Coeliac disease. Some still controversial aspects

Emergence of an adaptive immune paradigm to explain celiac disease: a perspective on new evidence and implications for future interventions and diagnosis

INTRODUCTION

Recent patient studies have shown that gluten-free diet is less effective in treating celiac disease than previously believed, and additionally patients remain vulnerable to gluten-induced acute symptoms and systemic cytokine release. Safe and effective pharmacological adjuncts to gluten-free diet are in preclinical and clinical development. Clear understanding of the pathogenesis of celiac disease is critical for drug target identification, establishing efficacy endpoints and to develop non-invasive biomarkers suitable to monitor and potentially diagnose celiac disease.

AREAS COVERED

The role and clinical effects of CD4+ T cells directed against deamidated gluten in the context of an "adaptive immune paradigm" are reviewed. Alternative hypotheses of gluten toxicity are discussed and contrasted. In the context of recent patient studies, implications of the adaptive immune paradigm for future strategies to prevent, diagnose, and treat celiac disease are outlined.

EXPERT OPINION

Effective therapeutics for celiac disease are likely to be approved and necessitate a variety of new clinical instruments and tests to stratify patient need, monitor remission, and confirm diagnosis in uncertain cases. Sensitive assessments of CD4+ T cells specific for deamidated gluten are likely to play a central role in clinical management, and to facilitate research and pharmaceutical development.

Does breast-feeding affect the risk for coeliac disease?

Coeliac disease, or permanent gluten sensitive enteropathy, has emerged as a widespread health problem. It is considered an immunological disease, possibly of autoimmune type, albeit strictly dependent on the presence in the diet of wheat gluten and similar proteins from rye and barley. There are reasons to believe that the aetiology of coeliac disease is multifactorial, i.e. that other environmental exposures than the mere presence in the diet of gluten affect the disease process. Our studies have shown that prolonged breast-feeding, or perhaps even more important, ongoing breast-feeding during the period when gluten-containing foods are introduced into the diet, reduce the risk for coeliac disease. The amount of gluten consumed is also of importance in as much as larger amounts of gluten-containing foods increase the risk for coeliac disease, while it still is uncertain if the age for introducing gluten into the diet of infants is important. Thus, a challenging possibility, that need to be further explored, is if the coeliac enteropathy can be postponed, or possibly even prevented for the entire life span, by favourable dietary habits early in life.

Lack of cellular and humoral immunological responses to oats in adults with coeliac disease

OBJECTIVE

Recent research suggests that oats do not harm intestinal villi in adults with coeliac disease. As the immunological effects of oats have not been examined in detail, it was decided to compare the immunological responses of a gluten free diet including oats with those of a conventional gluten free diet.

DESIGN

A randomised controlled intervention study over 6-12 months.

SUBJECTS

Forty adults with newly diagnosed coeliac disease and 52 with coeliac disease in remission were examined.

INTERVENTION

The effects of a gluten free diet including oats and a conventional gluten free diet were compared.

MAIN OUTCOME MEASURES

Serum levels of gliadin and reticulin antibodies as well as numbers of intraepithelial lymphocytes (IELs) in intestinal mucosa were examined before and after the intervention.

RESULTS

The rate of disappearance of gliadin and reticulin antibodies did not differ between the diet groups in patients with newly diagnosed coeliac disease. Oats also had no effect on gliadin or reticulin antibody levels in the patients with remission. The number of IELs decreased similarly regardless of the diet of newly diagnosed patients, and no increase in the number of IELs was found in the patients in remission with or without oats.

CONCLUSIONS

These results strengthen the view that adult patients with coeliac disease can consume moderate amounts of oats without adverse immunological effects.

A comparison of diets with and without oats in adults with celiac disease

BACKGROUND

Wheat, rye, and barley damage the small-intestinal mucosa of patients with celiac disease; maize and rice are harmless. The effects of a diet containing oats are uncertain.

