Neo-epitope tissue transglutaminase autoantibodies as a biomarker of the gluten sensitive skin disease--dermatitis herpetiformis.

The deamidated gliadin peptides (DGP) cross linked to human tissue transglutaminase (tTg) comprises a novel neo-epitope structure (Neo-tTg) for serological screening of celiac disease (CD). Our aim is to verify anti-Neo-tTg IgA and IgG in adults with dermatitis herpetiformis (DH). Multi-centric retrospective evaluation of the IgA/G autoantibodies in sera of DH patients on a regular diet (n=40) and a gluten restricted diet (GRD, n=53) and control adults with autoimmune skin diseases (n=107) by ELISA. The sensitivities of Celicheck Neo IgA/G (76%, 95% CI 67-84%) and the Neo tTg-A (85%, 95% CI 70-97%) ELISA were significantly greater than that of tTg-A (56%, 95% CI 46-67%), eTg-A (62%, 95% CI 52-72%), DGP-A (55%, 95% CI 55-65%), DGP-G (61%, 95% CI 51-71%), Glia-A (55%, 95% CI 45-65%) and Glia-G (56%, 95% CI 46-66%) ELISA. The specificities of all 8 ELISA were in the range of 90-100%. The area under the curve (AUC) of receiver operator characteristic curve (ROC) for the two Neo-tTg ELISA (0.863 and 0.949) were higher than the AUCs for ROCs of tTg, DGP and eTG ELISA (range between 0.657 and 0.783). The autoantibody levels of DH patients on a normal diet were significantly higher than those on GRD in the Celicheck Neo IgA/IgG, NeotTg-A; tTg-A and the eTg-A; ELISA (p<0.01) and of no significance in the DGP and Gliadin ELISA. Neo-epitope IgA autoantibodies represent a new and sensitive serological marker of DH.