Epidermal transglutaminase (TGase 3) Is the autoantigen of dermatitis herpetiformis

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Description/Abstract

Gluten sensitivity typically presents as celiac disease, a common chronic small intestinal disorder.
However, in certain individuals it is associated with dermatitis herpetiformis, a blistering
skin disease characterized by granular IgA deposits in the papillary dermis. While tissue transglutaminase
has been implicated as the major autoantigen of gluten sensitive disease, there has
been no explanation as to why this condition appears in two distinct forms. Here we show that
while sera from patients with either form of gluten sensitive disease react both with tissue transglutaminase
and the related enzyme epidermal (type 3) transglutaminase, antibodies in patients
having dermatitis herpetiformis show a markedly higher avidity for epidermal transglutaminase.
Further, these patients have an antibody population specific for this enzyme. We also show that
the IgA precipitates in the papillary dermis of patients with dermatitis herpetiformis, the defining
signs of the disease, contain epidermal transglutaminase, but not tissue transglutaminase or keratinocyte
transglutaminase. These findings demonstrate that epidermal transglutaminase, rather
than tissue transglutaminase, is the dominant autoantigen in dermatitis herpetiformis and explain
why skin symptoms appear in a proportion of patients having gluten sensitive disease.