Coeliac disease-associated risk variants in TNFAIP3 and REL implicate altered NF-kappaB signalling.

OBJECTIVE: Our previous coeliac disease genome-wide association study (GWAS) implicated risk variants in the human leucocyte antigen (HLA) region and eight novel risk regions. To identify more coeliac disease loci, we selected 458 single nucleotide polymorphisms (SNPs) that showed more modest association in the GWAS for genotyping and analysis in four independent cohorts. DESIGN: 458 SNPs were assayed in 1682 cases and 3258 controls from three populations (UK, Irish and Dutch). We combined the results with the original GWAS cohort (767 UK cases and 1422 controls); six SNPs showed association with p<1 x 10(-04) and were then genotyped in an independent Italian coeliac cohort (538 cases and 593 controls). RESULTS: We identified two novel coeliac disease risk regions: 6q23.3 (OLIG3-TNFAIP3) and 2p16.1 (REL), both of which reached genome-wide significance in the combined analysis of all 2987 cases and 5273 controls (rs2327832 p = 1.3 x 10(-08), and rs842647 p = 5.2 x 10(-07)). We investigated the expression of these genes in the RNA isolated from biopsies and from whole blood RNA. We did not observe any changes in gene expression, nor in the correlation of genotype with gene expression. CONCLUSIONS: Both TNFAIP3 (A20, at the protein level) and REL are key mediators in the nuclear factor kappa B (NF-kappaB) inflammatory signalling pathway. For the first time, a role for primary heritable variation in this important biological pathway predisposing to coeliac disease has been identified. Currently, the HLA risk factors and the 10 established non-HLA risk factors explain approximately 40% of the heritability of coeliac disease.

Review article: coeliac disease in later life must not be missed.

BACKGROUND: The presenting symptoms of coeliac disease are often subtle and the diagnosis is frequently delayed or overlooked. Therefore, especially elderly patients may be denied the benefits conferred by gluten free diet which can be dramatically life-changing. AIM: To review the occurrence, clinical features, diagnosis and management in coeliac patients detected later in life. METHODS: To review manuscripts concerned with coeliac disease in the elderly and to derive subgroups of elderly people from publications on the disorder. RESULTS: Approximately a quarter of all diagnoses are now made at the age of 60 years or more and a fifth at 65 years or over. About 4% are diagnosed at 80 years or above. Around 60% remain undetected, since their symptoms are often subtle: tiredness, indigestion, reduced appetite. Good compliance with gluten free diet, resolution of symptoms and improvement in laboratory indices can be achieved in over 90% of patients. CONCLUSIONS: Coeliac disease not uncommonly presents for the first time in older patients and is an important diagnosis to make.

Risk of malignancy in diagnosed coeliac disease: a 24-year prospective, population-based, cohort study.

BACKGROUND: There is recent evidence from studies of hospitalized and of undiagnosed patients that the risk of lymphoma for people with coeliac disease may be lower than previously thought. In addition, there have been no precise estimates of small bowel lymphoma risk due to a lack of population data. AIM: To examine these and other malignant risks in a cohort of patients more typical of those seen in routine clinical practice. METHODS: A prospective cohort study of incident malignancy rates in patients with coeliac disease in southern Derbyshire compared with general population figures. RESULTS: During 5684 person years of follow-up 31 malignancies (excluding non-melanoma skin cancer) occurred in comparison with 30.30 expected [standardized incidence ratio (SIR) 1.02 (0.69-1.45)]. There were four non-Hodgkin's lymphomas (0.69 expected) SIR 5.81 (1.58-14.86), of which one originated in small bowel (0.02 expected) SIR 40.51 (1.03-225.68). GI malignancy occurred in nine (5.71 expected) SIR 1.58 (0.72-2.99), and breast cancer in three (5.08 expected) SIR 0.59 (0.12-1.73). CONCLUSIONS: There is no increase in the risk of incident malignancy in this population and the risk of non-Hodgkin's lymphoma in general or of the small bowel is lower than previously found from UK coeliac cohorts.

