To determine serum levels of soluble (s) adhesion molecules in patients with juvenile rheumatoid arthritis (JRA), and to determine whether differences exist in these levels among the 3 subtypes of JRA, and whether levels of these molecules correlate with other measures of disease activity.
Serum levels of soluble forms of intercellular adhesion molecule-1 (ICAM-1), ICAM-3, vascular (V) CAM-1, L-selectin, and E-selectin were determined by sandwich ELISA in 16 patients with JRA (6 systemic, 6 polyarticular, 4 pauciarticular). Differences in levels among JRA subtypes were determined by ANOVA, and correlations between levels and the following clinical variables were assessed by linear regression analysis: erythrocyte sedimentation rate (ESR), total white blood cell count (WBC), hematocrit (HCT), platelet count (PLT), and total swollen joint count (JC).
sE-selectin levels were significantly higher in patients with systemic disease compared to other subtypes (p<0.04). Furthermore, there was a trend toward higher levels of sICAM-1 in systemic disease, which did not reach statistical significance. Significant correlations were found between sE-selectin and ESR (r = 0.68, p<0.006), WBC (r = 0.70, p<0.003), and PLT (r = 0.54, p<0.05) and between sL-selectin and WBC (r = 0.55, p<0.03).
Because of the small number of patients studied, and the lack of age matched control data, our results must be interpreted with caution. Nonetheless, levels of sE-selectin, and possibly ICAM-1 appear to be relatively elevated in systemic JRA, and may indicate cytokine induction and endothelial cell activation in that subtype. Several molecules, especially sE-selectin, correlate with hematologic variables in JRA. These results suggest that serum levels of these molecules may provide a useful additional marker for disease activity in certain patients.