Are anti-epidermal transglutaminase (eTG) antibodies titre correlated with dermatitis herpetiformis lesions during the disease follow-up?

BACKGROUND: Dermatitis herpetiformis (DH) is characterized by the presence of anti-tissue transglutaminase (tTG) IgA antibodies in patient sera. In 2002, anti-epidermal transglutaminase (eTG) antibodies have been identified in DH patients. Nowadays, their role is still controversial.

AIM: To evaluate any association between presence/absence of anti-eTG antibodies and cutaneous manifestations during the follow-up.

METHODS: Anti-eTG and anti-tTG antibodies from 13 patients on gluten-free diet (GFD) were studied during follow-up on ELISA. Cutaneous manifestations baseline differences among age, gender, anti-eTG IgA, anti-tTG IgA, and treatment groups were tested by the Wilcoxon Rank Sum and Fisher's exact test. In order to investigate the associations of cutaneous manifestations with age, gender, anti-eTG IgA, anti-tTG IgA, and treatment groups the Mixed-Effects (ME) model was performed. To test whether the cutaneous manifestations in treatment groups were different according to the anti-eTG levels, an Exploratory Interaction Analysis was carried out using the ME Model.

RESULTS: Seven patients (53.85%) had an anti-eTG value greater than 22 AU/ml, while six (46.15%) were classified as anti-eTG value <22 AU/ml. A significant correlation between anti-eTG antibodies and cutaneous manifestations was observed. No significant cutaneous manifestations differences existed in treatment groups according to the anti-eTG antibodies levels. Anti-tTG antibodies resulted negative in every patient serum.

CONCLUSIONS: Anti-eTG antibodies persist much longer after the elimination of gluten from the patients diet compared to anti-tTG antibodies and seem to be a valid marker for monitoring the disease during the follow-up.