Figure 1.

Synovial histology in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and nonpsoriatic spondyloarthropathy (ankylosing spondylitis [AS] + undifferentiated spondyloarthropathy [USpA]). Synovial biopsies from RA, PsA and spondyloarthropathy (SpA; AS/USpA) patients were scored on a semiquantitative scale (0–3) by two independent observers. Representative sections of RA and PsA and nonpsoriatic SpA synovium are shown, and the corresponding semiquantitative score for each picture is indicated. The evaluated parameters included synovial lining layer thickness, CD83⁺ dendritic cells, CD38⁺ plasma cells, degree of vascularity, number of neutrophils (polymorphnuclear neutrophils [pmn]) and CD163⁺ macrophages.