The expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) is increased in immune-mediated diseases. These adhesion molecules promote the adherence of inflammatory cells to parenchymal target cells. We have examined the effect of immunosuppressants on the expression of ICAM-1 and VCAM-1 in a renal tubular epithelial cell line. We found that dexamethasone (4-40 mug/mL), the azathioprine metabolite 6-mercaptopurine (10-100 mug/mL) and cyclosporine A (0.1-1 mug/mL) have no effect on the basal and the tumor necrosis factor-alpha- or interleukin-1-stimulated expression of these adhesion molecules. We conclude that these immunosuppressants do not directly influence the expression of ICAM-1 and VCAM-1 by renal tubular epithelium.