Abstract: TH-PO0657
Autoantigen-Specific B Cells in Myeloperoxidase (MPO)-ANCA-Associated Vasculitis
Session Information
- Glomerular Diseases: Immunopathogenesis and Targeted Therapeutics
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Chen, Dhruti P., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Moon, Young-Hyun, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Gomez-Martinez, Ismael, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Woodcock, Mark G, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Taylor, Justin J., University of Virginia, Charlottesville, Virginia, United States
- Falk, Ronald, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Bunch, Donna O., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
Background
Therapies targeting B cells are effective in ANCA vasculitis. Autoantigen-specific ANCA producing B cells are a small but key subset though correlation with clinical activity is unknown. We hypothesize that these cells are present in active disease and repopulate in long term remission off therapy (LTROT) but other protective mediators maintain LTROT. We examined B regulatory cells in LTROT and B cell receptor (BCR) profiles of autoantigen-specific B cells.
Methods
Cryopreserved peripheral blood mononuclear cells (PMBCs) were immunophenotyped via flow cytometry. We identified autoantigen-specific B cells with biotinylated autoantigens or highly specific fluorescent tetramers loaded with MPO. Empty tetramer backbone was used to exclude non-specifically binding cells. PBMCs incubated with tetramers and enriched for fluorophore-binding cells were sorted for tetramer positive anti-MPO B cells (Tpos). Controls included MPO-tetramer negative cells (Tneg) and B cells recovered from residual fluorophore-negative cells (Aneg). Cells were expanded in vitro with antigen stimulation prior to RNA isolation for bulk BCR sequencing. MPO-ANCA in supernatant was tested by ELISA.
Results
We found increased B regulatory cell population in LTROT compared to active disease (Fig 1A). Autoantigen specific B cells are present in active disease and LTROT (Fig 1B). Patient anti-MPO B cells, but not from healthy controls, secrete anti-MPO IgG (Fig 2). Bulk BCR sequencing shows clonally expanded MPO-specific B cells and overlap in the complementarity determining region, CDR3 (higher Morosita-Horn overlap index) among patients only.
Conclusion
ANCA patients in LTROT have more B regulatory cells and repopulation of autoantigen specific B cells. Bulk BCR sequencing of anti MPO B cells from patients suggests CDR3 overlap. Single cell studies will provide data on detailed immunophenotypes and BCR clones in LTROT vs active disease.
Funding
- NIDDK Support