Expression of keratins, epidermal proteins and inflammatory cells in superficial pemphigus dogs

Abstract

Superficial pemphigus in dogs is an autoimmune skin disorder. The disease is characterised by the binding of auto-antibodies to desmosomal molecules including desmocollin-1, a major auto-antigen in dogs. However, data on the expression of epidermal proteins in dogs are still limited. Therefore, the aim of this study was to investigate the keratins and epidermal proteins in dogs with superficial pemphigus using immunohistochemistry. Skin biopsies were performed on dogs with pemphigus foliaceus (n=10), pan-epidermal pustular pemphigus (n=4) and pemphigus erythematosus (n=1). Immunostaining for keratin 5 and keratin 10 showed a premature and discontinuous pattern in the suprabasal layers of all pemphigus skin samples compared to the control group (P<0.05). Filaggrin, desmocollin-1 and claudin-1, but not involucrin, were significantly reduced (P<0.05). Inflammatory cells markedly infiltrated in the dermis and the lower epidermis of all pemphigus skins. This is the first report that associates changes in the expression of keratin 5, keratin 10, filaggrin and claudin-1 with reduced desmocollin-1 expression and subsequent loss of the epidermal barrier in superficial pemphigus.