Tumournecrosis factor insynovial exudates

SUMMARY Theactions oftumournecrosis factor (TNF)include resorption ofboneandcartilage, suggesting apotential role inthepathogenesis ofarthritis. TNFactivity waslooked forinsynovial fluids from137patients withdifferent rheumatic diseases. Unfractionated samples were tested in theL929bioassay. Significant TNFactivity that was neutralised bymonoclonal antibody toTNF alpha occurred in13(30%)of44samples. Raised TNF levels were notassociated with any particular disease typeorroutine laboratory markers ofinflammation butwere related todisease duration inosteoarthritis. Thefinding ofbiologically active TNFinsymptomatic joints ofarthritic patients supports theideathatitmay contribute tothepathogenesis ofjoint damageinchronic rheumatic diseases. Keyword:arthritis.