Autophagy in malnutrition-associated dermatoses.

Malnutrition-associated dermatoses including necrolytic migratory erythema (NME) and pellagra share common clinicopathological features; in particular, necrolytic changes in the upper epidermis. Here, we report the involvement of autophagy in the development of necrolysis in three patients with malnutrition-associated dermatoses. First, we examined an autophagy-specific molecule, microtubule-associated protein light chain 3 (LC3), using a monoclonal antibody. LC3 was strongly expressed in the granular layers of the active border, and less intensely observed in the perilesional areas. Little LC3 staining or only background levels were observed in control skin diseases including atopic dermatitis (n = 4), psoriasis vulgaris (n = 3), basal cell carcinoma with amyloid deposits (n = 3) and squamous cell carcinoma (n = 3). Electron microscopic observations revealed the presence of autophagosome-like structures in the necrolytic areas. No apoptotic signals were observed in the necrolytic lesion using the terminal deoxynucleotidyl transferase dUTP nick end labeling method. Epidermal Langerhans cells determined by anti-CD1a antibody were markedly decreased in number. Our observations suggest the possibility that malnutrition-associated necrolysis, as exemplified by NME and pellagra, may be induced by autophagy.