Reintroduction Of Dietary Gluten Research Articles

Recognition of Epidermal Transglutaminase by IgA and Tissue Transglutaminase 2 Antibodies in a Rare Case of <em>Rhesus</em> Dermatitis

Tissue transglutaminase 2 (tTG2) is an intestinal digestive enzyme which deamidates already partially digested dietary gluten e.g. gliadin peptides. In genetically predisposed individuals, tTG2 triggers autoimmune responses that are characterized by the production of tTG2 antibodies and their direct deposition into small intestinal wall 1,2. The presence of such antibodies constitutes one of the major hallmarks of the celiac disease (CD). Epidermal transglutaminase (eTG) is another member of the transglutaminase family that can also function as an autoantigen in a small minority of CD patients. In these relatively rare cases, eTG triggers an autoimmune reaction (a skin rash) clinically known as dermatitis herpetiformis (DH). Although the exact mechanism of CD and DH pathogenesis is not well understood, it is known that tTG2 and eTG share antigenic epitopes that can be recognized by serum antibodies from both CD and DH patients 3,4. In this study, the confocal microscopy examination of biopsy samples from skin lesions of two rhesus macaques (Macaca mulatta) with dermatitis (Table 1, Fig. 1 and 2) was used to study the affected tissues. In one animal (EM96) a spectral overlap of IgA and tTG2 antibodies (Fig. 3) was demonstrated. The presence of double-positive tTG2+IgA+ cells was focused in the deep epidermis, around the dermal papillae. This is consistent with lesions described in DH patients 3. When EM96 was placed on a gluten-free diet, the dermatitis, as well as tTG2+IgA+ deposits disappeared and were no longer detectable (Figs. 1-3). Dermatitis reappeared however, based on re-introduction of dietary gluten in EM96 (not shown). In other macaques including animal with unrelated dermatitis, the tTG2+IgA+ deposits were not detected. Gluten-free diet-dependent remission of dermatitis in EM96 together with presence of tTG2+IgA+ cells in its skin suggest an autoimmune, DH-like mechanism for the development of this condition. This is the first report of DH-like dermatitis in any non-human primate.

Recognition of epidermal transglutaminase by IgA and tissue transglutaminase 2 antibodies in a rare case of Rhesus dermatitis.

Tissue transglutaminase 2 (tTG2) is an intestinal digestive enzyme which deamidates already partially digested dietary gluten e.g. gliadin peptides. In genetically predisposed individuals, tTG2 triggers autoimmune responses that are characterized by the production of tTG2 antibodies and their direct deposition into small intestinal wall. The presence of such antibodies constitutes one of the major hallmarks of the celiac disease (CD). Epidermal transglutaminase (eTG) is another member of the transglutaminase family that can also function as an autoantigen in a small minority of CD patients. In these relatively rare cases, eTG triggers an autoimmune reaction (a skin rash) clinically known as dermatitis herpetiformis (DH). Although the exact mechanism of CD and DH pathogenesis is not well understood, it is known that tTG2 and eTG share antigenic epitopes that can be recognized by serum antibodies from both CD and DH patients. In this study, the confocal microscopy examination of biopsy samples from skin lesions of two rhesus macaques (Macaca mulatta) with dermatitis (Table 1, Fig. 1 and 2) was used to study the affected tissues. In one animal (EM96) a spectral overlap of IgA and tTG2 antibodies (Fig. 3) was demonstrated. The presence of double-positive tTG2+IgA+ cells was focused in the deep epidermis, around the dermal papillae. This is consistent with lesions described in DH patients. When EM96 was placed on a gluten-free diet, the dermatitis, as well as tTG2+IgA+ deposits disappeared and were no longer detectable (Figs. 1-3). Dermatitis reappeared however, based on re-introduction of dietary gluten in EM96 (not shown). In other macaques including animal with unrelated dermatitis, the tTG2+IgA+ deposits were not detected. Gluten-free diet-dependent remission of dermatitis in EM96 together with presence of tTG2+IgA+ cells in its skin suggest an autoimmune, DH-like mechanism for the development of this condition. This is the first report of DH-like dermatitis in any non-human primate.

A Non-Human Primate Model for Gluten Sensitivity

Background and AimsGluten sensitivity is widespread among humans. For example, in celiac disease patients, an inflammatory response to dietary gluten leads to enteropathy, malabsorption, circulating antibodies against gluten and transglutaminase 2, and clinical symptoms such as diarrhea. There is a growing need in fundamental and translational research for animal models that exhibit aspects of human gluten sensitivity.MethodsUsing ELISA-based antibody assays, we screened a population of captive rhesus macaques with chronic diarrhea of non-infectious origin to estimate the incidence of gluten sensitivity. A selected animal with elevated anti-gliadin antibodies and a matched control were extensively studied through alternating periods of gluten-free diet and gluten challenge. Blinded clinical and histological evaluations were conducted to seek evidence for gluten sensitivity.ResultsWhen fed with a gluten-containing diet, gluten-sensitive macaques showed signs and symptoms of celiac disease including chronic diarrhea, malabsorptive steatorrhea, intestinal lesions and anti-gliadin antibodies. A gluten-free diet reversed these clinical, histological and serological features, while reintroduction of dietary gluten caused rapid relapse.ConclusionsGluten-sensitive rhesus macaques may be an attractive resource for investigating both the pathogenesis and the treatment of celiac disease.