Primary small-bowel malignancy in the UK and its association with coeliac disease.

BACKGROUND: Malignancies of the small intestine are rare, accounting for <2% of all cancers of the gastrointestinal tract. There is little information about the presentation and prognosis of these tumours, and the frequency of established risk factors. AIM: To estimate the frequency of small-bowel malignancy in the UK, and its relationship to the presence of coeliac disease. DESIGN: Survey of clinicians registered with the British Society of Gastroenterology. METHODS: Data were collected monthly from June 1998 to May 2000. Clinicians (n=1327) were asked by post to report newly diagnosed cases of primary small-bowel malignancy. A form was sent to reporting clinicians, requesting an anonymous identifier, type of malignancy, and whether coeliac disease was present. A detailed questionnaire followed, requesting further clinical and pathological details. RESULTS: Clinico-pathological data were ascertained for 395 cases, including 175 adenocarcinomas, 107 lymphomas and 79 carcinoid tumours. In 13% of adenocarcinoma cases and in 39% of lymphomas, there was a diagnosis of coeliac disease. Survival rates at 30 months for adenocarcinomas, lymphomas and carcinoid tumours were 58%, 45% and 78%, respectively. Prognosis of all tumours was inversely related to stage at presentation, and lymphomas associated with coeliac disease were associated with a poorer prognosis. DISCUSSION: This study provides additional evidence that coeliac disease confers susceptibility to adenocarcinoma of the small bowel, as well as lymphoma. The long time from the onset of symptoms to diagnosis of small bowel tumours is of concern, as this delay is reflected in the high proportion that presented with metastatic disease. Although the absolute risk of malignancy is small, coeliac disease complicated by malignancy appears to be poorly controlled.

Coeliac disease and malignancy.

The development of malignancy, particularly lymphoma, is the most serious complication to affect patients with coeliac disease. Although the association has been known for about 40 years, there are still gaps in our understanding. The prevalence of lymphoma and why only some coeliac patients develop this are not clear but environmental and genetic factors must be at work. Based on data from a large coeliac clinic in Derby, about 55 lymphomas per year would arise in the coeliac population of the United Kingdom, of which half would affect the small bowel. Whether patients with coeliac disease who have atypical or no symptoms at diagnosis, are at the same risk as those who are diagnosed as a result of classical symptoms as was more the case in the past, is not known. Some patients, however do have coeliac disease and lymphoma diagnosed at the same presentation. This consideration has implications for initiating screening programmes to detect coeliac disease and thus offer patients a gluten-free diet early that would help to reduce the risk of lymphoma from developing. In this context, case-finding rather than blanket population screening is to be recommended on present evidence. Research into the role of intraepithelial lymphocytes in the genesis of lymphoma has indicated that non-responsive coeliac disease (refractory sprue) and ulcerative jejunoileitis (ulcerative jejunitis) are part of the lymphoma spectrum. The diagnosis of lymphoma can be difficult and the prognosis, in general, is poor, although with modern chemotherapeutic regimes and surgery in selected cases, long-term survival is possible. The best option is to try and prevent lymphoma from arising by advising all patients to adhere to a strict gluten-free diet. Malignant complications of coeliac disease are uncommon but will continue to challenge clinicians and clinical scientists. Unravelling the mechanisms that contribute to the development of lymphoma and other tumours in coeliac disease may well contribute to a wider understanding of oncogenesis.

IgA-antitissue transglutaminase: validation of a commercial assay for diagnosing coeliac disease.

