An autosomal screen for genes that predispose to celiac disease in the western counties of Ireland.

Celiac disease is a strongly heritable gastrointestinal illness that is an especially important model of the genetically complex multifactorial immune mediated diseases. The HLA component of celiac disease (a specific HLA-DQ heterodimer)is largely established and is relatively uncomplicated, and the environmental component (gluten and related grain storage proteins in the diet) is remarkably well understood. Previous family studies of celiac disease suggested that there is at least one important non-HLA locus. This locus may be a stronger genetic factor than HLA, and it apparently has a recessive mode of inheritance. We used a three step genome screening protocol to identify loci that contribute to celiac disease in the western counties of ireland, a region with the highest prevalence of celiac disease in the world. The most significant of several possible non-HLA loci that we found was on chromosome 6p about 30 cM telomeric from HLA. It has a multipoint maximum lod score of 4.66 (compared with 4.44 for HLA-DQ) and appears to have a recessive mode of inheritance. Our study localizes and provides strong evidence for linkage of at least one non-HLA locus to celiac disease and may serve as a prototype for an efficient approach to screening the human genome for loci that contribute to complex diseases.

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.

Structure-activity relationships for the inhibition of acrosin by benzamidine derivatives.

A series, consisting of 52 benzamidine derivatives, was evaluated for inhibitory activity against homogeneous boar sperm acrosin. All of the compounds in the series proved to be more potent than benzamidine (Ki = 4.0 x 10(-6) M), with one of the derivatives, alpha-(4-amidino-2,6-diiodophenoxy)-3-nitrotoluene (compound 16), showing outstanding potency with a Ki value of 4.5 X 10(-8) M. Although all of the derivatives were effective acrosin inhibitors, structural specificity was observed within homologous groups of compounds. The information gained from this preliminary study should prove extremely beneficial in the design and synthesis of future acrosin inhibitors.

HLA class II frequencies in celiac disease patients in the west of Ireland.

Restriction fragment length polymorphism analysis, using a single restriction enzyme TaqI-multiple-probe system for HLA-DRB1-DQB1 and -DQA1, was used to determine HLA-DR and -DQ frequencies in 56 unrelated celiac patients and 47 unrelated controls from the west of Ireland. In addition, HLA-DPB1 allelic frequencies were determined in the same group of patients and controls by using the technique of enzymatic DNA amplification of the polymorphic second exon of HLA-DPB1 genes in conjunction with sequence-specific oligonucleotide probing. The results suggest that HLA-DQ rather than HLA-DR is more important in conferring susceptibility to celiac disease. Furthermore, no association between HLA-DP and celiac disease was found in this study.

Extended major histocompatibility complex haplotypes in celiac patients in the west of Ireland.

The highest reported prevalence of celiac disease (gluten-sensitive enteropathy) is found in the West of Ireland. Recent genetic data have suggested that major histocompatibility complex-linked loci may have a dominant genetic effect for disease susceptibility in this population compared with a recessive effect in other groups. To further understand the role of the MHC in celiac disease in the West of Ireland, we analyzed markers for 22 MHC haplotypes from celiac patients and compared them with 18 nontransmitted haplotypes found in the parents of celiac children, and with reported haplotypes from other populations. An extended MHC haplotype including [HLA-B8, DR3, DQw2, Bf*S, C4A*Q0, and C4B*1] accounted for 50% of celiac haplotypes but only 27% of nontransmitted parental haplotypes. Compared with other reported haplotypes in celiacs, patients from the West of Ireland show a higher prevalence of HLA-A1 as a component of this extended haplotype, suggesting that although the core haplotype is similar between Irish patients and others, the celiac population in the West of Ireland differs at other HLA loci. We did not observe any other common haplotypes among our patients unlike the situation in other populations. These differences may underlie the possible dominant effect of HLA-linked loci and the unusually high prevalence of celiac disease in the Irish population. We also found that the serum levels of complement components C3c, C4, and factor B were significantly lower among celiac patients than nonceliacs. The lower serum level of C4 appears to be related to the presence of deletions and null alleles at the C4A and C4B loci in celiacs.

Abnormal pancreolauryl tests in coeliac disease: lack of correlation with the degree of intestinal mucosal damage.

