Lectin histochemistry and ultrastructure of kidneys from patients with I-cell disease.

The undegraded stored material in I-cell disease (ICD) includes mucopolysaccharides, lipids, and oligosaccharides. We used ten different lectins as histochemical probes to identify specific carbohydrate residues in stored materials, and electron microscopy to examine the morphology of abnormally stored material in kidneys from two patients with ICD. In both cases, all the glomerular epithelial cells (ie, podocytes), endothelial cells, and renal tubular cells were enlarged and vacuolated. Ultrastructural studies revealed both fibrillogranular material and lamellated membrane structures in the vacuoles. The cytoplasm of affected cells stained with Concanavalia ensiformis agglutinin, wheat-germ agglutinin, and succinylated-wheat-germ agglutinin, but no corresponding control cells stained with lectins. The latter findings indicate an accumulation of N-linked oligosaccharides containing alpha-mannosyl, beta-N-acetylglucosaminyl, and sialyl residues in renal cells affected by ICD.