Deliverables Dissection of the complex molecular and cellular events occurring in the biopsies of small intestine isolated from celiac patients Dissection of the complex molecular and cellular events occurring in the biopsies of small intestine isolated from celiac patients as a response to gliadin challenge yielded several new findings. Data obtained through collaborative effort demonstrated that the gliadin molecule induces several immunological type responses. The complex signalling mechanism is now better understood. The data we have obtained show that the DQ8-restricted gliadin epitope, identified for its activity on T cell clones is also active in the organ culture system of the treated coeliac mucosa. In fact, for the first time gliadin peptides have been shown to display different biological activity in different subsets of coeliac patients. It is still unclear if the response of coeliac patients is directed against a few or multiple peptides, but our observations raise the issue of their immunogenicity depending on the genetic make up of the patient. No differences were noted between the native or the deamidated form of the peptides, when all the in vitro responses were analysed. Though recent studies provided the molecular basis controlling the recognition and generation of immunodominant gliadin cell epitopes by mucosal CD4+ T cells there is evidence, supported by studies of several groups, that an other region of alpha gliadin has the ability to induce disease specific modifications. This region of gliadin is not a T cell epitope. There is also evidence suggesting that an early induction of an inflammatory response precedes the antigen specific T celI response and the definition of this early response represents an important quest to define the full picture of the pathogenesis of coeliac disease. Our data provide a new angle to interpret the pathogenic cascade of CD. Gliadin specific T cell activation is the fundamental step in CD, but it remains to be explained why only a small proportion of HLA DQ2 individuals produce a pathogenic and disease specific T cell activation. The biochemical rules controlling HLA binding of gliadin peptides are obviously identical in all HLA DQ2, coeliac and non coeliac, individuals but a series of other genetic loci have been implicated. It has been reported that IFN-B therapy might be a factor in the initiation of CD and potentially concomitant viral infections, by inducing IFN- release, might contribute to disease initiation and evolution. These studies further indicate the essential involvement of innate response, as the type II interferon are mainly produced by cells of the innate immune system. However, a recent study on identical twins has demonstrated a very high, compared to other autoimmune diseases, concordance rate. These data argue against the idea that danger signal is always provided by a second environmental factor, besides gliadin. It follows that gliadin should have the ability to induce a complete activation of the immune system (adaptive and innate). The induction of IL-15 release by gliadin supports this notion as IL-15 is a typical cytokine of the innate immune system. In CD IL-15 could represent an ideal therapeutic target as it directly induces some epithelial disease specific changes and sustaining a persistent activation of the adaptive immune system. In this context it is very well known that IL-15 provides powerful anti-apoptotic signal for recently activated T cells, allows their migration and set a Thl like response as observed in CD. The inhibition of activation of the innate immune system in CD may therefore represent a useful therapeutic strategy to control disease evolution. Three new chromosomal regions were identified, in addition to the already established HLA-B region by using DNA genotyping and sequencing of the largest ever Celiac disease patients DNA bank The work carried out during this 3 year project has brought significant advances in our knowledge of the Coeliac genetic make-up associated with the disease. Building on smaller studies where the size of the samples was the limiting factor for the accuracy of the analysis, we were able to build a pan-European data bank of unprecedented size that allowed for the required samples content. The building of this data bank and the good spirit inside the Consortium made also this effort very enjoyable. Several key results have been obtained: - 88% of celiac patients are DQ2 positive; 6% are DQ8 positive and 5,6% have only half of the DQ2 heterodimer. Only 3 out of 1008 patients were to be classified in other HLA categories. However the relative risk associated to DQ genotypes are clearly dissimilar between Northern and Southern European populations. - Our data suggest that the DR2-B8 hp, close to the HLA-B region contain an additive factor affecting susceptibility to Coeliac disease. The MICA5.1, MICB15 and TNF2 (associated to MICBx10) region gives a substantial increase in the odds for the predisposition to the disease. - A novel risk factor, denoted CELIAC2 is located in chromosome 5q31-33 region. This was demonstrated using a meta and mega analysis of the different individual studies carried out by each of the participants with their particular family sets. Although the IL12B locus could be dismissed as the particular genetic factor from the Consortium data, there are several other genes involved in the immunomodulation process linked to this region. Further work is on-going to identify more precisely this genetic factor. - CELIAC3 is another genetic factor clearly identified during this study. It is located in the CTLA4-CD28-ICOS region of chromosome 2q33. It could be identical to the quantitative alteration of CTLA4 expression as shown in other autoimmune diseases as shown recently by the group of Todd. - Other chromosomal regions on chromosome 11q, 15, 16q12 and 19q13 were dismissed. Therefore at least 4 genetic regions are involved with the genotype associated with Celiac disease. The relative weight of each region could be different from one population to the other. Precise identification of the molecules involved in the expression of the disease will be of ultimate importance for confirming the exact importance of each of these regions. Establishment of prevalence of coeliac disease based on serum IgA-class t-Tgase antibody positivity in randomly selected population samples of adults Establishment of prevalence of coeliac disease based on serum IgA-class t-Tgase antibody positivity in randomly selected population samples of adults in 4 different European Member States ( Finland, Germany, Italy and Ireland), and in children in 2 Member States (Ireland and Italy. The aim of the Coeliac-EU Cluster Epidemiology was to establish the prevalence of coeliac disease and tissue transglutaminase antibody positivity in four European countries using a large population-based screening approach. This study confirm the prevalence of coeliac disease in Europe. Average prevalence 1:100. Howerver, the study showed that there are true differences among populations. Coeliac disease is five to ten times less frequent in Germany than in Finland, Italy or Northern Ireland, UK. Validation of the newly developed t-Tgase antibody kits by comparing them to the state of the art endomysial antibody test (EMA test) and choice of the best performing one The aim of the Coeliac-EU Cluster Epidemiology was also to provide new simple serologic diagnostic tests suitable for large population screening programmes. In associated projects the screening tools were further evaluated using the healthy first-degree relatives within multiple case coeliac families as the target. The autoantibody tests were correlated to coeliac disease HLA genetics and an approach to detect IgA deficient individuals was undertaken. Endomysial or tissue transglutaminase autoantibody positivity was confirmed as a specific and sensitive measure of coeliac disease. Indeed project allows the development of tools for clinical case finding by screening and population-based screening programmes. These tools, endomysial and tissue transglutaminase autoantibody serum tests accurately detected clinically silent coeliac disease. The antibody tests correlate with coeliac-type HLA DQ2 and DQ8. Based on the project results, the SEM partner, Eurospital, SpA, has launched two new diagnostic kits on the market, measuring tissue transglutaminase antibodies. Laboratory non-dependent validated screening tools are now available for coeliac disease case finding. Health care professionals are able to identify individuals needing life-long exclusion of wheat, rye, and barley in their daily diet. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
