B Cells in Rheumatoid Arthritis: From Pathogenic Players to Disease Biomarkers
Figure 2
The gradient of B-cell infiltration and aggregation in rheumatoid synovitis. (a) Representative examples of progressive degrees of synovial B-cell infiltration in specimens from 4 independent patients with rheumatoid arthritis stained for the B-cell marker CD20 are shown. Original magnification: 100x. (b) Validity of the B-cell aggregational score is confirmed by parallel immunohistochemical and mRNA expression analysis for the B-cell marker CD19. ((c), (d)) The progressive enrichment in synovial B aggregates is coupled with progressively increasing levels of the B-cell chemoattractant CXCL13 (c) and the cytokine lymphotoxin (LT)-β (d), known to regulate lymphoid tissue ontogenesis and neogenesis. ((e)–(g)) B-cell aggregation is associated with the progressive increase in markers reflecting immune cell activation, such as the B-cell activation marker activation-induced cytidine deaminase (AID) (e) and the T cell-derived cytokines interferon (IFN)-γ (f) and interleukin (IL)-2 (g). The graphs show mean (SD) expression levels stratified according to the B-cell aggregational score.
