Key clinical point: Synovial and serum B-lymphocyte involvement differ between autoantibody-positive and autoantibody-negative rheumatoid arthritis (RA), with autoantibody-negative RA closely resembling that in polyarticular psoriatic arthritis (PsA).
Major finding: The CD20+ B-cell aggregational score was significantly lower in autoantibody-negative RA than in autoantibody-positive RA (mean 1.8 vs 2.4; P = .03) but comparable to that of polyarticular PsA ( P = .78). The frequency of lympho-myeloid synovitis was lower in autoantibody-negative RA than in autoantibody-positive RA (38.2% vs 62.9%; P = .07) but comparable to that of polyarticular PsA ( P = .8).
Study details: This study included 131 patients who underwent synovial biopsy and were categorized into those having autoantibody-positive RA (n = 43), autoantibody-negative RA (n = 35), symmetric polyarticular PsA (n = 25), and asymmetric oligoarticular PsA (n = 28).
Disclosures: This study was supported by IRCCS Policlinico San Matteo Foundation, Pavia, Italy. C Montecucco and S Bugatti reported receiving grants or research support and personal fees from various sources. The remaining authors declared no conflicts of interest.
Source: De Stefano L et al. Synovial and serum B-cell signature of autoantibody-negative rheumatoid arthritis versus autoantibody-positive rheumatoid arthritis and psoriatic arthritis. Rheumatology (Oxford). 2023 (Jul 22). doi: 10.1093/rheumatology/kead378