We have evaluated a commercial assay for serum IgA class antibodies to tissue transglutaminase, the enzyme identified as the major endomysial autoantigen in coeliac disease (CD). Sera were available from 130 adults diagnosed with CD in Southern Derbyshire between 01 01 97 and 31 12 99. Sera from 100 patients without villous atrophy on small intestinal biopsy were controls. The ability of the assay to detect abnormally low total IgA levels was assessed using sera from 18 subjects with IgA deficiency. Sensitivity and specificity of this IgA-anti tissue transglutaminase (tTGA) assay (86.2%, 91.0%) were inferior to endomysial antibody (EMA; 93.8%, 100%). tTGA has significantly higher sensitivity than IgA-antigliadin (76.2%). tTGA was appropriately undetectable (<0.03 U/mL) in 17 of 18 subjects with selective IgA deficiency. The high likelihood ratio (35) for tTGA at levels >9.0 U/mL and methodological advantages over EMA suggest that tTGA could be used as a first line diagnostic test for CD. At tTGA levels of 4-9 U/mL, use of EMA as a second line test would improve specificity.

Patient perceptions of the burden of coeliac disease and its treatment in the UK.

BACKGROUND: Coeliac disease affects about 1% of the population, with the majority being undetected. As a consequence, there have been calls for the introduction of screening. Before screening is given serious consideration, it is important to assess how acceptable early diagnoses and treatment would be. AIM: To assess patients' views as to the diagnosis and treatment of disease. METHODS: Coeliac disease patients who had taken a gluten-free diet for at least 12 months (mean 60 months) were mailed a questionnaire. Coeliac patients presenting with typical classical symptoms were compared with those diagnosed without such symptoms. RESULTS: Overall, 83% (147/177) of coeliac patients returned the questionnaires. Two-thirds (68%, 101/147) reported that their dietary restrictions reduced their enjoyment of food; 46% (68/147) believed their food cost them more and estimated this to be an extra 10 pounds sterling (16 euros) per week. Of those reporting greater cost, 31 (21%) said this was a problem for them. Half (54%, 80/147) reported doing things they enjoyed less often because of their diet, with the most common activity sacrificed being dining out (n = 65). In spite of these findings, 81% (119/147) reported being pleased that they were diagnosed, with 66% (59/89) of cases with classical symptoms wishing they had been diagnosed earlier compared with 45% (23/51) of those without such symptoms (chi(2) = 6.0, P < .05). In contrast, 27% (14/51) of coeliacs diagnosed without classical symptoms regretted being diagnosed with their condition compared with 10% (9/89) of those with classical symptoms (chi(2) = 7.1, P < .01). CONCLUSIONS: Even after several years of a gluten-free diet, many patients with coeliac disease regard it as a substantial burden, with a quarter of screen detected patients reporting regret at being diagnosed. Our findings question how acceptable screening for coeliac disease would be in people with minimal or no symptoms.

Coeliac disease: a biopsy is not always necessary for diagnosis.

BACKGROUND: In view of the high diagnostic accuracy of immunoglobulin-A-tissue transglutaminase antibodies for detecting coeliac disease, we have explored whether a small bowel biopsy is always required to establish the diagnosis. AIM: To define the transglutaminase antibody level giving a positive predictive value for coeliac disease of 100% and to subsequently assess the proportion of new diagnoses of coeliac disease having such a result. METHODS: The Celikey kit (Phadia GmbH, Frieburg, Germany) was used to measure transglutaminase antibody levels. RESULTS: All patients with transglutaminase antibody levels >30 U/mL, i.e. 10 x upper limit of normal in 2002/2003 had characteristic small bowel mucosal lesions. In a subsequent audit, 58% of 112 new diagnoses of coeliac disease in 2004/2005 had levels above this cut-off value. CONCLUSIONS: We have shown that a transglutaminase antibody level can be defined which gives a positive predictive value of 100% for coeliac disease. From published data, these observations can be extended to most second-generation transglutaminase antibody kits. Our data provide further evidence that diagnostic guidelines could be modified so that small bowel biopsy is no longer regarded as mandatory in patients with such high transglutaminase antibody levels. This will avoid an invasive procedure and lead to a more rapid diagnosis and earlier treatment for over half of the new patients with coeliac disease.