METHODS

In a randomized trial, we compared the effects of gluten-free diets without oats and with oats (with a goal of 50 to 70 g per day from three sources: two types of wheat-starch flour mixed with an equal amount of oats, muesli containing 60 percent oats, and rolled-oat breakfast cereal). Fifty-two adults with celiac disease in remission were followed for 6 months and 40 with newly diagnosed disease for 12 months. Endoscopy with duodenal biopsy was performed at the beginning and end of the study.

RESULTS

The mean (+/- SD) oat intake in the oat group was 49.9 +/- 14.7 g per day at 6 months for patients in remission and 46.6 +/- 13.3 g per day at 12 months for patients with newly diagnosed disease. The oat and control groups did not differ significantly in nutritional status, symptoms, or laboratory measures. Patients in remission, regardless of diet, did not have worsening architecture of the duodenal villi or increased mononuclear-cell infiltration. All the patients with new diagnoses were in remission at one year, except for one in the control group. Six patients in the oat groups and five in the control group withdrew from the study.

CONCLUSIONS

Moderate amounts of oats can be included in a gluten-free diet for most adult patients with celiac disease without adverse effects.

Rise and fall of coeliac disease 1960-85

A total of 192 children who presented with coeliac disease to Queen Elizabeth Hospital for Children from 1960-85 were reviewed in order to investigate the frequency and the age of presentation. There was a clear peak in the number of children presenting from 1971-5, and although the numbers declined subsequently they have remained at a level similar to numbers found before 1971. There was no difference in the mode of presentation but there was a definite increase in the age of presentation over the time period reviewed. Breast fed babies presented later than bottle fed babies (14 compared with 9 months) despite a similar age of gluten introduction. Similarly bottle fed babies and breast fed babies presented later after 1975 (10.5 compared with 7 months, and 18 compared with 9.5 months, respectively). Before 1975 the median age of gluten introduction was significantly less than that after 1975 (2 compared with 4 months) and the age of gluten introduction correlated with the age of presentation. It is concluded that breast feeding and the age of gluten introduction may influence the age of presentation of childhood coeliac disease but no clear reasons for the rise in incidence in the 1970s have been determined. It does not appear that the disease is declining, however, in recent years children have tended to present later in life.

Low gluten diet in the treatment of adult coeliac disease: effect on jejunal morphology and serum anti-gluten antibodies

Treatment of patients with coeliac disease with a low gluten containing diet (LGD) remains controversial. We have studied jejunal morphology and antigluten (AG) antibody titres by ELISA in patients on a LGD of 2.5-5 g/day for three to 14 months (median six months) and compared results with patients on a strict gluten free diet (GFD) for six to 27 months (median 13 months). We found no significant difference in villous height or crypt depth (eight LGD v 10 GFD patients) or serum AG-IgA, -IgG, and IgM titres (13 LGD v 12 GFD patients). there was however, a significant increase (p less than 0.05) in intra-epithelial lymphocytes in those patients on a LGD. We conclude that adult coeliac patients can tolerate a LGD without gross morphological change and without initiating significant AG antibody responses.

Coeliac disease among children in Kuwait: difficulties in diagnosis and management

Twenty children with coeliac disease were diagnosed over a five year period in an area with 10,000-12,000 births per year. The average annual incidence was 1:3000 births. All children presented with severe symptoms and rickets was not uncommon (25%). Mean age at onset of symptoms was 38 months (range 6-120) and 72 months at the time of diagnosis (range 13-192), with a mean delay of 34 months. No cases were diagnosed during infancy. The difficulties in the differentiation of coeliac disease from the more common causes of chronic diarrhoea, and problems with diagnosis and management are discussed.

