinary single-cell sequencing captures kidney injury and repair processes in human acute kidney injury. Kidney Int 2022; 102:1359-1370. [PMID: 36049643 DOI: 10.1016/j.kint.2022.07.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 07/06/2022] [Accepted: 07/27/2022] [Indexed: 01/12/2023]
Abstract
Acute kidney injury (AKI) is a major health issue, the outcome of which depends primarily on damage and reparative processes of tubular epithelial cells. Mechanisms underlying AKI remain incompletely understood, specific therapies are lacking and monitoring the course of AKI in clinical routine is confined to measuring urine output and plasma levels of filtration markers. Here we demonstrate feasibility and potential of a novel approach to assess the cellular and molecular dynamics of AKI by establishing a robust urine-to-single cell RNA sequencing (scRNAseq) pipeline for excreted kidney cells via flow cytometry sorting. We analyzed 42,608 single cell transcriptomes of 40 urine samples from 32 patients with AKI and compared our data with reference material from human AKI post-mortem biopsies and published mouse data. We demonstrate that tubular epithelial cells transcriptomes mirror kidney pathology and reflect distinct injury and repair processes, including oxidative stress, inflammation, and tissue rearrangement. We also describe an AKI-specific abundant urinary excretion of adaptive progenitor-like cells. Thus, single cell transcriptomics of kidney cells excreted in urine provides noninvasive, unprecedented insight into cellular processes underlying AKI, thereby opening novel opportunities for target identification, AKI sub-categorization, and monitoring of natural disease course and interventions.
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Affiliation(s)
- Jan Klocke
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany.
| | - Seung Joon Kim
- Systems Biology of Gene-Regulatory Elements, Berlin Institute for Medical Systems Biology (BIMSB), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Christopher M Skopnik
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Christian Hinze
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Molecular and Translational Kidney Research, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany; Department of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany
| | - Anastasiya Boltengagen
- Systems Biology of Gene-Regulatory Elements, Berlin Institute for Medical Systems Biology (BIMSB), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Diana Metzke
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Emil Grothgar
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Luka Prskalo
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Leonie Wagner
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Paul Freund
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Nina Görlich
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Frédéric Muench
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Kai M Schmidt-Ott
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Molecular and Translational Kidney Research, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany; Department of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany
| | - Mir-Farzin Mashreghi
- Therapeutic Gene Regulation, Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
| | - Christine Kocks
- Systems Biology of Gene-Regulatory Elements, Berlin Institute for Medical Systems Biology (BIMSB), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Kai-Uwe Eckardt
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Nikolaus Rajewsky
- Systems Biology of Gene-Regulatory Elements, Berlin Institute for Medical Systems Biology (BIMSB), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Philipp Enghard
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Deutsches Rheuma-Forschungszentrum, an Institute of the Leibniz Foundation, Berlin, Germany
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5
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Grothgar E, Goerlich N, Samans B, Skopnik CM, Metzke D, Klocke J, Prskalo L, Freund P, Wagner L, Duerr M, Matz M, Olek S, Budde K, Paliege A, Enghard P. Urinary CD8+HLA-DR+ T Cell Abundance Non-invasively Predicts Kidney Transplant Rejection. Front Med (Lausanne) 2022; 9:928516. [PMID: 35911418 PMCID: PMC9334669 DOI: 10.3389/fmed.2022.928516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/23/2022] [Indexed: 12/05/2022] Open
Abstract
Early detection of kidney transplant (KT) rejection remains a challenge in patient care. Non-invasive biomarkers hold high potential to detect rejection, adjust immunosuppression, and monitor KT patients. So far, no approach has fully satisfied requirements to innovate routine monitoring of KT patients. In this two-center study we analyzed a total of 380 urine samples. T cells and tubular epithelial cells were quantified in KT patients with graft deterioration using flow cytometry. Epigenetic urine cell quantification was used to confirm flow cytometric results. Moreover, a cohort of KT patients was followed up during the first year after transplantation, tracking cell subsets over time. Abundance of urinary cell counts differed in patients with and without rejection. Most strikingly, various T cell subsets were enriched in patients with T cell-mediated rejection (TCMR) compared to patients without TCMR. Among T cell subsets, CD8+HLA-DR+ T cells were most distinctive (AUC = 0.91, Spec.: 95.9%, Sens.: 76.5%). Epigenetic analysis confirmed T cell and tubular epithelial cell quantities as determined by flow cytometry. Urinary T cell abundance in new KT patients decreased during their first year after transplantation. In conclusion urinary T cells reflect intrarenal inflammation in TCMR. T cell subsets yield high potential to monitor KT patients and detect rejection. Hereby we present a promising biomarker to non-invasively diagnose TCMR.
