Apoptosis of renal tubular cells in shiga-toxin-mediated hemolytic uremic syndrome

In order to clarify the mechanism of unusual renal tubular dysfunction seen in a child with Shiga toxin (Stx)mediated hemolytic uremic syndrome (HUS), we studied the renal biopsy specimens for Stx binding and apoptosis of ren al tubular cells. A 7-year-old boy with Stx-2-mediated HUS demonstrated ext ensive renal tubular damage characterized by nonoliguric acute renal failur e, increased urinary tubular enzymes and defective urine-concentrating capa city, His renal biopsy specimens were analyzed for Stx binding and apoptoti c cell death. Seven kidney tissue specimens obtained from patients without HUS served as controls. Detection of Stx binding to renal sections and apop totic cells were performed using mouse monoclonal anti-Stx 2 antibody and t he TUNEL method, respectively. Positive staining was observed predominantly in renal tubular cells, while the 7 kidney tissue specimens from control p atients did not show positive staining. To the best of our knowledge, this is the first case to show Stx binding and apoptotic cell death in renal tub ules on biopsy specimens obtained from a child with Stx-mediated HUS. In co nclusion, this case suggests that vascular endothelial cells are not the so le nor the consistent target for Stx-mediated cell injury and that signific ant renal tubular damage other than glomerular damage might occur in some c hildren with Stx-mediated HUS. Copyright (C) 2001 S. Karger AG, Basel.