Beta-glucuronidase-positive erythrocytic inclusion bodies--a hitherto unknown phenomenon.

A combined cytochemical and electron microscopical study has delineated a new type of an erythrocytic inclusion body. Enzyme cytochemically these inclusions are characterized by beta-glucuronidase as a marker enzyme. In part, the inclusions may contain acid phosphatase and ferritin. The inclusions develop in mature erythrocytes since beta-glucuronidase normally does not occur in erythroblasts and, in general, this type of inclusion body is not found in erythroblasts. Based upon our preliminary findings, the hypothesis is extended that beta-glucuronidase is taken up via receptor-mediated endocytosis into erythrocytes and is finally put into clustered cytolysosomal vaculoes, that account for the inclusion bodies as seen at light microscopy. Exogenous beta-glucuronidase might be contributed for by breakdown of cells (e.g. hepatocytes) producing this enzyme in considerable amounts numbers. This view is corroborated by the observation that most patients with beta-glucuronidase-positive inclusions suffered from various chronic disorders of the liver.