title: Comparable histological appearance of synovitis in seropositive and seronegative rheumatoid arthritis.
abstract: OBJECTIVE
  To compare the histological characteristics of the synovium between seropositive and seronegative rheumatoid arthritis (RA), synovial tissue was obtained from 19 patients with rheumatoid factor-positive (RF+) RA, 11 with rheumatoid factor-negative (RF-)RA and 11 non-RA controls.
  
  
  RESULTS
  There were no differences in the frequency of each histological feature or histological scores between RF+ and RF-RA. However, significant differences in the frequency of histological findings such as lining cell proliferation and inflammatory cell infiltration were found both between RF+ RA and non-RA controls, and between RF-RA and non-RA controls. Analysis of clinical parameters and histology in all RA patients revealed that the level of serum C-reactive protein and the erythrocyte sedimentation rate were directly correlated with the inflammatory cellular infiltration score. Immunohistological staining using a monoclonal antibody against IgM rheumatoid factor (RF) was positive in some plasma cells in the synovium of both RF+ and RF-RA patients, while no IgM-RF-positive cells were observed in the synovium of non-RA controls.
  
  
  CONCLUSIONS
  RF serostatus does not necessarily reflect the histology of synovial inflammation.
authors.affiliation: Division of Clinical Immunology, International Medical Center of Japan, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Fujinami
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: S
authors.initials: S
authors.lastname: Kashiwazaki
authors.forename: S
authors.initials: S
authors.lastname: Aotsuka
mesh_terms: D000911:Antibodies, Monoclonal; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology* / Q000473:pathology*; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis; D008875:Middle Aged; D012217:Rheumatoid Factor / Q000032:analysis*; D013583:Synovial Membrane / Q000473:pathology; D013585:Synovitis / Q000097:blood / Q000473:pathology*
chemical_list: D000911:Antibodies, Monoclonal; D007075:Immunoglobulin M; D002097:C-Reactive Protein; D012217:Rheumatoid Factor