AIMS: To determine the frequency of abnormal pancreolauryl tests in untreated and treated adults with coeliac disease and to see whether abnormalities in treated coeliac patients correlate with the degree of recovery of intestinal morphology or brush border enzyme activity. METHODS: Pancreolauryl tests were performed in a study population of 57 adult coeliac patients (25 on gluten containing diets and 32 on gluten free diets), 59 symptomatic controls, and eight patients with pancreatic disease. Brush border enzyme activity and morphological assessment were performed on small intestinal biopsies in 27 of the treated coeliac patients. RESULTS: Forty per cent of untreated coeliac patients and 18% of treated coeliac patients had abnormal tests. In treated coeliac patients, no significant correlation was detected between the pancreolauryl test result and either brush border enzyme activity or morphological parameters. CONCLUSION: Abnormal pancreolauryl test results are common in untreated and treated adult coeliac disease patients. Abnormalities in treated coeliac patients do not correlate with the degree of recovery of small intestinal morphology or brush border enzymes.

Lymphocytic gastritis and coeliac disease: evidence of a positive association.

AIMS: To investigate the prevalence of lymphocytic gastritis in patients with coeliac disease. METHODS: Gastric biopsies from 70 patients with coeliac disease were examined by light microscopy for the presence of lymphocytic gastritis, defined as 25 or more intraepithelial lymphocytes/100 gastric columnar epithelial cells. RESULTS: Lymphocytic gastritis was found in seven cases. Positive cases had a mean of 32.1 intraepithelial lymphocytes/100 columnar cells, compared with a mean of 13.9 in negative cases, and 5.15 in noncoeliac controls. No differences were found for age, sex, gastric corpus or antrum, or degree of inflammation in the gastric lamina propria. All intraepithelial lymphocytes were of T cell lineage. Cases not showing lymphocytic gastritis did however show significantly increased gastric intraepithelial lymphocytes compared with non-coeliac controls. Eighteen of 70 cases were positive for Helicobacter pylori, and four of seven cases of lymphocytic gastritis were H pylori positive; no significant difference was observed between H pylori positive and negative patients. Three cases had concomitant ulcerative enteritis, of which none showed lymphocytic gastritis, while five cases had concomitant enteropathy associated T cell lymphoma, of which one showed lymphocytic gastritis. CONCLUSIONS: Lymphocytic gastritis occurred in 10% of patients with coeliac disease. Cases without lymphocytic gastritis nevertheless showed increased gastric intraepithelial lymphocytes. Coeliac disease may on occasion be a diffuse lymphocytic enteropathy occurring in response to gluten. Lymphocytic gastritis outside coeliac disease may involve an immune response to luminal antigens, such as H pylori, not unlike the response to gluten in patients with coeliac disease.

Intestinal lactase, sucrase and alkaline phosphatase in relation to age, sex and site of intestinal biopsy in 477 Irish subjects.

Small intestinal lactase, sucrase and alkaline phosphatase activities were measured in histologically normal peroral intestinal biopsies from 477 individuals. Enzyme activities varied with age, sex, site of biopsy, and were lowest in post-weaning children and highest in young adults. Lactase activity does not decrease with advancing age.

Intestinal lactase, sucrase, and alkaline phosphatase in 373 patients with coeliac disease.

Lactase, sucrase, and alkaline phosphatase activities were measured in 833 peroral small intestinal biopsies from 373 patients with coeliac disease. Enzyme activities decreased with increasing degrees of mucosal damage. Enzyme activities in mucosae of patients with coeliac disease in remission were lower than in control groups matched for age, sex, and site of biopsy. Enzyme activities were measured in 81 patients when the mucosa was severely damaged and later when considerable improvement had occurred. Lactase activity remained low in 13% of patients under the age of 18 and in 33% of those over 18 years. Sucrase activity usually improved with histological recovery, but alkaline phosphatase activity tended to remain depressed in patients in whom lactase activity failed to improve.

The 15 g D-xylose absorption test: its application to the study of coeliac disease.

The absorption of xylose following an oral load of 15 g D-xylose has been studied by serial blood levels in 17 untreated adult coeliac patients, 21 treated coeliac patients, and 30 non-coeliac patients. A statistically significant difference in xylose blood levels was found between untreated coeliac and non-coeliac patients at all the times studied, but a complete separation between these two groups occurred only at the 75 minute stage. The reproducibility of absorption was assessed by repeating the test in 16 subjects. The 95% confidence limits of the standard error of estimate are narrowest at 75 and 90 minutes.

Non-attendance at outpatient clinics at the Regional Hospital, Galway, Ireland.