Screening for coeliac disease in type 1 diabetes.

The average prevalence of coeliac disease among children with diabetes mellitus in 26 reports was 4.5% (0.97-16.4%). Malabsorption, unstable diabetes, and growth failure, indicate that coeliac disease may be present. Even those who are apparently asymptomatic may have subtle complaints indicative of coeliac disease if a careful history is taken. Ill health may only be recognised in retrospect following the benefits conferred by a gluten free diet. For these reasons it is recommended that a screening programme should be instituted to detect coeliac disease in these children. Parents and where possible children themselves, should be fully involved at all stages of the screening, diagnostic, and treatment process.

IgA antibodies to human tissue transglutaminase: audit of routine practice confirms high diagnostic accuracy.

BACKGROUND: The diagnostic accuracy of IgA tissue transglutaminase antibodies (TGA) for coeliac disease (CD) has been assessed following the introduction of the test into routine practice in 2002. METHODS: Specificity was assessed in serum samples received from 1554 adults for routine coeliac serology. The population for assessing sensitivity was 75 consecutive new adult diagnoses of CD. TGA was measured by enzyme-linked immunoassay using human tissue transglutaminase as antigen. Concordance between TGA and endomysial antibody (EMA) was also assessed. RESULTS: The prevalence of new diagnoses of CD in the population tested was 2.8% with similar proportions of new diagnoses in males and females. The positive predictive values at a cut-off of 3 units/mL were 0.77 for samples from Primary Care and 0.92 for samples from Hospital sources, with a sensitivity of 92%. At TGA <3 units/mL, EMA was usually negative; when TGA was >4.9 units/mL, EMA was rarely negative. CONCLUSIONS: We have assessed the role of TGA in routine clinical practice and confirmed high diagnostic accuracy. Sensitivity (92%) is identical to the sensitivity for EMA. IgA deficiency should be excluded in samples showing low absorbance readings in the TGA assay and interference from monoclonal and polyclonal IgA should be excluded in samples with slightly raised TGA levels and negative EMA. TGA is recommended as the first-line serological test for coeliac disease.

Cigarette smoking and adult coeliac disease.

BACKGROUND: While coeliac disease is clearly induced by dietary gluten ingestion in genetically susceptible individuals, other environmental factors may influence the onset of disease. Two studies have suggested that cigarette smoking has a protective role, but a third has not. METHODS: We examined the relationship between cigarette smoking and coeliac disease in individuals with coeliac disease diagnosed in adulthood from two large population-based disease registers and age and sex-matched controls from local general practitioner lists. Participants were mailed a three-page lifestyle and general health questionnaire. Smoking habits of coeliacs were compared with controls and with habits reported in the Health Survey for England 1995. RESULTS: An inverse association between current smoking and adult coeliac disease was identified (odds ratio: 0.77 (95% CI 0.56-1.06)) and remained when comparing ever smoked versus never smoked (odds ratio: 0.83 (0.68-1.00)). When the smoking habits of the coeliacs were compared with the national figures, the number of coeliacs who currently smoked was 40% lower than expected (smoking ratio 0.60, 0.46-0.78). This inverse association was accounted for by the behaviour of the 35-54-year age group (odds ratio for ever smoked 0.67 (0.51-0.89)). There was no association with having ever smoked in the younger age group (odds ratio: 1.44 (0.75-2.78)) or the older group (odds ratio: 0.92 (0.67-1.26)). CONCLUSIONS: There was an inverse association between adult coeliac disease and cigarette smoking which was accounted for by middle-aged coeliacs having never smoked. These results are consistent with an age-dependent interaction between cigarette smoking and the other environmental factors implicated in coeliac disease, including gluten.

Fracture experience of patients with coeliac disease: a population based survey.

