title: The synovial membrane of healthy individuals--immunohistochemical overlap with synovitis.
abstract: The synovial membrane of healthy volunteers was analysed by immunohistochemical staining of biopsies sampled under direct vision at arthroscopy or obtained blindly by needle. Infiltrating Leu-4+ T lymphocytes were found scattered in all biopsies but frequently also perivascularly accumulated. A majority of the synovial lining cells expressed either the OKM1 monocyte/macrophage marker or HLA-DR antigens. Some OKM1- HLA-DR+ lining cells also expressed the Leu-3a T 'helper' cell marker. In the sublining tissue non-lymphoid cells with varying morphology including macrophage- and fibrocyte-like cells were found expressing either HLA-DR, or Leu-3a, or both antigens simultaneously, whereas OKM1+ macrophage-like sublining cells were rare. The perivascular T lymphocyte accumulation as well as the phenotypic heterogeneity of infiltrating and residing cells, previously thought indicative of synovitis, were thus also found in the synovial membrane of healthy individuals.
authors.affiliation: Department of Rheumatology, Karolinska Institute, Huddinge University Hospital, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Lindblad
authors.forename: E
authors.initials: E
authors.lastname: Hedfors
mesh_terms: D000328:Adult; D001182:Arthroscopy; D002465:Cell Movement; D005260:Female; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007124:Immunoenzyme Techniques; D007719:Knee Joint / Q000276:immunology; D008297:Male; D013583:Synovial Membrane / Q000276:immunology*; D013585:Synovitis / Q000276:immunology*; D013601:T-Lymphocytes / Q000502:physiology
chemical_list: D006684:HLA-DR Antigens