The gluten-host interaction

Prevalence of coeliac disease in Italian patients affected by Addison's disease

OBJECTIVE

It is well known that coeliac disease is associated with autoimmune endocrine diseases, such as autoimmune thyroid disease and insulin-dependent diabetes mellitus. Recently, coeliac disease has been shown in approximately 10% of patients with autoimmune Addison's disease. Addison's disease is the most common cause of primary adrenocortical insufficiency and it shares several clinical features with coeliac disease. Although hyperpigmentation and hypotension are the most specific signs, gastrointestinal symptoms are common and can be the first complaints of the patients. The aim of our study was to investigate the prevalence of coeliac disease in Italian patients with Addison's disease.

MATERIAL AND METHODS

Seventeen consecutive patients affected by Addison's disease (14 F, mean age 53.9 years, range 26-79 years) were enrolled in the study. Eleven of them were affected by Addison's disease associated with autoimmune thyroid disease and/or insulin-dependent diabetes mellitus; the other 6 patients were suffering from isolated Addison's disease. Diagnosis had been performed at the age of 40.5 years (range 23-55). Steroid treatment had already been started in 16 of the patients. Endomysial antibodies were tested in all of them and a duodenal biopsy was taken in those found to be positive for antiendomysial antibody (EMA).

RESULTS

One out of 17 patients was found to be EMA positive. Duodenal biopsy confirmed the diagnosis of coeliac disease by showing subtotal villous atrophy.

CONCLUSIONS

Although we studied only a small sample, our preliminary results confirmed that Addison's disease is associated with coeliac disease, being present in 5.9% of patients with Addison's disease. Since the symptoms can be similar and treatment of Addison's disease can mask coeliac disease, this association should always be actively investigated.

Defining gluten refractory enteropathy

OBJECTIVE

The diagnosis of coeliac disease (CD) is based on the responsiveness of the enteropathy to a gluten-free diet (GFD). This implies that terms such as 'non-responsive CD' and 'refractory CD' are almost paradoxical. In spite of this, these terms are commonly used in the literature, often with different and confusing meanings.

METHODS

On the basis of both a review of the literature and our clinical experience, we propose the following classification. A condition characterized by a refractory enteropathy, not due to lymphoma, ulcerative jejunoileitis or collagenous sprue, but in which gluten sensitivity has been shown previously or could be shown while the patients were on an immunosuppressive therapy should be indicated as refractory CD. Those patients in whom gluten sensitivity can be excluded should be considered to be affected by non-coeliac refractory sprue. Finally, patients in whom the presence of CD cannot be either confirmed or excluded should be considered to be affected by undefined sprue.

RESULTS

Twenty-four certain refractory patients are described in the literature. The data suggest a diagnosis of refractory CD in 13 patients, non-coeliac refractory sprue in three patients, and undefined sprue in eight patients.

CONCLUSIONS

We define refractory CD as a form of CD that no longer responds to a GFD. Non-coeliac refractory sprue is a condition unrelated to CD. It could be either an independent condition or a common end point of different enteropathies.

IgA-gliadin antibodies, IgA-containing circulating immune complexes, and IgA glomerular deposits in wasting marmoset syndrome

BACKGROUND

Marmosets in captivity are highly susceptible to wasting marmoset syndrome (WMS), the aetiology of which is still not fully determined.

METHODS

The level of IgA-gliadin antibodies (IgA-AGA), of IgA-containing circulating immune complexes (IgA-CIC), and the degree of glomerular IgA deposits were compared between marmosets suffering from WMS and animals not affected by the disorder.

RESULTS

Both IgA-AGA and IgA-CIC were demonstrable in all groups of monkeys investigated. IgA-AGA and IgA-CIC were significantly higher in monkeys with WMS than in non-affected animals. There was a significant correlation between the glomerular IgA-deposition and titre of IgA-AGA. The group of marmosets strongly positive for glomerular IgA deposits comprised significantly more animals suffering from WMS than the group without deposits. In the diet of the animals a considerable amount of gliadin-like cereal proteins was assayed.

CONCLUSIONS

There are several parallels between the human disorders (coeliac disease and IgA-nephropathy/Berger's disease) and the changes observed in WMS. It should be further investigated if WMS in marmosets is a suitable animal model for both human diseases.

Cutting Edge: Selective Deamidation by Tissue Transglutaminase Strongly Enhances Gliadin-Specific T Cell Reactivity

Celiac disease (CD) is caused by gluten ingestion in susceptible individuals. Tissue transglutaminase (tTG)-specific Abs are characteristic of CD, and increased tTG activity has been observed in the jejunal biopsies of patients. Here we demonstrate that tTG selectively deamidates gluten peptides, which results in strongly enhanced T cell-stimulatory activity. To our knowledge, this is the first example of an enzymatic modification of a food protein that affects T cell recognition. Moreover, these modifications may lead to the amplification of gluten-specific T cell responses in the gut and consequently may be important for the development of CD.