BACKGROUND: While coeliac disease is now recognised as being associated with both osteoporosis and osteomalacia, the size of any increase in the risk of fracture in patients with coeliac disease compared with the general population has not been quantified. AIM: To examine the fracture experience of adults with coeliac disease compared with the general population. SUBJECTS: Patients with coeliac disease diagnosed in adulthood and born before 1950, selected from two large population based disease registers, and age and sex frequency matched controls identified from local general practitioner lists. METHODS: A four page lifestyle and general health questionnaire which included specific questions about fracture experience. RESULTS: Analysis was performed on 244 patients with coeliac disease and 161 controls, giving response rates of 89% and 72%, respectively. Eighty two (35%) coeliac patients and 53 (33%) controls reported ever having sustained one or more fractures, giving an age and sex adjusted odds ratio of 1.05 (95% confidence interval (CI) 0.68-1.62). The most common fracture site reported was the forearm or wrist, with an adjusted odds ratio of 1.21 (95% CI 0.66-2.25) for patients with coeliac disease having had a forearm or wrist fracture. Low trauma fractures were reported by 37 patients with coeliac disease (15.7%) and by 21 controls (13.8%), with an adjusted odds ratio of 1.16 (95% CI 0.65-2.10). The risk of low trauma fracture was slightly higher in coeliac men than women (odds ratio 1.28 compared with 1.12), but this difference was not statistically significant (p=0.84). After adjustment for age, sex, body mass index, and smoking status, patients with coeliac disease reported 13% more low trauma fractures than controls (odds ratio 1.13, 95% CI 0.60-2.12). There was no difference in low trauma fracture risk before and after diagnosis of coeliac disease. CONCLUSION: No overall increased fracture risk in patients with coeliac disease was observed. Although severe osteoporosis may develop in a subset of patients, as a whole patients with coeliac disease do not represent a population at particularly high risk of osteoporotic fracture and thus targeting them for osteoporosis screening and treatment is not justified.

Neurological complications of coeliac disease.

A variety of neurological disorders have been reported in association with coeliac disease including epilepsy, ataxia, neuropathy, and myelopathy. The nature of this association is unclear and whether a specific neurological complication occurs in coeliac disease remains unproved. Malabsorption may lead to vitamin and trace element deficiencies. Therefore, patients who develop neurological dysfunction should be carefully screened for these. However, malabsorption does not satisfactorily explain the pathophysiology and clinical course of many of the associated neurological disorders. Other mechanisms proposed include altered autoimmunity, heredity, and gluten toxicity. This review attempts to summarise the literature and suggests directions for future research.

Autoantibodies to human tissue transglutaminase: superior predictors of coeliac disease.

BACKGROUND: Using selected sample populations, we compared sensitivity and specificity of autoantibodies to guinea pig and human tissue transglutaminase to assess if the human antigen is superior for predicting coeliac disease. METHODS: Four commercial enzyme-linked immunoassay kits using human tissue transglutaminase as antigen were used to measure autoantibody levels in serum samples from untreated adult coeliacs (n = 32). They were from a series of 130 cases diagnosed between 1997 and 1999 and chosen to bias the group towards subjects with negative autoantibodies when measured with guinea pig tissue transglutaminase as antigen. Samples from 38 control subjects (biased towards false-positive levels with guinea pig antigen) were used to compare specificity. We also assessed if human antigen kits could differentiate between levels in normal subjects and in selective IgA deficiency. RESULTS: Sensitivity for coeliac disease in this selected group using the human antigen kits ranged from 88% to 100%. Three kits showed significantly higher specificity (82%-97%, P < 0.05) than the guinea pig antigen kit (71%) for the samples studied. No kit achieved complete separation between normal autoantibody levels and lower levels in selective IgA deficiency. CONCLUSIONS: All human antigen kits showed significantly higher sensitivity for coeliac disease compared to guinea pig antigen (P < 0.001). Receiver operating characteristic curves confirmed the superior diagnostic accuracy of the human antigen kits.

