Background: Treatment of celiac disease (CD) is based on the avoidance of gluten-containing food. However, it is not known whether trace amounts of gluten are harmful to treated patients. Objective: The objective was to establish the safety threshold of prolonged exposure to trace amounts of gluten (ie, contaminating gluten). Design: This was a multicenter, double-blind, placebo-controlled, randomized trial in 49 adults with biopsy-proven CD who were being treated with a gluten-free diet (GFD) for ≥2 y. The background daily gluten intake was maintained at <5 mg. After a baseline evaluation (t₀), patients were assigned to ingest daily for 90 d a capsule containing 0, 10, or 50 mg gluten. Clinical, serologic, and histologic evaluations of the small intestine were performed at t₀ and after the gluten microchallenge (t₁). Results: At t₀, the median villous height/crypt depth (Vh/Cd) in the small-intestinal mucosa was significantly lower and the intraepithelial lymphocyte (IEL) count (× 100 enterocytes) significantly higher in the CD patients (Vh/Cd: 2.20; 95% CI: 2.11, 2.89; IEL: 27; 95% CI: 23, 34) than in 20 non-CD control subjects (Vh/Cd: 2.87; 95% CI: 2.50, 3.09; IEL: 22; 95% CI: 18, 24). One patient (challenged with 10 mg gluten) developed a clinical relapse. At t₁, the percentage change in Vh/Cd was 9% (95% CI: 3%, 15%) in the placebo group (n = 13), −1% (−18%, 68%) in the 10-mg group (n = 13), and −20% (−22%, −13%) in the 50-mg group (n = 13). No significant differences in the IEL count were found between the 3 groups. Conclusions: The ingestion of contaminating gluten should be kept lower than 50 mg/d in the treatment of CD.

BACKGROUND: In selective IgA deficiency (IgAD), there is no reliable screening test for coeliac disease (CD). AIM: To evaluate the usefulness of IgG ₁ antiendomysium and IgG antitissue transglutaminase tests for CD diagnosis in IgAD. METHODS: IgA and IgG antigliadin antibodies (IgA- and IgG-AGA), IgA and IgG ₁ antiendomysium antibodies (IgA- and IgG ₁ -EMA), and IgA and IgG antitissue transglutaminase (IgA- and IgG-anti-tTG) were assayed in: (a) 20 untreated IgAD/CD patients; (b) 34 IgAD/CD patients on a strict gluten free diet (GFD); (c) 10 IgAD/CD patients not on a strict GFD; (d) 11 untreated CD patients without IgAD; (e) 10 healthy IgAD patients; and (f) 25 healthy controls. RESULTS: In all untreated IgAD/CD patients, IgG ₁ -EMA, IgG-anti-tTG, and IgG-AGA were positive whereas IgA antibodies against these antigens were negative. IgAD/CD patients on a strict GFD did not produce IgG-AGA or IgG ₁ -EMA but four of 34 produced IgG anti-tTG. IgAD/CD subjects not on a strict GFD produced IgG-AGA whereas 5/10 and 4/10 were IgG ₁ - EMA and IgG-anti-tTG negative, respectively. Untreated CD patients without IgAD were AGA (IgA and IgG), EMA (IgA and IgG ₁ ), and anti-tTG (IgA and IgG) positive. Healthy controls were AGA and EMA negative whereas two of 10 apparently healthy IgAD subjects and one of 25 healthy negative control were IgG-anti-tTG positive. CONCLUSIONS: Both IgG ₁ -EMA and IgG-anti-tTG tests appear to be useful for identification of IgAD/CD patients whereas they are less satisfactory for monitoring dietary compliance in these subjects. In addition, our findings seem to suggest that IgG-EMA autoantibodies produced by coeliac patients are mainly of the IgG ₁ subtype.

Replacement T4 dose in hypothyroid patients bearing both chronic autoimmune thyroiditis and atypical celiac disease (CD) has been analyzed. Replacement T4 dose has been analyzed in 35 hypothyroid patients with Hashimoto's thyroiditis (HT) and atypical CD, as defined by the American Gastroenterological Association. We have evaluated the ability of the same dose of T4 to reach target TSH in 21 patients before and during gluten-free diet (GFD). In the remaining 14 patients, noncompliant with GFD, we analyzed replacement T4 dose and compared it with that in a similar group consisting of 68 patients with hypothyroid HT but no evidence of celiac sprue or other conditions interfering with T4 absorption. In patients with isolated HT, the desired serum TSH (median=1.02 mU/liter) was reached in all patients after 5±2 months of treatment at a median T4 dose of 1.31 μg/kg·d. After a similar period and dose of T4, higher levels of TSH (median=4.20 mU/liter) were observed in patients with HT and CD. In 21 CD patients, target TSH (median TSH=1.25 mU/liter) has been attained after 11±3 months of GFD without increasing T4 dose (1.32 μg/kg·d). In the remaining 14 patients, who were noncompliant with GFD, target TSH has also been achieved but at a higher T4 dose (median=1.96 μg/kg·d; +49%; P=0.0002) than in hypothyroid patients without CD. Atypical CD increases the need for T4. The effect was reversed by GFD or by increasing T4 dose. Malabsorption of T4 may provide the opportunity to detect CD that was overlooked until the patients were put under T4 therapy.