JCI Insight (Nov 2021)

Circulating autoreactive proteinase 3+ B cells and tolerance checkpoints in ANCA-associated vasculitis

  • Alvise Berti,
  • Sophie Hillion,
  • Amber M. Hummel,
  • Young Min Son,
  • Nedra Chriti,
  • Tobias Peikert,
  • Eva M. Carmona,
  • Wayel H. Abdulahad,
  • Peter Heeringa,
  • Kristina M. Harris,
  • E. William St. Clair,
  • Paul Brunetta,
  • Fernando C. Fervenza,
  • Carol A. Langford,
  • Cees G.M. Kallenberg,
  • Peter A. Merkel,
  • Paul A. Monach,
  • Philip Seo,
  • Robert F. Spiera,
  • John H. Stone,
  • Guido Grandi,
  • Jie Sun,
  • Jacques-Olivier Pers,
  • Ulrich Specks,
  • Divi Cornec,
  • for the RAVE-ITN Research Group

Journal volume & issue
Vol. 6, no. 22

Abstract

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BACKGROUND Little is known about the autoreactive B cells in antineutrophil cytoplasmic antibody–associated (ANCA-associated) vasculitis (AAV). We aimed to investigate tolerance checkpoints of circulating antigen-specific proteinase 3–reactive (PR3+) B cells.METHODS Multicolor flow cytometry in combination with bioinformatics and functional in vitro studies were performed on baseline samples of PBMCs from 154 well-characterized participants of the RAVE trial (NCT00104299) with severely active PR3-AAV and myeloperoxidase-AAV (MPO-AAV) and 27 healthy controls (HCs). Clinical data and outcomes from the trial were correlated with PR3+ B cells (total and subsets).RESULTS The frequency of PR3+ B cells among circulating B cells was higher in participants with PR3-AAV (4.77% median [IQR, 3.98%–6.01%]) than in participants with MPO-AAV (3.16% median [IQR, 2.51%–5.22%]) and participants with AAV compared with HCs (1.67% median [IQR, 1.27%–2.16%], P < 0.001 for all comparisons), implying a defective central tolerance checkpoint in patients with AAV. Only PBMCs from participants with PR3-AAV contained PR3+ B cells capable of secreting PR3-ANCA IgG in vitro, proving they were functionally distinct from those of participants with MPO-AAV and HCs. Unsupervised clustering identified subtle subsets of atypical autoreactive PR3+ memory B cells accumulating through the maturation process in patients with PR3-AAV. PR3+ B cells were enriched in the memory B cell compartment of participants with PR3-AAV and were associated with higher serum CXCL13 levels, suggesting an increased germinal center activity. PR3+ B cells correlated with systemic inflammation (C-reactive protein and erythrocyte sedimentation rate, P < 0.05) and complete remission (P < 0.001).CONCLUSION This study suggests the presence of defective central antigen-independent and peripheral antigen-dependent checkpoints in patients with PR3-AAV, elucidating the selection process of autoreactive B cells.Trial registration ClinicalTrials.gov NCT00104299.Funding The Vasculitis Foundation, the National Institute of Allergy and Infectious Diseases of the NIH, and the Mayo Foundation for Education and Research.

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