Reduced synovial membrane macrophage numbers, ELAM-1 expression, and lining layer hyperplasia in psoriatic arthritis as compared with rheumatoid arthritis

Arthritis Rheum. 1993 Jul;36(7):893-900. doi: 10.1002/art.1780360705.


Objective: To define the immunohistologic features of the synovial membrane (SM) of patients with psoriatic arthritis (PA) and to compare them with those of an age- and disease-duration-matched population of patients with rheumatoid arthritis (RA).

Methods: Synovial membrane needle biopsy was performed on 15 PA patients with knee involvement (8 had asymmetric oligoarthritis and 7 had symmetric polyarthritis) and on 15 RA controls. Specimens were stained with monoclonal antibodies against T cells (CD3, CD8, CD4, CD45RO), B cells (CD20), macrophages (Mac387, CD14), and cells bearing class II antigens (DAKO-DR). Vascular endothelium was examined using a polyclonal antibody to Factor VIII-related antigen, and adhesion molecule expression was examined using antibodies 1.3B6, 6.5B5, and 1.4C3, which identify endothelial leukocyte adhesion molecule 1 (ELAM-1), intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1), respectively.

Results: There was significantly less lining layer hyperplasia, fewer macrophages, and a greater number of blood vessels in PA SM than in RA SM: ELAM-1 expression was less intense in PA than in RA SM, while there was no difference in expression of ICAM-1 and VCAM-1. Numbers of B cells, T cells, and T cell subsets (predominantly CD4, CD45RO T cells) were similar in both groups of patients.

Conclusion: Our findings demonstrate important differences in the immunohistologic features of PA and RA SM: The PA SM is more vascular, ELAM-1 expression is less intense, and fewer macrophages invade the stroma and migrate to the lining layer than in RA SM: However, the lymphocytic infiltrate in the SM of both groups is similar.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Arthritis, Psoriatic / pathology*
  • Arthritis, Rheumatoid / pathology*
  • CD4 Antigens / analysis
  • Cell Adhesion Molecules / analysis*
  • Cell Count
  • E-Selectin
  • Endothelium, Vascular / chemistry
  • Female
  • Humans
  • Hyperplasia
  • Immunohistochemistry
  • Leukocyte Common Antigens / analysis
  • Macrophages / chemistry
  • Macrophages / pathology*
  • Middle Aged
  • Synovial Membrane / pathology*
  • T-Lymphocytes / immunology


  • CD4 Antigens
  • Cell Adhesion Molecules
  • E-Selectin
  • Leukocyte Common Antigens