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Affiliation(s)
- Emil Grothgar
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
- *Correspondence: Emil Grothgar
| | - Nina Goerlich
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
- Berlin Institute of Health (BIH) at Charité–Universitätsmedizin Berlin, Berlin, Germany
- Nina Goerlich
| | - Bjoern Samans
- Ivana Türbachova Laboratory for Epigenetics, Precision for Medicine GmbH, Berlin, Germany
| | - Christopher M. Skopnik
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
| | - Diana Metzke
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
| | - Jan Klocke
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
| | - Luka Prskalo
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
| | - Paul Freund
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
| | - Leonie Wagner
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
| | - Michael Duerr
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Mareen Matz
- Berlin Institute of Health (BIH) at Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Sven Olek
- Ivana Türbachova Laboratory for Epigenetics, Precision for Medicine GmbH, Berlin, Germany
| | - Klemens Budde
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Philipp Enghard
- Department of Nephrology and Intensive Care, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Rheumatism Research Center Berlin (DRFZ), Berlin, Germany
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Skopnik CM, Riedel R, Addo RK, Heinz GA, Heinrich F, Honjo K, Durek P, Enghard P, Mashreghi MF, Radbruch A, Kubagawa H. Questioning whether IgM Fc receptor (FcµR) is expressed by innate immune cells. Nat Commun 2022; 13:3951. [PMID: 35817797 PMCID: PMC9273587 DOI: 10.1038/s41467-022-29407-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/17/2022] [Indexed: 11/24/2022] Open
Affiliation(s)
| | - René Riedel
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Richard K Addo
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Gitta Anne Heinz
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Frederik Heinrich
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Kazuhito Honjo
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35209, USA
| | - Pawel Durek
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Philipp Enghard
- Department of Nephrology and Medical Intensive Care, Charité-Universitätmedizin, 10117, Berlin, Germany
| | | | - Andreas Radbruch
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Hiromi Kubagawa
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany.
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7
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Kubagawa H, Skopnik CM, Al-Qaisi K, Calvert RA, Honjo K, Kubagawa Y, Teuber R, Aliabadi PM, Enghard P, Radbruch A, Sutton BJ. Differences between Human and Mouse IgM Fc Receptor (FcµR). Int J Mol Sci 2021; 22:ijms22137024. [PMID: 34209905 PMCID: PMC8267714 DOI: 10.3390/ijms22137024] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/23/2021] [Accepted: 06/25/2021] [Indexed: 01/02/2023] Open
Abstract
Both non-immune "natural" and antigen-induced "immune" IgM are important for protection against pathogens and for regulation of immune responses to self-antigens. Since the bona fide IgM Fc receptor (FcµR) was identified in humans by a functional cloning strategy in 2009, the roles of FcµR in these IgM effector functions have begun to be explored. In this short essay, we describe the differences between human and mouse FcµRs in terms of their identification processes, cellular distributions and ligand binding activities with emphasis on our recent findings from the mutational analysis of human FcµR. We have identified at least three sites of human FcµR, i.e., Asn66 in the CDR2, Lys79 to Arg83 in the DE loop and Asn109 in the CDR3, responsible for its constitutive IgM-ligand binding. Results of computational structural modeling analysis are consistent with these mutational data and a model of the ligand binding, Ig-like domain of human FcµR is proposed. Serendipitously, substitution of Glu41 and Met42 in the CDR1 of human FcµR with mouse equivalents Gln and Leu, either single or more prominently in combination, enhances both the receptor expression and IgM binding. These findings would help in the future development of preventive and therapeutic interventions targeting FcµR.
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Affiliation(s)
- Hiromi Kubagawa
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany; (C.M.S.); (K.A.-Q.); (R.T.); (P.M.A.); (A.R.)
- Correspondence: ; Tel.: +49-030-2846-0782
| | - Christopher M. Skopnik
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany; (C.M.S.); (K.A.-Q.); (R.T.); (P.M.A.); (A.R.)
| | - Khlowd Al-Qaisi
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany; (C.M.S.); (K.A.-Q.); (R.T.); (P.M.A.); (A.R.)
| | - Rosaleen A. Calvert
- Randall Centre for Cell and Molecular Biophysics, King’s College, London SE1 1UL, UK; (R.A.C.); (B.J.S.)
| | - Kazuhito Honjo
- Department of Pathology of University of Alabama at Birmingham, Birmingham, AL 35294, USA.; (K.H.); (Y.K.)
| | - Yoshiki Kubagawa
- Department of Pathology of University of Alabama at Birmingham, Birmingham, AL 35294, USA.; (K.H.); (Y.K.)
