title: Immunohistochemical markers for arthritis in psoriasis.
abstract: OBJECTIVE
  To examine the immunohistological features in the involved skin of patients with psoriatic arthritis (PA) (n = 15), compared with those in involved skin from patients with psoriasis but no arthritis (n = 5), and with a group with normal skin (n = 4), to identify markers for arthritis in psoriasis.
  
  
  METHODS
  Skin was obtained from patients by 6 mm punch biopsy and normal skin was provided by the department of plastic surgery. Samples were stained with monoclonal antibodies against T cells (CD3, CD8, CD4, CD45Ro), B cells (CD20), macrophages (mac387), vascular endothelium (FVIII-related antigen) and a Langerhan's cell marker (p155). The number of cells/vessels staining with each monoclonal antibody was calculated and serial sections of skin were examined to estimate the presence of DR+ keratinocytes.
  
  
  RESULTS
  There were significantly more CD45Ro T-cells and blood vessels in patients with psoriatic arthritis compared with both psoriasis alone, and with normal controls (p < 0.02). While B-cells were not seen in psoriasis without arthritis or in normal skin, a small but significant number were observed in PA (p < 0.02). Furthermore, while DR+ keratinocytes were present in both psoriatic arthritis and psoriasis skin, there were significantly more DR+ cells in the psoriatic arthritis epidermis compared with psoriasis alone (p < 0.02).
  
  
  CONCLUSIONS
  This study suggests that increased numbers of CD45Ro T-cells, greater vascularity, the presence of B-cells, and increased numbers of DR+ epidermal cells are markers for arthritis in patients with psoriasis.
authors.affiliation: St Vincent's Hospital, Department of Rheumatology, Dublin, Ireland.
authors.forename: D J
authors.initials: DJ
authors.lastname: Veale
authors.forename: L
authors.initials: L
authors.lastname: Barnes
authors.forename: S
authors.initials: S
authors.lastname: Rogers
authors.forename: O
authors.initials: O
authors.lastname: FitzGerald
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D015535:Arthritis, Psoriatic / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D015415:Biomarkers; D005260:Female; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000276:immunology; D016131:Lymphocyte Subsets / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000098:blood supply / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D006684:HLA-DR Antigens; D017493:Leukocyte Common Antigens