Haematology of the haemolytic uraemic syndrome.

The Haemolytic Uraemic Syndrome (HUS), characterised by a microangiopathic haemolytic anaemia, thrombocytopenic purpura and renal failure, is the commonest cause of acute renal failure in children. Most cases of HUS are associated with enteropathogenic Escherichia coli which elaborate an exotoxin called verotoxin. Verotoxin has been shown to produce red cell abnormalities and induce a platelet aggregating activity. It also exerts a cytopathic effect on cultured endothelial cells. These findings are discussed in relation to the pathogenesis of HUS. Recent studies demonstrating homology between the verotoxin glycolipid receptor and the red cell P group antigens have led to the hypothesis that variability in the expression of these red cell antigens may account for the marked individual variations in the degree of organ damage in children with HUS. This hypothesis could provide a criterion for rational immunisation of at risk children.