Session Information
Date: Monday, November 14, 2022
Title: Abstracts: B Cell Biology and Targets in Autoimmune and Inflammatory Disease
Session Type: Abstract Session
Session Time: 9:00AM-10:00AM
Background/Purpose: Ectopic lymphoid structures can develop in rheumatoid arthritis (RA) synovial tissue, but the precise pathways of B cell activation and selection are not well understood. Here, we use single cell RNA-sequencing (scRNA-seq) to better understand B cell receptor (BCR) repertoire differences and relationships both across cellular subsets and between tissue compartments in RA.
Methods: We sorted B cells from synovial tissue biopsies (n = 12) and matched peripheral blood samples (n = 10) to obtain paired scRNA-seq and repertoire (BCR) information from captured cells. After filtering low-quality cells and performing an initial round of clustering, B cells were identified and characterized. Analysis of cluster-specific markers and reference mapping were utilized to define the cell subpopulations present. Paired BCR information for each cell was incorporated, and the overlap, diversity, and clonal expansion were calculated using the IGH CDR3 to define clonal families. We also analyzed somatic hypermutation (SHM) and immunoglobulin isotype usage.
Results: After applying QC, 27,869 B cells were captured across all samples with > 80% of B cells having BCR information. Clustering of B cells identified 10 populations including multiple naïve-like (varying in IgD expression), memory, activated (Nur77+), age-associated B cells (ABCs), plasmablast and plasma cells. We observed 5-20 fold synovial enrichment of activated B cells and plasma cells whereas naïve-like clusters are predominant in the blood. ABCs and Activated B cells in the synovium had 0.5-1.2 percentage point higher SHM compared to PBL (p< 0.002). In every subject, we observed substantial clonal expansion in both the synovium and peripheral blood, as well as clones shared between these tissues, though most clones tended to segregate by tissue source. Sub-populations had more expanded clones in the synovium than periphery. Naïve B cells exhibited fewer expanded clonotypes than non-naïve populations. There was clonal sharing across multiple sub-populations, including between IgG and IgA plasma cells, and ABCs with Activated, Plasma and Memory B cells.
Conclusion: Our data demonstrate the value of integrating gene expression and repertoire data for the study of B cell responses in RA synovial tissue and provide evidence of in situ selection. Together, our findings suggest in situ differentiation of selected B cell clones and trafficking of these expanded clones between blood, synovial, and mucosal tissues.
To cite this abstract in AMA style:
Wagner A, Meednu N, Dunlap G, Zhang F, Jonsson A, Wei K, Ben-artzi A, Forbess L, Geraldino-Pardilla L, Horowitz D, Hughes L, Mandelin A, Salomon-Escoto K, Tabechian D, DiCarlo E, Gravallese E, Boyce B, Ritchlin C, Lederer J, McGeachy M, Gregersen P, Utz P, Robinson W, Maecker H, James J, Guthridge J, Perlman H, Bathon J, Goodman S, Firestein G, Boyle D, Bridges, Jr. S, Deane K, Holers V, Moreland L, Filer A, Pitzalis C, Bykerk V, Donlin L, Raychaudhuri S, Brenner M, RA/Lupus A, Rao D, McDavid A, Anolik J. Single-cell Profiling of B Cell Repertoire and Gene Expression in the RA Synovium Reveals Tissue Specific Clonal Expansion [abstract]. Arthritis Rheumatol. 2022; 74 (suppl 9). https://acrabstracts.org/abstract/single-cell-profiling-of-b-cell-repertoire-and-gene-expression-in-the-ra-synovium-reveals-tissue-specific-clonal-expansion/. Accessed .« Back to ACR Convergence 2022
ACR Meeting Abstracts - https://acrabstracts.org/abstract/single-cell-profiling-of-b-cell-repertoire-and-gene-expression-in-the-ra-synovium-reveals-tissue-specific-clonal-expansion/