Seroprevalence, correlates, and characteristics of undetected coeliac disease in England.

OBJECTIVE: To examine the seroprevalence, correlates, and characteristics of undetected coeliac disease in a large adult population sample in Cambridge, UK. METHODS: The Cambridge General Practice Health Study invited individuals from 12 general practices, aged 45-76 years, to attend for a health survey that included a bone density measurement, between 1990 and 1995. A total of 7550 participants' serum samples were tested for antiendomysial antibody (EMA). Seroprevalence of undetected coeliac disease was based on EMA positivity. Differences between EMA positive and negative participants of various physiological correlates and reported characteristics were estimated by multivariate logistic and linear regression and adjusted for age, sex, social class, and smoking behaviour. RESULTS: The seroprevalence of undetected coeliac disease in this general population sample aged 45-76 was 1.2% (95% confidence interval (CI) 0.9-1.4). EMA positive participants (n=87) were on average slightly lighter by 2.2 kg (p=0.08), were more likely to have reported their general health as being "good or excellent" (odds ratio (OR) 1.76 (95% CI 0.90-3.46)), and were less likely to report being a current smoker (OR for current versus never 0.36 (95% CI 0.14-0.90)) than EMA negative participants. EMA positivity was associated with an 8% reduction in mean serum cholesterol (0.5 mmol/l; p<0.01) and reductions in mean haemoglobin (0.3 g/dl; p<0.01), total protein (1.0 g/l; p<0.05), and corrected serum calcium (0.02 mmol/l; p<0.05). There was an increased risk of osteoporosis in EMA positive participants (OR 3.1 (95% CI 1.3-7.2)) and of mild anaemia (OR 4.6 (95% CI 2.5-8.2)) compared with EMA negative participants. CONCLUSIONS: Undetected coeliac disease is likely to affect approximately 1% of the population of England aged 45-76 years, a value similar to several other countries. Those affected report "better health" but they do have an increased risk of osteoporosis and mild anaemia. In contrast, they have a favourable cardiovascular risk profile that may afford protection from ischaemic heart disease and stroke.

Variation in the CTLA4/CD28 gene region confers an increased risk of coeliac disease.

Susceptibility to coeliac disease involves HLA and non-HLA-linked genes. The CTLA4/CD28 gene region encodes immune regulatory T-cell surface molecules and is a strong candidate as a susceptibility locus. We evaluated CTLA4/CD28 in coeliac disease by genetic linkage and association and combined our findings with published studies through a meta-analysis. 116 multiplex families were genotyped across CTLA4/CD28 using eight markers. The contribution of CTLA4/CD28 to coeliac disease was assessed by non-parametric linkage and association analyses. Seven studies were identified that had evaluated the relationship between CTLA4/CD28 and coeliac disease and a pooled analysis of data undertaken. In our study there was evidence for a relationship between variation in the CTLA4/CD28 region and coeliac disease by linkage and association analyses. However, the findings did not attain formal statistical significance (p = 0.004 and 0.039, respectively). Pooling findings with published results showed significant evidence for linkage (504 families) and association (940 families): p values, 0.0001 and 0.0014 at D2S2214, respectively, and 0.0008 and 0.0006 at D2S116, respectively. These findings suggest that variation in the CD28/CTLA4 gene region is a determinant of coeliac disease susceptibility. Dissecting the sequence variation underlying this relationship will depend on further analyses utilising denser sets of markers.

Crohn's disease in West Indians

An epidemiological survey in the city of Derby from 1976 to 1985 indicated that there was no significant difference in the incidence of Crohn's disease in West Indians (4.5-5.6/10x10x10x10x10x10/yr) and the caucasian population (7.0/10x10x10x10x10/yr). These results indicate that West Indians are not genetically protected against the development of Crohn's disease. (AU)