title: Elevated levels of synovial fluid antibodies reactive with the small proteoglycans biglycan and decorin in patients with rheumatoid arthritis or other joint diseases.
abstract: OBJECTIVE
  To determine whether patients with rheumatoid arthritis (RA) express humoral immunity to the small proteoglycans biglycan and decorin and to compare the response to that of patients suffering from other joint diseases.
  
  
  METHODS
  Serum and synovial fluid IgG and IgM antibody levels were determined by enzyme-linked immunosorbent assay. Antibodies to biglycan and decorin as well as to other known and extensively investigated cartilage matrix components such as type II collagen, aggrecan and fibronectin were investigated. Patients suffering from RA, osteoarthritis (OA), psoriatic arthritis and other seronegative spondylarthropathies were included in the study. Correlation between antibody levels and clinical/laboratory parameters was determined.
  
  
  RESULTS
  Patients with RA expressed an increased humoral immunity to biglycan, while patients with seronegative spondylarthropathies displayed elevated decorin-specific synovial antibody levels compared with OA patients.
  
  
  CONCLUSIONS
  These results indicate a significantly higher immunity to small proteoglycans in RA and seronegative spondylarthropathies than in OA suggesting a possible involvement in the pathogenesis of inflammatory rheumatic diseases.
authors.affiliation: National Institute of Rheumatology and Physiotherapy, Budapest, Hungary.
authors.forename: A
authors.initials: A
authors.lastname: Polgár
authors.forename: A
authors.initials: A
authors.lastname: Falus
authors.forename: E
authors.initials: E
authors.lastname: Koó
authors.forename: I
authors.initials: I
authors.lastname: Ujfalussy
authors.forename: M
authors.initials: M
authors.lastname: Seszták
authors.forename: I
authors.initials: I
authors.lastname: Szuts
authors.forename: K
authors.initials: K
authors.lastname: Konrád
authors.forename: L
authors.initials: L
authors.lastname: Hodinka
authors.forename: E
authors.initials: E
authors.lastname: Bene
authors.forename: Gy
authors.initials: G
authors.lastname: Mészáros
authors.forename: Zs
authors.initials: Z
authors.lastname: Ortutay
authors.forename: E
authors.initials: E
authors.lastname: Farkas
authors.forename: A
authors.initials: A
authors.lastname: Paksy
authors.forename: E I
authors.initials: EI
authors.lastname: Buzás
mesh_terms: D000328:Adult; D000368:Aged; D015535:Arthritis, Psoriatic / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis*; D001324:Autoantigens / Q000276:immunology; D058578:Biglycan; D002358:Cartilage, Articular / Q000276:immunology; D058575:Decorin; D004797:Enzyme-Linked Immunosorbent Assay; D016326:Extracellular Matrix Proteins; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000276:immunology; D011509:Proteoglycans / Q000276:immunology*; D025242:Spondylarthropathies / Q000276:immunology; D013582:Synovial Fluid / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; C546884:BGN protein, human; D058578:Biglycan; C546878:DCN protein, human; D058575:Decorin; D016326:Extracellular Matrix Proteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011509:Proteoglycans