Short stature as the major manifestation of celiac disease in older children

Celiac disease was diagnosed by jejunal biopsy and response to gluten elimination in 11 of 23 children with short stature referred after negative endocrine evaluation. The mean age of the group was 11 years, with a range of 5-16. All had been followed for a mean of 2.5 years at a large pediatric endocrine clinic for the evaluation of growth retardation. Bone age retardation of more than 25 percent of the chronologic age was found in all children. Microcytic anemia and past history of gastrointestinal problems were typical of the celiac group but were not documented in the nonceliac patients. Stool fat excretion was a specific but insensitive test, while the 1-hour blood xylose test was of no value in differentiating between the two groups. Close cooperation between pediatric endocrinology and gastroenterology clinics may be fruitful in the identification of celiac patients, especially in a group of older children with short stature, bone age retardation, and microcytic anemia.

Coeliac disease in identical twins

Coeliac disease occurred at the same age in MZ twins. The diagnosis was confirmed by histology of the small intestine, rapid response to a gluten-free diet, and relapse after reintroduction of gluten.

Gluten challenge in treated coeliac disease

Thirty-two children with a past diagnosis of coeliac disease were reinvestigated by means of gluten challenge. They had received a gluten-free diet for a mean period of 6-5 years (range 0-25-11-0) before gluten challenge, and had a mean age of 9-9 years (range 3-0-15-3) at the onset of challenge. Small intestinal biopsies were performed before and after the gluten challenge (at least 10 g natural gluten per day for 3 months in the majority) and, as judged by light microscopy and morphometric techniques, coeliac disease was confirmed in 25 (78%) of the 32 patients; challenge was continued in the remaining 7 for a total period of 2 years when biopsies were repeated in 6 children and all were normal. Serum and RBC folate, serum iron, Hb level, and clinical symptoms were unpredictable variables in identifying children who developed gluten-induced enteropathies. The social and emotional effects of gluten challenge are discussed. The results highlight the importance of gluten challenge and intestinal biopsy in the diagnosis of coeliac disease and strongly suggest that a normal biopsy after a 3-month gluten challenge (as described above) excludes coeliac disease.

Colonic granulometry in the malabsorption syndromes

After transit through the small intestine barium enters the large intestine and its characteristics in that gut segment can be studied. The pattern of distribution of barium in the colon is always altered in patients with malabsorption syndromes. The physical basis for this alteration is analysed in a manner analagous to that used in soil mechanics. The dispersal of barium granules within the liquid-solid content of the colon is related to certain factors among which is the polarisation and electrical potential of barium particles. A technique using four radiographs which permits evaluation of barium dispersal in the colon - colonic granulometry - is described. Lastly, the authors point out the necessity of classical barium studies in identifying the rare anatomical anomalies that can be the starting point of a typical clinical coeliac syndrome.

Small intestinal biopsy in childhood coeliac disease

Small intestinal biopsies from children with treated and untreated coeliac disease have been analysed morphometrically and compared with controls. Two methods have been used; one, described by Dunnill and Whitehead (1972) provides indices of surface-to-volume ratio and of mucosal volume. The other, described by Meinhard, Wadbrook and Risdon (1965), involves tracing the microscopic image of the biopsy on to computer data cards to produce measured encoded data for direct analysis with a computer.

Biopsies from untreated coeliacs were clearly distinguished from control specimens by both techniques. Comparison of these two groups by computer card morphometry shows the mucosal lesion in coeliac disease to be associated with a spatial redistribution of the tissue components rather than a change in their absolute amounts. No difference in the total mucosal volume was found so that a true mucosal atrophy does not occur in this condition.

Surface-to-volume (c: lh) ratios were measured in twenty-eight children treated empirically with a gluten-free diet for suspected coeliac disease, in biopsies taken before and after a gluten challenge. By this means the diagnosis of coeliac disease was confirmed in eighteen of these patients.

In morphologically normal biopsies correlation of c: lh ratios with age showed significantly smaller values in younger children. Slight changes in biopsies from young children should, therefore, be interpreted cautiously and should not necessarily be regarded as pathological on the evidence of the villous pattern alone.