This paper examines the issue of non-attendance at outpatient clinics at the Regional Hospital, Galway, from the viewpoint of the patients who include both urban and rural residents. The results of a questionnaire survey of outpatients attending general and specialist medical and surgical clinics illustrate that very substantial costs are incurred and long periods of time are spent travelling by many patients. Females, and married females in particular, experience special difficulty in keeping appointments. Non-attendance increases as the cost of transport increases but many patients seriously underestimate the real cost of travel. Patients who have been attending over long periods of time have the worst record of non-attendance. It is recommended that any reorganisation of hospital outpatient systems in rural areas such as Western Ireland should take account of the particular needs of widely dispersed populations.

T cell receptor gamma gene polymorphisms and class II human lymphocyte antigen genotypes in patients with celiac disease from the west of Ireland.

Although celiac disease has one of the strongest human lymphocyte antigen (HLA) class II associations of any human illness, it is clear that at least one gene that is not linked to the HLA region also is required for its pathogenesis. The occurrence of large numbers of gamma delta T cells in the bowel mucosa of patients and the recent description of T cell receptor (TCR) gamma chain polymorphic variants identified by restriction fragment length polymorphism analysis led the authors to examine TCR gamma genotypes in relation to HLA-DR, DQ genotypes in 89 patients with celiac disease and 55 control subjects from the West of Ireland. The overall frequency of TCR gamma genotypes in patients and control subjects was comparable. However, most of the patients had 1 of 3 HLA-DR3 genotypes (DR3/15, 3/7, or 3/3), and there was a significant alteration of the expected frequency of TCR gamma genotypes among patients with these three genotypes. The major differences were an increased association of HLA-DR3 homozygosity, with TCR gamma genotypes having a 16.0 kb fragment and an increased frequency of DR3/7 heterozygosity and decreased frequency of DR3/15 heterozygosity, respectively, in association with the TCR gamma 13.0/11.3 kb genotype. Based on their results, there is the possibility that an interaction between the products of two polymorphic and unlinked gene regions contributes to the pathogenesis of celiac disease.

Gm typing of Irish coeliac patients and controls does not help locate the "second" coeliac gene.

A two gene model has been proposed to explain the inheritance of coeliac disease (CD). One gene is on chromosome 6 in the MHC complex (HLA associated). It has been suggested the second gene is located on chromosome 14, in or near the region encoding for immunoglobulin heavy chain allotypes (Gm types). In a study of 102 unrelated Irish coeliacs and a group of ethnic controls, we have failed to show an association of CD with any particular Gm type or types. There is no evidence to confirm that a gene on chromosome 14 is implicated in the inheritance of CD.

Alpha 1-antitrypsin phenotypes in coeliac patients and a control population in the west of Ireland.

alpha 1 antitrypsin or protease inhibitor (Pi) phenotyping was carried out on 111 coeliac disease patients (CD) and 250 controls. The Pi MM phenotype was present in 95 (85.6%) of the coeliacs and 225 (90%) of the controls. The groups did not differ significantly with regard to Pi phenotypes. In the CD group the Pi Phenotype did not relate to HLA B8 or DR3 status. Associated diseases in the CD patients did not correlate with Pi phenotype.

Salivary SIgA and SIgA 1 in coeliac disease, inflammatory bowel disease and controls.

Levels of secretory IgA1 (SIgA1) in the saliva have not been measured previously in either coeliac disease (CD) or inflammatory bowel disease (IBD). Saliva was collected from coeliacs, IBD patients and controls. The concentration of total SIgA in saliva was measured by enzyme linked immunosorbent assay (ELISA) with an anti-human SIgA antibody as the bound phase and human SIgA isolated from colostrum as the standard. The concentration of SIgA1 was determined using an ELISA with a lectin with a high affinity for human SIgA1. The IBD patients have a significantly higher concentration of SIgA1 than the controls. The rate of secretion of saliva and %SIgA1 was significantly lower in coeliacs than in the control and IBD groups. The rate of secretion of SIgA1 was significantly higher in the IBD than in the coeliacs. We describe hitherto unreported levels of SIgA1 in CD and IBD.

Ulcerative enteritis--atypical features.

A 40 year old man with two month history of vomiting and weight loss, was found to have multiple strictures in his small bowel. Investigations outruled known causes of small bowel ulceration, and the flat bowel mucosa did not respond to a gluten free diet. Treatment with steroids conferred a temporary benefit, however, small bowel ulceration persisted.

Histocompatibility antigens and haemochromatosis in Ireland.

Twenty patients with primary idiopathic haemochromatosis were tissue typed. HLA-A3 and B7 were increased in frequency. The significance of these findings in relation to other studies is assessed.