TIC Publications
Our thought provoking publications highlight our progress and our commitment to discoveries and innovations that will lead to a better understanding of the mechanism of allograft rejection.
Featured articles:
Identification of Antibodies to DQβ:DRα Interisotypic Heterodimers in Human Sera
Thoa Nong, BS, Nengjen Remi Shih, PhD, Robert A. Bray, PhD, Mayra Lopez-Cepero, PhD,
Cathi Murphey, PhD, Peter W. Nickerson, MD, and Jar-How Lee, PhD
Abstract
Background
HLA class II antigens, DR, DQ, and DP, comprised an α and β chains, which typically combine, within
the same isotype, to form the major histocompatibility complex:peptide complex. Interisotypic pairing is not commonly
observed. Although reports of DQβ:DRα heterodimers exist, the pairing was reported to be unstable and, therefore, not studied to any extent.
Methods
DQβ:DRα single antigens were produced through transfectant cell lines and used to identify
and characterize positive reactive human sera by a multiplex bead-based assay.
Results
Stable DQβ:DRα transfectants were constructed. Cell surface staining with class II–specific monoclonal antibodies revealed that some DQB1 alleles appear to be more efficient in expressing DQβ:DRα heterodimers. Interestingly, alleles within the same serological group varied in their efficiency of forming dimers on the cell surface. For example, DQβ0601:DRα had the highest transfection and cell membrane expression efficiency among 16 common DQB1 alleles tested. In contrast, DQβ0603:DRα-positive transfectants demonstrated minimal surface expression. Assembly of DQβ0601:DRα was not affected by the presence of a DQα chain. DQβ0601:DRα and DQβ0603:DRα single-antigen beads were used to screen human sera. Positive sera were identified that reacted to the unique epitopes of DQβ0601:DRα protein on the cell surface of the transfectants.
Conclusions
Our studies have demonstrated that unique DQβ:DRα heterodimers can be formed and are stably expressed on the cell surface. Such antigenic combinations, presented on single-antigen beads, demonstrated that patient sera can react with such heterodimers. Investigations on the potential clinical roles of antibodies against such interisotypic heterodimers are now possible.
(Transplantation 2024;00: 00–00).
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Understanding and measuring human B-cell tolerance and its breakdown in autoimmune disease
Kevin S Cashman , Scott A Jenks. , Matthew C Woodruff , Deepak Tomar , Christopher M Tipton , Christopher D Scharer ,
F Eun-Hyung Lee , Jeremy M Boss , Iñaki Sanz
Author information
1. Department of Medicine, Division of Rheumatology, Emory University, Atlanta, GA, USA
2. Lowance Center for Human Immunology, Emory University, Atlanta, GA, USA
3. Department of Microbiology and Immunology, School of Medicine, Emory University, Atlanta, GA, USA
4. Department of Medicine, Division of Pulmonary, Allergy and Critical Care, Emory University, Atlanta, GA, USA
Abstract
INTRODUCTION:
The maintenance of immunological tolerance of B lymphocytes is a complex and critical process that must be implemented as to avoid the detrimental development of autoreactivity and possible autoimmunity. Murine models have been invaluable to elucidate many of the key components in B-cell tolerance; however, translation to human homeostatic and pathogenic immune states can be difficult to assess. Functional autoreactive, flow cytometric, and single-cell cloning assays have proven to be critical in deciphering breaks in B-cell tolerance within autoimmunity; however, newer approaches to assess human B-cell tolerance may prove to be vital in the further exploration of underlying tolerance defects. In this review, we supply a comprehensive overview of human immune tolerance checkpoints with associated mechanisms of enforcement, and highlight current and future methodologies which are likely to benefit future studies into the mechanisms that become defective in human autoimmune conditions.
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Journal
Cashman KS, Jenks SA, Woodruff MC, et al. Understanding and measuring human B-cell tolerance and its breakdown in autoimmune disease. Immunol Rev. 2019;292:76–89. https ://doi.org/10.1111/imr.12820
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Donor-specific B Cell Memory in Alloimmunized Kidney Transplant Recipients: First Clinical Application of a Novel Method
Caroline Wehmeier , Gonca E Karahan , Juliette Krop , Yvonne de Vaal , Janneke Langerak-Langerak , Isabelle Binet ,
Stefan Schaub , Dave L Roelen , Frans H J Claas , Sebastiaan Heidt , Swiss Transplant Cohort Study
Author information
1. Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands.
2. Department of Nephrology and Transplantation Medicine, Kantonsspital St. Gallen, St. Gallen, Switzerland.
3. Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
Abstract
Background
HLA-specific memory B cells may contribute to the serum HLA antibody pool upon antigen reexposure. The aim of this pilot study was to investigate the presence of concurrent donor-specific memory B cell-derived HLA antibodies (DSA-M) in renal allograft recipients with pretransplant donor-specific HLA antibodies (DSA) and its association with occurrence of antibody-mediated rejection (AMR) using a recently developed method.
Methods
Twenty patients with Luminex single antigen bead (SAB) assay-defined DSA but negative complement-dependent cytotoxicity crossmatches were enrolled. Plasma samples and peripheral blood mononuclear cells were collected at 3 timepoints (pretransplant, mo 6, mo 12). We analyzed IgG-purified and concentrated culture supernatants from polyclonally activated peripheral blood mononuclear cells using SAB assays and compared HLA antibody profiles with same day plasma results.
Results
Plasma SAB analysis revealed 35 DSA in 20 patients pretransplant. DSA-M were detected in 9 of 20 (45%) patients and for 10 of 35 specificities (29%). While median mean fluorescence intensity values of DSA with concurrent DSA-M (5877) were higher than those of DSA without DSA-M (1476), 3 of 6 patients with AMR and low mean fluorescence intensity DSA (<3000) had DSA-M. Overall, pretransplant DSA/DSA-Mpos allograft recipients showed a higher incidence of biopsy-proven (sub)clinical AMR (P = 0.032) and a higher extent (g≥1 + ptc≥1) of microvascular inflammation (67% vs 9%, P = 0.02). In 17 patients (28 DSA) with posttransplant analyses, persisting DSA posttransplant had more often DSA-M (6/12; 50%) than nonpersisting DSA (2/16; 13%).
Conclusions
Assessment of DSA-M might be a novel tool to supplement serum HLA antibody analysis for pretransplant risk stratification in patients with DSA.
Journal:
Wehmeier C, Karahan G, Krop J, et al. Donor-specific B Cell Memory in Alloimmunized Kidney Transplant Recipients: First Clinical Application of a Novel Method. Transplantation​. 2020 May;104(5):1026-1032.doi: 10.1097/TP.0000000000002909.