TNF and synovitis: Building on this insight, Filer et al. recently demonstrated that an immune-protective effect exerted by TNF-exposed synovial fibroblasts from recent-onset arthritis patients in whom synovitis spontaneously resolves – whereby lymphocyte adhesion to endothelial cells in co-culture is prevented – was lost amongst synovial fibroblasts derived instead from patients with recent-onset rheumatoid arthritis, in whom synovitis persists [30▪▪].