Cell surface adhesion molecules mediate important cellular interactions in acute and chronic inflammatory responses. Soluble forms of a number of adhesion molecules are generated either by proteolytic cleavage or alternate mRNA splicing. The function of soluble adhesion molecules is unknown, but they may play a regulatory role in inflammatory processes. Studies of these molecules in adult autoimmune diseases have furthered our understanding of these conditions, but such studies have been lacking in juvenile rheumatoid arthritis (JRA). We therefore studied serum levels of soluble forms (s) of ICAM-1, E-selectin, L-selectin, VCAM-1, and ICAM-3 by sandwich ELISA in 16 children with JRA (6 systemic, 6 polyarticular, 4 pauciarticular). We analyzed differences in levels of these molecules among JRA subtypes by ANOVA, and also correlated these levels with erythrocyte sedimentation rate (ESR), hematocrit, white blood cell count (WBC), and total platelet (PLT) counts, joint count, and duration of morning stiffness by linear regression analysis.RESULTS: sE-selectin levels were significantly higher in patients with systemic disease as compared to other subtypes (p<.04). Furthermore, there was a trend toward higher levels of sICAM-1 in systemic disease, but the difference did not reach statistical significance. Significant correlations were found between sE-selectin and ESR(r=.68,p<.006), WBC (r=.70,p<.003), and PLT (r=.54,p<.05), and between sL-selectin and WBC (r=.55,p<.03). We conclude that levels of sE-selectin, and possibly sICAM-1 are relatively elevated in systemic JRA, and may indicate cytokine induction and endothelial cell activation in that subtype. Several molecules, especially sE-selectin, correlated with hematologic parameters inJRA. This suggests that serum levels of these molecules may provide a useful additional marker for disease activity in certain patients.Funded by Boehringer Ingelheim Pharmaceuticals