Celiac/coeliac disease and Dermatitis herpetiformis Duhring, the two recognized forms of gluten sensitive enteropathy (GSE), are small bowel malabsorption disorders occuring both in children and adults. They are mainly characterized by flat mucosa because of chronic inflammation or subtotal villous atrophy, associated with lymphocytic infiltration and circulating antibodies (IgA and IgG) to Gliadin (AGA), a dietary water-insoluble wheat gluten protein, and endomysium (EMA), a component of smooth muscle connective tissue. Patients with celiac disease may suffer from diarrhea, anaemia, fatigue, and muscoloskeletal disorders. Dermatitis herpetiformis is a skin disease which is associated with celiac disease. All GSE patients have an increased risk of gastrointestinal malignancy, infertility and osteoporosis. But a gluten-free diet can easily control GSE and the associated risks and is therefore of special interest. IgA in the gut is formed predominantly as secretory IgA (sIgA), which is secreted in the lumen of the intestine and could easily be detected in faeces because of its stability.