Work

B Cell Receptor Repertoire Analysis of the CD21 lo B Cell Compartment in Healthy Individuals, Patients With Sjögren's Disease, and Patients With Radiographic Axial Spondyloarthritis

Year: 2024

Type: article

Abstract: ABSTRACT B cells with low or absent expression of CD21 (CD21 lo B cells) gained attention due to their expansion in the peripheral blood of patients with immune‐mediated, rheumatic diseases. This is not only observed in typical autoimmune diseases like systemic lupus erythematosus and Sjögren's disease (SjD) but also in radiographic axial spondyloarthritis (r‐axSpA), which is considered an autoinflammatory disease. To gain more insight into the origins of the heterogeneous CD21 lo B‐cell population, and its relation to the plasmablast (PB) compartment, we profiled the B‐cell‐receptor (BCR) repertoire in CD27 − and CD27 + fractions of CD21 lo B cells and early PBs using next‐generation sequencing. Populations were sorted from peripheral blood of healthy individuals, SjD patients, and r‐axSpA patients ( n = 10 for each group). In healthy individuals and both patient groups, our findings indicate that CD27 − CD21 lo B cells, which exhibit few mutations in their BCR, may develop into CD27 + CD21 lo B cells and PBs, both marked by considerably more mutations. Given the known expansion of circulating CD27 − CD21 lo B cells in SjD and r‐axSpA patients and clonal relationships with both CD27 + CD21 lo B cells and early PBs, these cells might actively contribute to (pathological) immune responses in rheumatic diseases with autoimmune and/or autoinflammatory characteristics.

Source: European Journal of Immunology

DOI: 10.1002/eji.202451398