The utility of tissue and epidermal transglutaminase immunohistochemistry in dermatitis herpetiformis

Abstract

Dermatitis herpetiformis (DH), also known as Duhring-Brocq dermatitis, is an autoimmune, chronic subepidermal blistering disorder characterized by an intensely pruritic, papulovesicular eruption. It is linked to gluten sensitivity and considered to be a cutaneous manifestation of celiac disease. It has been demonstrated that sera from most patients with DH demonstrate autoantibodies against epidermal transglutaminase (eTG) and tissue transglutaminase (tTG). Therefore, the aim of the study was to evaluate the diagnostic utility of eTG and tTG immunohistochemistry in identifying patients with DH. A total of 15 skin biopsies from patients with an established diagnosis of DH confirmed by histopathology and direct immunofluorescence (DIF) studies were evaluated. Six cases were used as controls in which the clinical differential included DH and were found to be nondiagnostic by both histopathology and DIF evaluations. Eight (55%) of the DH cases were positive for eTG expression, while none of the controls showed any immunoreactivity (P = 0.0456). All 15 (100%) DH cases showed faint granular staining for tTG in the epidermal basal layers with similar results in all 6 (100%) control cases. Our study indicates eTG immunohistochemistry may aid in identifying patients with DH, with a diagnostic sensitivity and specificity of 55% and 100%, respectively. tTG does not appear to be a useful immunomarker in this setting.