AN IMPORTANT ROLE OF TUMOR-NECROSIS-FACTOR-ALPHA IN THE INDUCTION OF ADHESION MOLECULES IN PSORIASIS

Recent studies have suggested that cell adhesion plays an important ro le in the development and regulation of inflammation. To elucidate the mechanisms of regulation of adhesion molecule expression by cytokines in psoriatic lesions, we compared the expression of intercellular adh esion molecule-1, vascular cell adhesion molecule-1, E-selectin, and P -selectin immunohistochemically in involved and uninvolved psoriatic s kin with the expression of these molecules in normal skin, and measure d the amounts of tumor necrosis factor-alpha, interferon-gamma, interl eukin-1 alpha, and interleukin-1 beta in the supernatant of freeze-tha wed skin specimens using an enzyme-linked immunosorbent assay. There w as strong staining for P-selectin on endothelial cells from involved s kin. There was also strong staining for intercellular adhesion molecul e-1 on keratinocytes, dermal infiltrates, and endothelial cells from i nvolved skin and on endothelial cells from uninvolved skin, and strong staining for vascular cell adhesion molecule-1 on dermal dendritic ce lls and fibroblasts and for E-selectin on endothelial cells from invol ved skin. Large amounts of tumor necrosis factor-alpha were detected i n six out of ten specimens of involved skin, but not in uninvolved or normal skin, although interferon-gamma was detected in both involved a nd uninvolved skin to the same extent. Neither interleukin-1 alpha nor interleukin-1 beta was detected in involved skin. There was strong st aining for tumor necrosis factor-alpha on keratinocytes and endothelia l cells from involved skin. These findings suggest that tumor necrosis factor-alpha might play an important role in the induction of vascula r adhesion molecules in psoriatic lesions.