Exogenous enzymatic modulation of lectin binding sites in human tissue. Development of hemolysis in hemolytic-uremic syndrome (HUS) considering alteration of the glycocalyx in the erythrocyte membrane.

ABSTRACT

FITC-labelled lectins (DBA, PNA, RCAI, UEAI) with different carbohydrate specificity were used to look for possible alterations of the glycocalyx of erythrocyte membrane in patients with hemolytic uraemic syndrome (HUS; n = 34) in comparison with controls (n = 66). These investigations revealed that patients with the blood group A, B and O possess a significantly higher amount of sialic acid covered binding sites for PNA (p less than 0.05) on the membrane of red blood cells than controls, as measured by quantitative fluorescence microscopy. This significant difference was additionally found for sialic acid substituted RCAI binding sites on B erythrocytes (p less than 0.05). Without pretreatment of red blood cells with neuraminidase a significant difference between HUS patients and controls was observed for PNA on A, for RCAI on O and for UEAI on A erythrocytes. The measured values are influenced by contamination of red blood cells with serum glycoproteins as could be assessed by the lower values on washed erythrocytes. As a whole the results indicate that the composition of the glycocalyx in red blood cells of HUS patients seems to be altered and that the pathogenesis of this syndrome is additionally influenced by serum factors. With the exception of UEAI that possesses a significant higher amount of binding sites on washed erythrocytes of blood group O the other lectins used are not suitable for the demonstration of blood group specificity.