Résumé : In this study, we have examined the immunohistochemical localization of cell adhesion molecules in the lesions of generalized pustular psoriasis (GPP) (n = 6). The intercellular adhesion molecule-1 (ICAM-1) and endothelial leucocyte adhesion molecule-1 (E-selectin) were predominantly expressed on endothelial cells of microvessels in the papillary dermis, and E-selectin was restricted to the upper dermis. ICAM-1 also showed focal expression on the keratinocytes below the subcorneal microabscess. Staining intensity of both ICAM-1 and E-selectin did not show any significant differences between the involved skin of psoriasis vulgaris and GPP. Soluble ICAM-1 and E-selectin were measured by enzyme-linked immunosorbent assay in 6 patients with GPP, in 4 patients with severe psoriasis vulgaris (mean PASI score; 25.4) and in normal subjects. The median level of sICAM-1 in patients with GPP (426.9 ± 87.1 ng/ml) was significantly higher than that of patients with PV (328 ± 21.7 ng/ml) (p < 0.05) and normal controls (170.5 ± 60.3 ng/ml) (p < 0.005). Median levels of sE-selectin in patients with GPP (106.2 ± 32.8 ng/ml) were not significantly higher than those in patients with PV (83.8 ± 26.0 ng/ml), but were significantly higher than those of normal controls (41.5 ± 15.3 ng/ml) (p < 0.005). Our results suggest that these adhesion molecules may play a crucial role in the pathogenesis of GPP.