SYNOVIAL EXPRESSION OF CELL-ADHESION MOLECULES IN POLYMYALGIA-RHEUMATICA

Polymyalgia rheumatica (PMR) is a common disorder of the elderly: the pathogenesis of the syndrome is still debated, though active synovitis of the shoulder has recently been confirmed, To investigate the patho genesis of this synovitis we evaluated cell adhesion molecule (CAM) ex pression in shoulder synovial tissue from patients with PMR, correlate d synovial expression with the serum levels of soluble forms, and asse ssed the changes associated with corticosteroid treatment. Arthroscopi c synovial biopsies were obtained from 12 untreated and seven corticos teroid (CS)-treated cases. CAM expression was evaluated by MoAb staini ng on frozen sections and computerized image analysis. Soluble CAM wer e quantified by ELISA. Endothelial cells expressed intercellular adhes ion molecule-1 (ICAM-1), E- and P-selectins. Infiltrating cells were I CAM-1 and beta(1)-integrin-positive, while L-selectin expression was l imited to intravascular leucocytes. Synovial lining cells strongly exp ressed vascular cell adhesion molecule-1 (VCAM-1), and less intensely ICAM-1. Only the soluble form of ICAM-1 (sICAM-1) was Elevated in untr eated patients. CS treatment was associated with a decrease in ICAM-1, VCAM-1 and E- and P-selectin expression. sICAM-1 levels were in the n ormal range in treated patients. VLA-5 and 6 expression was widely dis tributed among cell types, and was not CS-sensitive. Active shoulder s ynovitis is associated with different CAM expression in PMR. ICAM-1 ex pression is widely distributed and correlates with elevated levels of the soluble form: it is significantly lower in CS-treated asymptomatic cases.