Familial combined hyperlipidemia (FCH) is the most common familial hyperlipidemia with a high risk for early atherosclerosis. The aim of this study was to compare levels of soluble intercellular cell adhesion molecule 1 (s-ICAM-1) and soluble vascular cell adhesion molecule 1 (s-VCAM-1) in asymptomatic members of FCH families with healthy controls and to determine the relation between s-ICAM-1, s-VCAM-1 and risk factors accompanying FCH. We also investigated the association between adhesion molecules and the intima-media thickness (IMT) of the common carotid artery, a recognized morphological marker of early atherosclerosis. 82 members of 29 FCH families were divided into the 2 groups: HL (probands and hyperlipidemic first-degree relatives, n = 47) and NL (normolipidemic first-degree relatives, n = 35). The control groups--HL-C (n = 20) and NL-C (n = 20)--consisted of sex- and age-matched healthy individuals. Hyperlipidemic members had significantly higher concentration of s-ICAM-1 (633.7 +/- 169.6 ng/ml versus 546.2 +/- 155.9 ng/ml, p < 0.05). The elevation of s-VCAM-1 was not significant (880.8 +/- 202.9 ng/ml versus 826.5 +/- 174.6 ng/ml, N.S.). Levels of s-ICAM-1 and of s-VCAM-1 in normolipidemic relatives were not significantly different from the control group (530.8 +/- 113.9 ng/ml versus 530.0 +/- 101.0 ng/ml and 860.2 +/- 265.7 ng/ml versus 822.1 +/- 197.0 ng/ml respectively). There was a significant correlation between s-ICAM-1 and apoB (r = 0.42; p < 0.01) in hyperlipidemic subjects and between s-ICAM-1 and proinsulin (r = 0.54; p < 0.01) in normolipidemic subjects. S-ICAM-1 correlated with IMT (r = 0.32; p < 0.05) in all members of FCH families. The increase of s-ICAM-1 in asymptomatic hyperlipidemic members of FCH families reflects their high cardiovascular risk. The positive association between s-ICAM-1 and IMT could indicate s-ICAM-1 as a potential predictor of atherosclerosis manifestation.