Immunocytochemical analysis of normal and acid maltase-deficient muscle cultures

Muscle cultures from patients with infantile and later-onset acid maltase deficiency (AMD) and from unaffected controls were studied immunocytochemically with anti-acid maltase (anti-AM) antibodies and fluorescein-labeled goat anti-rabbit IgG second antibody. In control muscle cells, an intense granular distribution of staining was seen, consistent with lysosomal localization of AM. Cultured muscle cells from two patients with infantile AMD (Pompe's disease) did not fluoresce, whereas cells from two patients with AMD of later onset did fluoresce, showing a distribution similar to that of controls.