A6.20 Ectopic lymphoid neogenesis is strongly associated with activation of the IL-23 pathway in rheumatoid synovitis

Background and objectives The functional relevance of synovial ectopic lymphoid neogenesis (ELN) in rheumatoid arthritis (RA) remains unknown. As ELN correlates with the degree of tissue inflammation we investigated whether ELN was associated with specific cytokine profiles. Materials and methods Paired synovial tissue (ST) (n = 63) and fluid (SF) (n = 44) was obtained from the inflamed knee joints of RA patients. Synovial inflammation and ELN was determined by immunohistology. CD21L was used as molecular marker of ELN. Cytokine expression was determined by ELISA and quantitative PCR in SF and ST, respectively. Results 48% of ST displayed ELN by histology. ELN+ samples had increased T and B lymphocyte infiltration (p Conclusion Synovial ELN in RA is strongly associated with increased expression of IL-23/IL-17-related cytokines. Whether patients depicting synovial ELN respond differently to therapeutic targeting of this pathway remains to be determined.