Localization of Shiga toxins of enterohaemorrhagic Escherichia coli in kidneys of paediatric and geriatric patients with fatal haemolytic uraemic syndrome

Haemolytic uraemic syndrome (HUS) is characterized by haemolytic anaemia, t hrombocytopenia and renal failure. Infection with enterohaemorrhagic Escher ichia coli (EHEC), mainly O157:H7, has been strongly implicated as the majo r cause of HUS in children. The pathogenesis of HUS caused by the infection is not well understood and the defined sites of Stx in kidney of EHEC-infe cted humans has not been clearly demonstrated. The aim of this study was to investigate and compare the locations of Stx deposition in kidneys of paed iatric and geriatric patients who died from enterohaemorrhagic E. coli O157 (EHEC) associated HUS, using an immunoperoxidase staining of the tissues. The study revealed that binding of Stx was relatively less and limited only to the renal tubules of an adult case (81 years old), while more binding w as found at both renal tubules and glomeruli of an infant case (21 months o ld). The Stx binding in the infant's glomeruli was at podocytes, mesangial and endothelial cells. It has been known that young children are more susce ptible than adults to HUS. One possibility for this is that the more extens ive binding of the Stx to the kidney tissue of the paediatric patient might be due to the higher synthesis and expression of Stx receptors, i.e. Gb(3) , in infants and less so in the aged individuals. However, other alternativ es are possible, for example, the difference in stage of HUS in individual patients. Thus it is too early to draw any conclusion on this enigma and fu rther investigation is required. (C) 2001 Academic Press.