Increased levels of soluble tumor necrosis factor receptors in the sera and synovial fluid of patients with rheumatic diseases. - Cope, A; Aderka, D; Doherty, M; Engelmann, H; Gibbons, D; Jones, A; Brennan, F; Maini, R; Wallach, D; Feldmann, M (Arthritis and rheumatism, 1992)