Failure of laboratory and radiological studies to predict jejunal mucosal atrophy

Of 58 children with suspected malabsorption, 27 were shown to have subtotal or partial atrophy, and 31 had normal mucosal histology. Oral glucose tolerance tests, faecal fat excretion, D-xylose excretion tests, Prosparol absorption studies, haematological investigations, and radiological examination of the small bowel failed to distinguish these two groups and frequently gave misleading results. It is concluded that in suspected coeliac disease small intestinal biopsy should be performed as a primary investigation.

Computer card morphometry of jejunal biopsies in childhood coeliac disease

The histological changes in 95 jejunal biopsy specimens from children have been analyzed by a new mporphometric technique. The microscope image of the specimen is traced directly onto computer data cards. A simple sketch records accurate quantitative data in a matrix of 840 points, retaining the spatial arrangement of the tissue components. The data are fed via an optical mark data card reader, into a mini-computer. FORTRAN IV programs allow calculation of surface area, villous heights, and component volumes in metric units, and of volume proportions, volume-to-volume ratios, and surface-to-volume ratios. Pictorial and numerical printouts are produced, which are suitable for inclusion in the patient's notes. Jejunal biopsies from 37 controls and 26 untreated coeliac patients were clearly distinguished morphometrically. Sixteen pairs of biopsies from coeliac patients on long-term gluten-free diets before, and 12 weeks after, the reintroduction of dietary gluten significantly reflected the effects of gluten challenge. Comparison of control and abnormal biopsies showed a spatial redistribution of the components, more than a change in their absolute amounts. There was no significant differences in the total epithelial volumes in controls, treated or untreated patients, suggesting that the mucosal lesion in coeliac disease is not a true atrophy.

Lack of harmful effect of oats on small-intestinal mucosa in coeliac disease

It is well established that wheat, rye, and barley are harmful to patients with coeliac disease, but the effect of oats remains in doubt. Four patients with coeliac disease, who had shown complete mucosal recovery after prolonged treatment with a strict gluten-free diet, volunteered to consume oats in addition to their gluten-free diet for a period of one month and were studied by jejunal biopsy before and after the experimental period. The patients remained entirely symptom-free and, more important, the jejunal mucosa was undamaged as judged by appearances under dissecting and light microscopes, quantitative histological studies, and disaccharidase content. It is concluded that oats are harmless to coeliac subjects and can be included in a gluten-free diet.

Quantitation of the histological changes found in small intestinal biopsy specimens from children with suspected coeliac disease

The histological appearances in 85 peroral small intestinal biopsies from children have been analysed quantitatively by the method of Dunnill and Whitehead (1972). As applied to such biopsy specimens, this technique provides indices of both the mucosal volume and of the mucosal surface-to-volume ratio. When compared with controls, ;flat' biopsies from children with untreated coeliac disease invariably showed much smaller surface-to-volume (c:lh) ratios. The mucosal volumes (h) of these biopsies were, however, significantly increased. Specimens showing less marked abnormalities (socalled ;partial villous atrophy') had c:lh ratios in an intermediate range, but, like the biopsies from untreated coeliacs, h values were significantly increased. In morphologically normal biopsies correlation of surface-to-volume ratios with age showed that c:lh ratios were significantly smaller in younger children. Some of these lower c:lh ratios overlapped the range observed in abnormal biopsies showing partial villous atrophy. However, in the atrophic biopsies additional histological changes, such as abnormalities of the surface epithelial cells and an increased inflammatory cell infiltration of the lamina propria, were invariably present. Slight changes in biopsies from children under 2 years of age should, therefore, be interpreted cautiously, and should not necessarily be regarded as pathological on the evidence of the villous pattern alone. The quantitative technique employed proved reproducible under normal working conditions, and its greatest practical value would appear to be in following accurately serial changes in biopsies from the same patient.