Clinical response to gluten withdrawal is not an indicator of coeliac disease

Objective. Although the diagnosis of coeliac disease requires specific histological and serological findings, patients considered to be affected by coeliac disease only on the basis of clinical improvement after gluten withdrawal are commonly referred to our outpatient clinic. The objective of this study was to investigate whether the clinical response of gastrointestinal symptoms to gluten withdrawal and subsequent dietary re-introduction could be an indicator of the presence of coeliac disease. Material and methods. From December 1998 to January 2007, 180 patients on a gluten-free diet because of a diagnosis of coeliac disease not based on proper diagnostic criteria came to our out-patient clinic. In 112 of these patients, gluten was re-introduced into their diet. Subsequent duodenal biopsies and endomysial antibodies confirmed the diagnosis of coeliac disease in 51 of them. The relationship between improvement/worsening of symptoms and withdrawal/re-introduction of dietary gluten was analysed. Results. Gastrointestinal symptoms improved in 64.7% of coeliac patients and 75.0% of non-coeliac patients after gluten withdrawal (χ2 test, p=NS). Gluten re-introduction was followed by clinical exacerbation in 71.4% of coeliac patients and 54.2% of non-coeliac patients (χ2 test, p=NS). The positive predictive value for clinical improvement after gluten withdrawal was 36%; the positive predictive value for clinical exacerbation after gluten re-introduction was 28%. Conclusions. Clinical response to either withdrawal or re-introduction of dietary gluten has no role in the diagnosis of coeliac disease.

Long-term remission in patients with dermatitis herpetiformis on a normal diet.

A life-long gluten-free diet is the treatment of choice for dermatitis herpetiformis, which is considered to be coeliac disease of the skin. To investigate the effects on long-term remission of dermatitis herpetiformis in patients who underwent a gluten challenge and subsequently reintroduced dietary gluten. We studied 38 patients (14 male and 24 female) with biopsy-confirmed dermatitis herpetiformis. They had followed a gluten-free diet for a mean of 8 years, achieving clinical remission and intestinal normalization. The patients were asked to reintroduce gluten in their diet and agreed to undergo skin and intestinal biopsies during the follow-up. Of the 38 patients abandoning a gluten-free diet, 31 reported the onset of rash within an average of 2 months. Seven subjects (three males, mean age 15 years at challenge) experienced no clinical or histological relapses (median follow-up 12 years), and lost IgA immunoglobulin from the skin. The two series of patients differed in terms of age at diagnosis (mean age: 26.6 vs. 6 years), the use of dapsone (one of 31 vs. four of seven) and adherence to the gluten-free diet (strict compliance in 26 of 31 vs. none of seven). Our data suggest that the ingestion of small doses of gluten in childhood and/or the use of an anti-inflammatory drug may modify the immunological response inducing immune tolerance. We report long-term clinical and histological remissions in seven patients with dermatitis herpetiformis after the reintroduction of dietary gluten.

6 Coeliac disease in childhood

Coeliac disease usually presents in infancy or early childhood with diarrhoea, vomiting and interference with weight gain and growth. Withdrawal of dietary gluten is followed by resolution of the symptoms and signs and restoration of normal weight gain and growth; the characteristic subtotal villous atrophy of the jejunal mucosa also recovers. Later re-introduction of dietary gluten will lead to a return of the jejunal mucosal abnormality in the majority and to clinical relapse in many but not all. The severity and timing of both are variable and 5% of children initially considered on clinical, biopsy and gluten response evidence to have coeliac disease appear to develop permanent tolerance to gluten, although mucosal relapse may occur years after the re-introduction of dietary gluten in a minority, emphasizing the need for long-term follow-up. Although a diagnostic and subsequent follow-up jejunal biopsy are necessary to confirm the diagnosis, anti-gliadin IgA and IgG, anti-reticulin and anti-endomysium antibodies are now almost totally reliable in identifying children who have coeliac disease and are valuable in monitoring the adequacy of gluten withdrawal. Dietary compliance is frequently poor and regular supervision by a paediatric dietitian is needed; indeed, lifelong supervision to ensure gluten withdrawal is essential to reduce the chance of developing later gastrointestinal malignancy.

Immunoglobulins in the jejunal mucosa in adult coeliac disease and dermatitis herpetiformis after the reintroduction of dietary gluten.

Cells containing immunoglobulin (IgA, IgG, IgM) have been measured and the distribution of extracellular and epithelial cell immunoglobulin assessed in treated patients with adult coeliac disease (ACD) and dermatitis herpetiformis (DH) before and after gluten was reintroduced to the diet. Patients with ACD and DH frequently had IgM and IgG cells above the normal range even before re-exposure to gluten, although the range of IgA cells was normal. In both diseases IgA and IgM cells increased after gluten with a proportionally greater rise in the latter, so that numbers of IgM cells, but not of IgA, exceeded the control range in all but one patient. There were increased quantities of IgA and IgM extracellularly in the lamina propria and in epithelial cells after challenge with gluten. Third component of complement was also found in some biopsies after re-exposure to gluten. These findings support the suggestion that gluten induces a humoral immunological response within the small intestinal mucosa and that both IgA and IgM systems are involved.

