Serum reactivity in dermatitis herpetiformis: an international multicenter study

Abstract Background Dermatitis herpetiformis (DH) is a rare gluten-induced skin disorder characterized predominantly by IgA autoantibodies against endomysium, tissue transglutaminase (TG2/tTG), epidermal transglutaminase (TG3/eTG), and deamidated gliadin. To date, circulating autoantibody reactivity has not been systematically described. Objective Characterization of serum reactivities in DH. Methods This multicenter international study analyzed sera from 242 DH patients taken at the time of initial diagnosis. DH-specific IgA and IgG serum autoantibodies were analyzed by indirect immunofluorescence (IF) on monkey esophagus, and by enzyme-linked immune sorbent assay (ELISA) based on recombinant TG2/tTG, TG3/eTG, and deamidated gliadin (GAF3X). Results IgA indirect IF microscopy on monkey esophagus revealed the highest reactivity (84.3%; specificity 100%) followed by IgA TG2/tTG ELISA (78.5%, 99.0%), IgA TG3/eTG ELISA (72.7%, 95.0%), and IgA GAF3X ELISA (69.0%, 98.5%). Conclusion Serum IgA and IgG autoantibodies against endomysium, TG2/tTG, TG3/eTG, and deamidated gliadin are highly prevalent in DH. Indirect IF microscopy on monkey esophagus (IgA) provides the highest diagnostic accuracy that can be further enhanced by 3.5% when combined with IgA TG2/tTG ELISA.