Evaluation of a Bi-Analyte Immunoblot as a Useful Tool for Diagnosing Dermatitis Herpetiformis

Primate liver tissue substrate in indirect immunofluorescence diagnostics for patients with dermatitis herpetiformis and celiac disease

Introduction

Dermatitis herpetiformis (DH) is a rare autoimmune, polymorphous blistering disorder, characterized by severe itch or burning sensation, which represents the cutaneous manifestation of celiac disease (CD). The current estimation of DH versus CD is around 1:8 and the affected individuals have a genetic predisposition. Pathogenetically, IgA autoantibodies against the epidermal transglutaminase, an essential constituent of the epidermis, cause DH and are reported to develop through cross-reaction with the tissue transglutaminase, with IgA auto-antibodies causing CD. Immunofluorescence techniques allow for a rapid diagnostics of the disease using patient sera. Evaluation of IgA endomysial deposition with indirect immunofluorescence on monkey oesophagus is highly specific, but moderately sensitive, with some operator-dependent variability. Recently, indirect immunofluorescence with monkey liver as a substrate has been proposed as an alternative, well-functioning diagnostic approach with higher sensitivity in CD.

Methods

The objective of our study was to evaluate whether monkey oesophagus or liver tissue shows advantage for diagnostics in patients with DH, compared to CD. To that end, sera of 103 patients with DH (n=16), CD (n=67) and 20 controls ere compared by 4 blinded experienced raters.

Results

For DH, we found a sensitivity of 94.2% for monkey liver (ML) compared to 96.2% in monkey oesophagus (ME), while specificity in ML was superior (91.6% versus 75%) to ME. In CD, ML had a sensitivity of 76.9% (ME 89.1%) and specificity of 98.3% (ME 94.1%).

Discussion

Our data show that ML substrate is well suitable for DH diagnostics.

Dermatitis Herpetiformis: An Update on Diagnosis, Disease Monitoring, and Management

Dermatitis herpetiformis (DH), Duhring disease, is caused by gluten sensitivity and affects 11.2 to 75.3 per 100,000 people in the United States and Europe with an incidence of 0.4 to 3.5 per 100,000 people per year. DH is characterized by a symmetrical blistering rash on the extensor surfaces with severe pruritus. The diagnosis continues to be made primarily by pathognomonic findings on histopathology, especially direct immunofluorescence (DIF). Recently, anti-epidermal transglutaminase (TG3) antibodies have shown to be a primary diagnostic serology, while anti-tissue transglutaminase (TG2) and other autoantibodies may be used to support the diagnosis and for disease monitoring. Newly diagnosed patients with DH should be screened and assessed for associated diseases and complications. A gluten-free diet (GFD) and dapsone are still mainstays of treatment, but other medications may be necessary for recalcitrant cases. Well-controlled DH patients, managed by a dermatologist, a gastroenterologist, and a dietician, have an excellent prognosis. Our review comprehensively details the current diagnostic methods, as well as methods used to monitor its disease course. We also describe both the traditional and novel management options reported in the literature.