title: Interleukin-6 in relation to other proinflammatory cytokines, chemotactic activity and neutrophil activation in rheumatoid synovial fluid.
abstract: OBJECTIVE
  To evaluate the relation between synovial fluid (SF) concentrations of interleukin-6 (IL-6) and other mediators of inflammation which are responsible for joint degradation in rheumatoid arthritis (RA).
  
  
  METHODS
  We measured IL-6, IL-1 beta, tumour necrosis factor alpha (TNF alpha), granulocyte macrophage colony stimulating factor, IL-8, and polymorphonuclear leucocyte (PMNL) chemotaxis and degranulation in SF from patients with RA (n = 30) in the early phase of the disease.
  
  
  RESULTS
  In a cross-sectional study IL-6 concentrations correlated with those of IL-1 beta, IL-8 and with PMNL activation as reflected by lactoferrin concentrations. In a longitudinal study, changes in IL-6 concentrations correlated with changes in TNF alpha, IL-8 and lactoferrin concentrations.
  
  
  CONCLUSIONS
  IL-6 in SF appears to reflect the local proinflammatory, potentially erosive activity in RA. This supports the use of acute phase proteins, which are mainly induced by IL-6, as variables to monitor the course of RA.
authors.affiliation: Department of Rheumatology, University Hospital Groningen, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: van Leeuwen
authors.forename: J
authors.initials: J
authors.lastname: Westra
authors.forename: P C
authors.initials: PC
authors.lastname: Limburg
authors.forename: P L
authors.initials: PL
authors.lastname: van Riel
authors.forename: M H
authors.initials: MH
authors.lastname: van Rijswijk
mesh_terms: D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D002634:Chemotaxis, Leukocyte / Q000502:physiology*; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis; D006801:Humans; D007375:Interleukin-1 / Q000032:analysis; D015850:Interleukin-6 / Q000032:analysis*; D016209:Interleukin-8 / Q000032:analysis; D007781:Lactoferrin / Q000032:analysis; D018375:Neutrophil Activation / Q000502:physiology*; D011446:Prospective Studies; D013582:Synovial Fluid / Q000737:chemistry*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
chemical_list: D007375:Interleukin-1; D015850:Interleukin-6; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D007781:Lactoferrin