title: Interleukin-6 (IL-6) in synovial fluid and serum of patients with rheumatic diseases.
abstract: Interleukin-6 (IL-6) is a monokine with a number of biological activities, which are intimately related to inflammatory responses. We have measured IL-6 levels in synovial fluid (SF) and serum (Se) of patients with rheumatic diseases. SF-IL-6 levels were a thousand-fold higher than corresponding Se levels and a positive correlation was found between SF and Se levels suggesting that Se-IL-6 is derived from IL-6 produced in the joint. Se levels of IL-6 were also positively correlated to C-reactive protein (CRP) levels, supporting the in vitro experiments showing that IL-6 stimulates hepatocytes to produce CRP. Finally we observed a positive correlation between SF-IL-6 levels and the local activity score.
authors.affiliation: Department of Rheumatology, the Dr Daniel den Hoed Clinic, Rotterdam, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Swaak
authors.forename: A
authors.initials: A
authors.lastname: van Rooyen
authors.forename: E
authors.initials: E
authors.lastname: Nieuwenhuis
authors.forename: L A
authors.initials: LA
authors.lastname: Aarden
mesh_terms: D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D002097:C-Reactive Protein / Q000097:blood; D006073:Gout / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6; D007378:Interleukins / Q000032:analysis* / Q000097:blood; D010003:Osteoarthritis / Q000378:metabolism*; D012709:Serum Albumin / Q000032:analysis; D013582:Synovial Fluid / Q000032:analysis*
chemical_list: D015850:Interleukin-6; D007378:Interleukins; D012709:Serum Albumin; D002097:C-Reactive Protein