Circulating intercellular adhesion molecule-1 in chronic hepatitis C patients with normal or elevated...

Intercellular adhesion molecule-1 (ICAM-1) plays a fundamental role during liver inflammation. In fact, weak ICAM-1 expression is physiologically restricted to the endothelium of portal vessels and to sinusoidal lining cells, but it becomes markedly evident on sinusoidal lining cells and at the surface of hepatocytes during inflammatory liver diseases. The aim of this study was to evaluate the behaviour of soluble ICAM-1 (sICAM-1) in chronic hepatitis C (CH-C) patients with persistently normal aminotransferase in comparison with patients with CH-C and elevated aminotransferase, and its changes during alpha-interferon (IFN) therapy. Immunohistochemical localization of ICAM-1 was also performed on liver tissue specimens of both groups.

Sixty subjects were divided into 3 groups: group A included 19 patients with CH-C and persistently normal aminotransferase; group B included 21 patients with CH-C and persistently elevated aminotransferase levels, and group C included 20 healthy subjects representing the control group. The first two groups were treated with recombinant alpha-IFN 2b at a dose of 6 MU 3 times a week for 3 months and followed up with 3 MU 3 times a week for another 3 months.

Baseline values of serum ICAM-1 in groups A and B were significantly higher than those in group C (p < 0.0001). The median baseline value of sICAM-1 in group A (525.0 ng/ml) was lower than that of group B (561.0 ng/ml), but the difference was not statistically significant. Furthermore, there was a trend toward higher ICAM-1 values as histological severity increased (Mantel-Haenszel chi(2) 8.8, p < 0.003). Post-treatment sICAM-1 serum values showed a marked decrease in both groups, but only among responder patients, while ICAM-1 levels were unchanged in non-responders. Immunohistochemical localization showed no staining for ICAM-1 in normal liver specimens, while there was a quite similar staining for ICAM-1 in the two groups of patients, consistent with an inflammatory process.

This study shows that circulating ICAM-1 levels in most patients with CH-C and persistently normal aminotransferase are higher than those in a control group and the fact that ICAM-1 molecules are also expressed on the hepatocyte membrane suggests that they could play an important role, in association with other molecules, in the intercellular adhesion processes during the induction and maintenance phases of the immune response. In both groups, only patients responding to alpha-IFN therapy showed a marked decrease in serum ICAM-1 below baseline values.