BACKGROUND: Adhesion molecules and their ligands are involved in coordination of the activities of the immune system. OBJECTIVE: To evaluate whether adhesion molecules are relevant in the pathogenesis of inflammatory dermatoses, we analyzed the expression pattern of many of these molecules. METHODS: The expression of 10 members of the integrin and immunoglobulin superfamilies was mapped by means of immunohistochemical techniques in biopsy specimens of psoriasis (n = 15), pityriasis lichenoides (n = 11), parapsoriasis en plaques (n = 11), contact dermatitis (n = 7), and lichen planus (n = 5). RESULTS: In all investigated skin diseases, almost every infiltrating cell expressed lymphocyte function-associated antigens 1 and 3 as well as very late activation (VLA) antigens 4 and 5. The subepidermal infiltrate differed with regard to the expression of VLA-1, VLA-3, and VLA-6, which was high in lichen planus and moderate or absent in the other dermatoses. The intraepidermal lymphocytes in psoriasis and pityriasis lichenoides were VLA-1 positive, whereas the subepidermal infiltrate lacked this marker. CONCLUSION: The differential upregulation of adhesion molecules in the mononuclear infiltrate and on keratinocytes demonstrates their importance in the pathogenesis of cutaneous inflammation.