Preponderance of lysosomal bodies in cultured fibroblasts from patients with recessive epidermolysis bullosa dystrophica. An electron microscopic study.

Fibroblasts of skin explants from three normal men and six patients with recessive epidermolysis bullosa dystrophica (EBD-R) were cultured in Dulbecco's medium, grown to confluence, sectioned and studied with the electron microscope. The normal control fibroblasts from the 6th to 13th passage (secretory phase) showed irregular or lobed nuclei with centrally scattered chromatin. They also had prominent RER, Golgi complexes, variously shaped mitochondria and cytoskeletal microfibrils. Their peripheral cytoplasm exhibited many vacuoles and a small number of these were autophagic lysosomes. In addition to the ultrastructural features described in the control fibroblasts, the EBD-R cells from the 6th passage contained remarkable numbers of strongly electron dense lysosomal bodies through their entire cytoplasm with very few empty vacuoles. It is speculated that the accumulation of these lysosomes may be connected with a primary metabolic cellular defect in the dermal fibroblasts of patients with EBD-R akin to that described in mucopolysaccharide storage diseases.