Sjögren's syndrome is a systemic autoimmune disease characterized by focal lymphocytic infiltration of the salivary and lacrimal glands. Expression and up-regulation of adhesion molecules and activation of cellular immune system is essential for the migration of inflammatory cells into tissues. Soluble forms of adhesion molecules sICAM-1, sVCAM-1, sE-selectin and neopterin were analyzed in serum of 17 patients with primary Sjögren's syndrome and 11 patients with secondary Sjögren's syndrome together with 26 age-matched healthy blood donors. There were significantly higher serum concentrations (mean +/- 1SD) of sICAM-1 (362.0 +/- 67.9 ng/ml, p < 0.001), sE-selectin (78.7 +/- 28.1 ng/ml, p < 0.001) and neopterin (17.9 +/- 6.4 nmol/l, p < 0.001) in primary Sjögren's syndrome patients in comparison to control group (sICAM-1: 128.3 +/- 46.9 ng/ml, sE-selectin: 46.3 +/- 39.5 ng/ml, and neopterin: 7.6 +/- 2.3 nmol/l). Sera from patients with secondary Sjögren's disease contained significantly higher levels of sICAM-1 (356.0 +/- 62.4 ng/ml, p < 0.001), sE-selectin (65.5 +/- 27.0 ng/ml, p < 0.05), and neopterin (18.8 +/- 9.8 nmol/l, p < 0.001) in comparison with control group. There were no significant differences between patients with primary and secondary Sjögren's syndrome in any parameters tested. No statistically significant differences in serum levels of sVCAM-1 were found either in patients with primary or secondary SS compared to control group.