Circulating soluble adhesion molecules in patients with classical polyarteritis nodosa

The objective was to evaluate whether changes in circulating soluble adhesion molecule levels reflect disease activity in patients with systemic polyarteritis nodosa (PAN). A sandwich ELISA was used to measure soluble (s) intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1 (sVCAM-1), E-selectin, L-selectin and P-selectin in sera and plasma from 22 patients with active PAN, in sera from 13 of these patients taken serially during follow-up, and in sera from 13 healthy controls. At the time of diagnosis, sICAM-1, sVCAM-1 and sE-selectin levels (488.5 +/- 201.3, 1176.5 +/- 514.1 and 60.6 +/- 27 ng/ml, respectively) were significantly higher in patients than in controls (P < 0.0001, P = 0.001 and P = 0.003, respectively). In contrast, sL-selectin levels tended to be lower in patients than in controls. Within the first 7 days after starting treatment, there was a significant increase in sICAM-1 concentrations, which fell thereafter, but did not completely reach normal levels when patients achieved clinical remission. sE-selectin also remained elevated during follow-up. Only sVCAM-1 decreased, tending to reach normal values in inactive disease. Increased levels of sICAM-1, sVCAM-1 and sE-selectin, and decreased levels of sL-selectin, in active PAN suggest immune and endothelial stimulation during disease activity. Abnormal levels of soluble adhesion molecules in clinically inactive patients might reflect persistence of immune activation and/or endothelial cell exposure to a remaining inflammatory microenvironment.