Salivary and serum IgA antigliadin antibodies in dermatitis herpetiformis

Serum IgA class antigliadin antibodies (IgA-AGA) are increased in untreated patients with coeliac disease and dermatitis herpetiformis (DH), and it has been suggested that salivary IgA-AGA measurements could be used as a non-invasive screening test for gluten-sensitive enteropathy. In the present study salivary and serum IgA-AGA were measured by an ELISA test in 10 untreated patients with DH. The results were compared to IgA-AGA levels in nine patients with DH on a long-term gluten-free diet (GFD) and in 20 healthy control subjects on an ordinary diet. The mean serum but not salivary IgA-AGA concentrations were significantly higher in the untreated than in the patients with DH on a long-term GFD. When the 10 untreated patients with DH adhered to a GFD for 3 months, the rash disappeared and the mean serum IgA-AGA decreased to normal levels, but no change was found in the mean salivary IgA-AGA concentration. These results show that serum but not salivary IgA-AGA measurements are suitable for monitoring GFD treatment in patients with DH. The discrepancy between the serum and salivary IgA-AGA concentrations suggests that systemic and salivary IgA-AGA responses are controlled separately.