Serum antibodies to gliadin and small-intestinal morphology in dermatitis herpetiformis. A controlled clinical study of the effect of treatment with a gluten-free diet.

Serum gliadin antibodies of the IgA and IgG classes were determined by the diffusion-in-gel enzyme-linked immunosorbent assay in 41 patients with dermatitis herpetiformis before treatment with a gluten-free diet. Increased gliadin antibody levels were found more frequently in patients with subtotal villous atrophy (9 out of 17 patients, or 53%; p less than 0.05) than in patients with partial villous atrophy (2 out of 13 patients, or 15%) or normal villous appearance (2 out of 10 patients, or 20%). The gliadin antibody levels were negatively correlated with the urinary xylose excretion (r = -0.40, p less than 0.02 for the IgA class and r = -0.64, p less than 0.001 for the IgG class). Intestinal morphology improved and mean gliadin antibody levels of the IgA and IgG classes decreased during treatment with a gluten-free diet for 16-36 months (mean, 20 months) (p less than 0.005, n = 26), whereas no significant changes of the gliadin antibody levels or the small-intestinal morphology were observed in the other 15 patients, who continued on a non-restricted diet for 17-35 months (mean, 20 months). Thus, gliadin antibody levels in sera from patients with dermatitis herpetiformis seem to be correlated with the severity of the intestinal disease. However, all patients with villous atrophy are not detected by determination of serum gliadin antibodies.

Secretin release in coeliac disease. Plasma secretin concentration and bicarbonate output to the duodenum after intraduodenal acid infusion in coeliac patients before and after treatment.

Infusion of 40 ml 0.1 mol/l HCl into the duodenum in eight untreated coeliac patients was followed by an increase of the plasma immunoreactive secretin (IRS) concentration from 1.6 +/- 0.2 pmol/l to a peak level of 2.4 +/- 0.3 pmol/l (p less than 0.05). After treatment with a gluten-free diet, the same patients showed an increase from 1.4 +/- 0.3 pmol/l to a peak level of 5.5 +/- 0.9 pmol/l after intraduodenal acid infusion, which was significantly higher than before treatment (p less than 0.01). In control subjects, intraduodenal acid infusion was followed by an increase from 1.4 +/- 0.2 pmol/l to 6.7 +/- 1.1 pmol/l, which was significantly higher than in untreated coeliac disease (p less than 0.01) but did not differ from what was found in treated coeliac patients. Significant differences in pH, volume, or bicarbonate content of the duodenal aspirates or the basal IRS levels were not found.

Evaluation of gliadin antibodies for detection of coeliac disease.

To evaluate assay of gliadin antibodies of different immunoglobulin classes as a test for detection of coeliac disease, we analysed sera from 36 adult patients and 8 children with coeliac disease, 62 patients with other gastrointestinal diseases, and 124 blood donors with diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA). Depending on the choice of reference levels for gliadin antibodies of the IgA and IgG classes, respectively, we found a diagnostic sensitivity for coeliac disease of 93-86% and a diagnostic specificity of 95-100%. Determination of gliadin antibodies by DIG-ELISA can thus be used as a test for detection of coeliac disease and selection of patients for small-intestinal biopsy.