New kind of cytoplasmic inclusions of plasma cells in acid maltase deficiency.

Extensive 'vacuolization' could be demonstrated in nearly all plasma cells and in some lymphocytes of an adult with glycogenosis type II (Pompe's disease). The biochemically defined diagnosis acid maltase deficiency (AMD) could be ascertained by examination of the maltase activity of the patient's leukocytes. Electron microscopical, microspectrographic, and cytochemical investigations revealed electron dense inclusions, which show an UV absorption at 276 nm and a positive reaction after PAS staining of plastic embedded material. Since no other abnormalities of the plasma cells could be found, our results are presumably indicative for a connection of AMD and a glycoprotein storage in the plasma cells of the patient.