CHARACTERIZATION OF ADHESION MOLECULE EXPRESSION IN THE PATHOGENESIS OF HOMOLOGOUS COLLAGEN-INDUCED ARTHRITIS IN THE DA RAT

We have investigated the inflammatory cell infiltrates and adhesion mo lecule expression in the synovial fluid (SF) and synovial membranes (S M) of rats with homologous collagen-induced arthritis. Immunohistochem ical staining revealed that the majority of the cells in the SF were g ranulocytes, expressing CD11b and CD11c. In SM, the majority of the ce lls were monocytes/macrophages. CD49d and CD49f were expressed mainly in the erosion zone in SM, and ICAM-1 was expressed in the lining laye r, in the capillaries, and in the erosion zone. In SF 7% of the cells were ICAM-1 positive, CD2 was more abundant in SM than in SF. These fi ndings might explain the difference in granulocyte counts between SF a nd SM. CD49d and CD49f expression might retain lymphocytes and monocyt es in SM, while granulocytes not expressing CD49d and CD49f are not re tained. (C) 1997 Academic Press.