We investigated ICAM-1/CD54 tissue immunoreactivity and serum levels of its soluble form (sICAM-1) in patients with Hodgkin's disease (HD) at diagnosis. ICAM-1 was strongly expressed in involved tissues, and sICAM-1 serum levels were higher in HD (79 patients) than in controls (P < 0.01), and in patients with more advanced or more active disease (stages III + IV vI + II: P = 0.002; stage 'B' v 'A': P < 0.0001; 'bulky' disease v non-'bulky': P = 0.042). We suggest that tissue ICAM-1 overexpression leading to increase of circulating sICAM-1 may interfere with the lymphocyte adhesion machinery thus contributing to the well-known immune derangement of HD.