| | - Ruth Teuber
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany; (C.M.S.); (K.A.-Q.); (R.T.); (P.M.A.); (A.R.)
| | - Pedram Mahmoudi Aliabadi
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany; (C.M.S.); (K.A.-Q.); (R.T.); (P.M.A.); (A.R.)
| | - Philipp Enghard
- Department of Nephrology and Medical Intensive Care, Charité-Universitätmedizin, 10117 Berlin, Germany;
| | - Andreas Radbruch
- Deutsches Rheuma-Forschungszentrum, 10117 Berlin, Germany; (C.M.S.); (K.A.-Q.); (R.T.); (P.M.A.); (A.R.)
| | - Brian J. Sutton
- Randall Centre for Cell and Molecular Biophysics, King’s College, London SE1 1UL, UK; (R.A.C.); (B.J.S.)
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Skopnik CM, Al-Qaisi K, Calvert RA, Enghard P, Radbruch A, Sutton BJ, Kubagawa H. Identification of Amino Acid Residues in Human IgM Fc Receptor (FcµR) Critical for IgM Binding. Front Immunol 2021; 11:618327. [PMID: 33584711 PMCID: PMC7873564 DOI: 10.3389/fimmu.2020.618327] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/03/2020] [Indexed: 11/17/2022] Open
Abstract
Both non-immune “natural” and antigen-induced “immune” IgM are important for protection against infections and for regulation of immune responses to self-antigens. The roles of its Fc receptor (FcµR) in these IgM effector functions have begun to be explored. In the present study, by taking advantage of the difference in IgM-ligand binding of FcµRs of human (constitutive binding) and mouse (transient binding), we replaced non-conserved amino acid residues of human FcµR with mouse equivalents before establishment of cell lines stably expressing mutant or wild-type (WT) receptors. The resultant eight-different mutant FcµR-bearing cells were compared with WT receptor-bearing cells for cell-surface expression and IgM-binding by flow cytometric assessments using receptor-specific mAbs and IgM paraproteins as ligands. Three sites Asn66, Lys79-Arg83, and Asn109, which are likely in the CDR2, DE loop and CDR3 of the human FcµR Ig-like domain, respectively, were responsible for constitutive IgM binding. Intriguingly, substitution of Glu41 and Met42 in the presumed CDR1 with the corresponding mouse residues Gln and Leu, either single or more prominently in combination, enhanced both the receptor expression and IgM binding. A four-aa stretch of Lys24-Gly27 in the predicted A ß-strand of human FcµR appeared to be essential for maintenance of its proper receptor conformation on plasma membranes because of reduction of both receptor expression and IgM-binding potential when these were mutated. Results from a computational structural modeling analysis were consistent with these mutational data and identified a possible mode of binding of FcµR with IgM involving the loops including Asn66, Arg83 and Asn109 of FcµR interacting principally with the Cµ4 domain including Gln510 and to a lesser extent Cµ3 domain including Glu398, of human IgM. To our knowledge, this is the first experimental report describing the identification of amino acid residues of human FcµR critical for binding to IgM Fc.
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Affiliation(s)
| | - Khlowd Al-Qaisi
- Humoral Immune Regulation, Deutsches Rheuma-Forschungszentrum, Berlin, Germany
| | - Rosaleen A Calvert
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Philipp Enghard
- Department of Nephrology and Medical Intensive Care, Charité-Universitätmedizin, Berlin, Germany
| | - Andreas Radbruch
- Humoral Immune Regulation, Deutsches Rheuma-Forschungszentrum, Berlin, Germany
| | - Brian J Sutton
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Hiromi Kubagawa
- Humoral Immune Regulation, Deutsches Rheuma-Forschungszentrum, Berlin, Germany
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Kubagawa H, Skopnik CM, Zimmermann J, Durek P, Chang HD, Yoo E, Bertoli LF, Honjo K, Radbruch A. Authentic IgM Fc Receptor (FcμR). Curr Top Microbiol Immunol 2017; 408:25-45. [PMID: 28702710 DOI: 10.1007/82_2017_23] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Since the bona fide Fc receptor for IgM antibody (FcµR) was identified eight years ago, much progress has been made in defining its biochemical nature, cellular distribution, and effector function. However, there are clearly conflicting results, especially about the cellular distribution and function of murine FcµR. In this short article, we will discuss recent findings from us and other investigators along with our interpretations and comments that may help to resolve the existing puzzles and should open new avenues of investigation.
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Affiliation(s)
- Hiromi Kubagawa
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany.
| | | | - Jakob Zimmermann
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Pawel Durek
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Hyun-Dong Chang
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Esther Yoo
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
| | | | - Kazuhito Honjo
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35209, USA
| | - Andreas Radbruch
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
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