Adhesion molecules in untreated inflammatory arthritis: synovial expression and levels in synovial fluid and serum...

Adhesion molecules play a critical role in regulating leucocyte migration at sites of inflammation. The relationship of soluble forms in serum or synovial fluid (SF) to synovial membrane expression in inflammatory arthritis is controversial. We examined soluble intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin levels in matched serum and SF, and their relationship to expression in synovium obtained at the same time in 13 patients with previously untreated inflammatory arthritis. Serum-soluble (s)ICAM-1 correlated with sedimentation rate (T = 0.45), Ritchie articular index (T = 0.47) and SF sICAM-1 (T = 0.48), and SF sICAM-1 correlated with membrane ICAM-1 expression (p < 0.02). sE-selectin and sVCAM-1 levels were unrelated to disease activity or membrane expression. Membrane E-selectin expression correlated inversely with ICAM-1 expression (T = -0.57) and serum sICAM-1 (T = -0.54). Serum sE-selectin correlated inversely with membrane ICAM-1 expression (T = -0.55). The correlations observed between ICAM-1 in serum, SF, synovium and disease activity suggest that ICAM-1 could be a useful target for immunotherapy. The inverse relationship of ICAM-1 and E-selectin suggest important differences in regulation and pathogenetic roles.