Cellular infiltrate of the jejunum after re-introduction of dietary gluten in children with treated coeliac disease.

Jejunal lamina propria plasma cells and eosinophils and intraepithelial lymphocytes were raised in coeliac children on gluten-containing diets, but only intraepithelial lymphocytes were increased in patients on gluten-free diets. In contrast, lamina propria lymphocytes were reduced in children with coeliad disease on gluten-containing diets but were normal in paitents on gluten-free diets. In children with coeliac disease who were studied serially, lamina propria plasma cells and eosinophils and intraepithelial lymphocytes increased, and lamina propria lymphocytes decreased, within three months of the reintroduction of gluten to the diet. These observations are essentially similar to those made in the adult form of the disease and suggest that more than one type of immunological reaction is involved in the pathogenesis of the jejunal lesion.

Immunological phenomena in the jejunum and serum after reintroduction of dietary gluten in children with treated coeliac disease.

Jejunal mucosal immunoglobulin-containing cells of all three major classes (IgA, IgM, IgG) were increased in coeliac children on gluten-containing diets but only IgM cell numbers were raised in those on gluten-free diets. Patients with subtotal villous atrophy had greater numbers of immunoglobulin-containing cells than patients with normal mucosa. In previously treated patients studied before and after three months on a gluten-containing diet ther was an increase in all three classes of cell, IgM containing cells showing the greatest proportional rise. Basement membrane staining with anti-IgA serum occurred in coeliacs and was most intense in untreated patients. Apart from one patient with very low levels of serum IgA, serum immunoglobulins did not differ from normal. However, after reintroduction of gluten to the diet a significant fall in serum IgM concentrations occurred compared with levels in the same patients while on gluten-free diets. It seems probable that both IgA and IgM systems are important in the immunopathogenesis of the small intestinal lesion of childhood coeliac disease.

The cellular infiltrate of the jejunum in adult coeliac disease and dermatitis herpetiformis following the reintroduction of dietary gluten.

The cellular infiltrate of the jejunal mucosa has been studied in patients with both treated and untreated adult coeliac disease and dermatitis herpetiformis and serially in treated patients before and after the reintroduction of gluten to the diet. In adult coeliac disease and dermatitis herpetiformis the jejunal mucosa showed similar abnormalities of the cellular infiltrate which was characterized by an increase in intraepithelial lymphocytes and lamina propria plasma cells and eosinophils, with the greatest numbers of cells occurring in untreated patients. At 24-48 hours following a single 25-g gluten challenge there was an increase in lamina propria plasma cells, lymphocytes and eosinophils and intraepithelial lymphocytes. This rise was sustained after seven days on a gluten-containing diet for all of these cell groups except lamina propria lymphocytes. These responses were essentially similar in both adult coeliac disease and in those dermatitis herpetiformis patients who had jejunal lesions before treatment. In dermatitis herpetiformis patients with normal jejunal morphology on a normal diet there was an upward trend in lamina propria plasma cells and intraepithelial lymphocytes within one to three weeks of taking extra dietary gluten. These results are compatible with the view that more than one immunological mechanism may be responsible for the pathogenesis of the jejunal lesion of coeliac disease and dermatitis herpetiformis.

Limitations of xylose tolerance test as a screening procedure in childhood coeliac disease.

The usefulness of the xylose tolerance test as a screening procedure for coeliac disease has been reassessed in 54 children with suspected coeliac disease. 5- and 24-hour urinary excretion rates of xylose were of no value in discriminating between patients with and without coeliac disease; similarly, the 3-hour blood xylose concentration was nondiscriminatory. Three (15-8%) patients with subtotal villous atrophy and 8 (61-5%) with partial villous atrophy due to coeliac disease had one-hour blood xylose values which fell within the normal range. The effect of withdrawal or reintroduction of dietary gluten on sequential one-hour blood xylose levels was variable and generally unhelpful in predicting those patients who developed gluten-induced mucosal changes. The results of the present study emphasize the serious limitations of the xylose tolerance test as a screening procedure in childhood coeliac disease. It is recommended that the use of the urinary xylose test should be abandoned in the paediatric population. A normal one-hour blood xylose value does not exclude a diagnosis of coeliac disease even in young children who have never received a gluten-free diet. A clinical suspicion of coeliac disease remains the most important single factor in deciding whether to preform a jejunal biopsy.

Plasma food antibodies during withdrawal and reintroduction of dietary gluten in coeliac disease.

Plasma food antibodies during withdrawal and reintroduction of dietary gluten in coeliac disease.

Plasma food antibodies and blood folate levels during the withdrawal and reintroduction of dietary gluten in children with coeliac disease.

Plasma food antibodies and blood folate levels during the withdrawal and reintroduction of dietary gluten in children with coeliac disease.