Spanish national registry of celiac disease: incidence and clinical presentation.

OBJECTIVES: The aim of this study was to assess the incidence and clinical pattern of celiac disease (CD) presently diagnosed in Spanish children. METHODS: A prospective, multicenter, nationwide registry of new cases of CD in children <15 years was conducted from June 1, 2006 to May 31, 2007. The parameters studied were age at diagnosis, sex, clinical symptoms, associated diseases, nutritional status, CD serology, histological lesions, and HLA-DQ2/-DQ8. The crude incidence rate of CD was calculated as new cases per 1000 live births and as new cases per 100,000 person-years <15 years of age. RESULTS: A total of 974 new cases of CD were included. The median age at diagnosis was 2.3 years; 39.5% of CD diagnoses occurred in the first 2 years, 42% between 2 and 6, and 18.4% from 6 to 15. Total number of cases in each age group was 385, 409, and 180, respectively. Regarding clinical presentation 70.9% showed classical symptoms, 21.9% were nonclassical, and 7% were asymptomatic. A total of 95.7% of 931, 94.7% of 611, and 86.7% of 651 children tested positive, respectively, for immunoglobulin A (IgA) anti-transglutaminase type 2 antibodies, IgA endomysial antibodies, and IgA anti-gliadin antibodies. Villous atrophy was observed in 92.4% and increased intraepithelial lymphocytes with crypt hyperplasia in 3.3%. Of the children, 55% had normal growth, and 3.4% were overweight. The HLA phenotype was DQ2: 88.3%, DQ2/DQ8: 8.4%, and DQ8: 2.3%. The incidence rate was 7.9 cases of CD per 1000 live births and 54 cases per 100,000 person-years. CONCLUSIONS: In Spain, the most frequent clinical presentation of CD is the classical form, mainly diagnosed during the first 2 years of life. The observed incidence of CD in Spanish children is much higher than the present CD incidence rates observed in other European countries.

Combined functional and positional gene information for the identification of susceptibility variants in celiac disease.

BACKGROUND & AIMS: Celiac disease is a complex, immune-mediated disorder of the intestinal mucosa with a strong genetic component. HLA-DQ2 is the major determinant of risk, but other minor genes, still to be identified, also are involved. METHODS: We designed a strategy that combines gene expression profiling of intestinal biopsy specimens, linkage region information, and different bioinformatics tools for the selection of potentially regulatory single-nucleotide polymorphisms (SNPs) involved in the disease. We selected 361 SNPs from 71 genes that fulfilled stringent functional (changes in expression level) and positional criteria (located in regions that have been linked to the disease, other than HLA). These polymorphisms were genotyped in 262 celiac patients and 214 controls. RESULTS: We detected strong evidence of association with several SNPs (the most significant were rs6747096, P = 2.38 x 10(-5); rs7040561, P = 6.55 x 10(-5); and rs458046, P = 1.35 x 10(-4)) that pinpoint novel candidate determinants of predisposition to the disease in previously identified linkage regions (eg, SERPINE2 in 2q33, and PBX3 or PPP6C in 9q34). CONCLUSIONS: Our study shows that the combination of function and position is a valid strategy for the genetic dissection of complex traits.

MICA response to gliadin in intestinal mucosa from celiac patients.

MHC class I chain-related gene A (MICA), a putative independent susceptibility gene in autoimmune diseases, encodes a surface protein present in epithelial cells that binds to NKG2D, an activating receptor of NK, alphabeta and gammadelta T cells, and could function as a stress-inducible activator of the innate immune response. There is no evidence of a long-term implication of MICA in the celiac autoimmune process. However, it could be that gliadin activation of MICA occurs only during the initial stages of the disease. In order to determine whether MICA is activated in response to gliadin in patients with celiac disease (CD), small intestinal mucosa biopsy samples from ten long-standing celiac patients on a gluten-free diet and from five non-celiac individuals were incubated with and without gliadin for 4 h. Total RNA was purified and MICA, IFNG and NKG2D mRNA were quantified by fluorescent real-time RT-PCR. Expression levels were calculated relative to GAPDH. MICA expression was detected in both patients and controls, but incubation with gliadin induced a strong increase in samples from the treated CD group compared with the non-CD controls (P=0.028), while no differences were observed for IFNG or NKG2D mRNA levels. The gliadin-provoked over-expression of MICA in "normalized" tissues from CD patients suggests a role for this stress-induced activator of the immune response in the early stages of organ-specific autoimmune destruction, probably preceding the onset of inflammation.

Immunoglobulin G autoantibodies against tissue-transglutaminase. A sensitive, cost-effective assay for the screening of celiac disease.

The characterization of target antigens in several autoimmune disorders has made it possible to develop antigen-specific immunoassays that are superior in terms of sensitivity, specificity, reproducibility and ease of standardization, compared to immunohistological methods that are highly subjective, rely on skilled technicians and are not applicable to large-scale studies. In the case of celiac disease (CD), tissue transglutaminase (tTGase) has been identified as a major autoantigen, and antibodies against this molecule are present in most CD patients before gluten is removed from diet. In general, anti-tTGase detection assays detect the presence of IgA class antibodies, but these immunoglobulins are absent among patients with IgA deficiency, a frequent condition in which CD is very prevalent. In this report, we have analyzed 64 patients at diagnosis of CD for the presence of antibodies against tTGase of both IgA (TGA) and IgG (TGG) classes, using anti-IgA antibodies or Protein A, respectively, for the immunoprecipitation of 35S labeled, in vitro transcribed and translated human recombinant tTGase. In our hands, the TGG assay matches TGA in terms of sensitivity (97%) and specificity (100%), and besides, the combination of both assays is able to detect antibodies in all patient samples. The method described uses only 6 microl of serum, can be adapted to automated large-scale analysis and, in combination with other antigens, can be used for the simultaneous screening of other autoimmune diseases, like type 1 diabetes mellitus.