Identifying True Celiac Disease and Wheat Allergy in the Era of Fashion Driven Gluten-Free Diets.

BACKGROUND: Diagnosing both celiac disease (CD) and wheat allergy (WA) might be challenging due to the increasingly popular gluten-free diets. OBJECTIVES: This study investigates the value of anti-tissue transglutaminase IgA (tTGIgA) and wheat-specific IgE (WIgE), and identifies clinical and serological features associated with CD and WA. METHOD: Serological markers of autoimmunity and allergy along with medical charts of patients assessed for tTGIgA and WIgE between 2010 and 2016 were evaluated. RESULTS: During the last years, an increasing number of patients have been tested for tTGIgA, while the number of positive results decreased linearly. Among the 2,965 patients included, 128 patients showed at least once a positive tTGIgA. All patients with tTGIgA levels higher than the 12-fold upper normal limit had CD. The ratio of tTGIgA/total IgA did not perform better as a diagnostic test for CD compared to tTGIgA. tTGIgA and anti-nuclear antibodies were significantly associated. WA was only rarely investigated, particularly in adults. However, positive WIgE were found in nearly 50% of the cases. WIgE and tTGIgA values were negatively correlated. CONCLUSIONS: tTGIgA were increasingly tested, while the rate of positive results decreased in recent years, possibly reflecting the impact of current alimentary trends on clinical practice. Associated autoimmune disease was frequently found in CD. High levels of tTGIgA accurately predicted CD diagnosis. WA was rarely investigated and deserves more attention, in particular in children with atopic background. WA does not seem to be associated with CD.

Palmoplantar pustulosis and gluten sensitivity: a study of serum antibodies against gliadin and tissue transglutaminase, the duodenal mucosa and effects of gluten-free diet.

BACKGROUND: Palmoplantar pustulosis (PPP) is a chronic inflammatory disease affecting mainly smoking women. Some patients also have psoriasis. A subgroup of patients with psoriasis has been shown to have silent gluten sensitivity with relevance for their psoriasis. Nothing is known about gluten sensitivity in PPP. OBJECTIVES: To find out whether any patients with PPP are gluten-sensitive and whether this might be relevant for the PPP activity. PATIENTS AND METHODS: One hundred and twenty-three patients (113 women) with PPP participated. Screening for IgA antibodies against gliadin and tissue transglutaminase (tTG) was performed, the duodenal mucosa in patients with and without these antibodies was studied and the effect of a gluten-free diet (GFD) was followed up. RESULTS: Twenty-two patients (18%) had IgA antibodies against gliadin and nine of 94 (10%) against tTG. Twelve patients with antibodies and 11 without underwent gastro-duodenoscopy. Four displayed villous atrophy, whereas all other specimens were judged as essentially normal at routine staining. However, with immunohistochemistry, the numbers of CD3+ and CD8+ lymphocytes in the epithelium were found to be increased in patients with any type of antibody, although they were most numerous in those with both types of antibodies. Seven of 123 patients (6%) had coeliac disease (three previously diagnosed). Patients with antibodies who adhered to the GFD displayed total or nearly total clearance of the skin lesions and normalization of the antibody levels. CONCLUSIONS: Patients with PPP should be screened for antibodies against gliadin and tTG. Those with antibodies can be much improved on a GFD regardless of the degree of mucosal abnormalities.