ANALYSIS OF ADHESION MOLECULE EXPRESSION BY TUBULAR EPITHELIAL-CELLS USING URINE IMMUNOCYTOLOGY

On their surface, renal tubular cells present intercellular adhesion m olecule-1 (ICAM-1) during acute renal allograft rejection. We propose that the extent of ICAM-1 expression by renal tubular cells can be est imated from urine immunocytology. To test this hypothesis, we obtained 52 samples of urine from 32 renal transplant recipients with either a cute tubular necrosis, rejection or stable renal function. Cytocentrif uged aliqtrots of urinary sediment were incubated with monoclonal anti bodies to ICAM-1 in an avidin-biotin-peroxidase technique. To corrobor ate our findings, biopsy specimens were obtained for conventional and immunohistology one hour following vascular anastomosis and during rej ection episodes. The proportion of renal tubular cells that expressed ICAM-1 was low in patients with acute tubular necrosis (23.8 +/- 3.6%) and high in patients with rejection (53.1 +/- 4.4% [SEM]) (P <.002). In 11 patients who recovered from rejection, the proportion of ICAM-1- positive renal tubular cells decreased from 55.9 +/- 5.6% to 25.5 +/- 4.3% (P <.05). In two patients who initially had acute tubular necrosi s and then rejected their transplants, the expression of ICAM-1 on ren al tubular cells tended to increase (from 27.5 +/- 2.5% to 60.0 +/- 20 .0%, P=.12). In eight patients with acute tubular necrosis who never r ejected their transplants, ICAM-1 expression remained low (23.1 +/- 3. 8%). Immunocytology correlated well with immunohistology and the clini cal diagnosis. Our findings suggest that urine immunocytology may be u seful in monitoring adhesion molecule expression by renal tubular cell s.