In patients with dermatitis herpetiformis distribution of transglutaminase in cutaneous tissue does not differ from controls

BACKGROUND: Dermatitis herpetiformis may be regarded as the cutaneous counterpart of coeliac disease. These conditions are related to the ingestion of gluten and both are characterised by circulating antibodies against tissue transglutaminase. AIMS: To study the distribution of tissue transglutaminase in the skin of dermatitis herpetiformis patients and controls, and to investigate whether the dermal IgA deposits, diagnostic for dermatitis herpetiformis, are related to tissue transglutaminase expression in the skin. METHODS: A series of 11 patients with dermatitis herpetiformis had a 4 mm punch biopsy taken from the uninvolved perilesional skin. A group of 16 controls, undergoing surgical removal of benign nevi, gave perilesional skin. Biopsies were covered with OCT and frozen at -80 degrees C. After washing, skin biopsy sections were incubated with an IgG anti-tissue transglutaminase mouse monoclonal antibody. After washing, sections were incubated with anti-mouse IgG. RESULTS: The anti-tissue transglutaminase monoclonal antibody specifically recognised the basal epidermal cells. This staining was no different between patients and controls. CONCLUSION: Our results suggest that tissue transglutaminase can be recognised in the basal epidermal layer both of patients with dermatitis herpetiformis and controls. Since this distribution does not correspond to the distribution of dermal IgA deposits, it is concluded that dermatitis herpetiformis dermal IgA deposits are not due to antibodies directed against cutaneous tissue transglutaminase.