Advertisement
Mayo Clinic Proceedings Home

New Aspects of the Diagnosis of Celiac Disease in Children, Adolescents, and Adults

      The perception of celiac disease (CD) has changed in the past decade from a rare intestinal disease primarily recognized in childhood to a common, genetically determined disease with autoimmune components that affects people of all ages and involves several organs.
      • Rewers M.
      Epidemiology of celiac disease: what are the prevalence, incidence, and progression of celiac disease?.
      Part of this change has been based on improved diagnostic measures and screening possibilities in the general population and particularly in at-risk populations, such as family members, patients with type 1 diabetes mellitus, and those with autoimmune thyroid disease. Several suggestions for new definitions of CD have recently been published
      • Ludvigsson J.F.
      • Leffler D.A.
      • Bai J.C.
      • et al.
      The Oslo definitions for coeliac disease and related terms.
      • Sapone A.
      • Bai J.C.
      • Ciacci C.
      • et al.
      Spectrum of gluten-related disorders: consensus on new nomenclature and classification.
      • Husby S.
      • Koletzko S.
      • Korponay-Szabo I.R.
      • et al.
      European Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines for the diagnosis of coeliac disease.
      ; complete consensus has as yet not been obtained,
      • Marsh M.N.
      Grains of truth: evolutionary changes in small intestinal mucosa in response to environmental antigen challenge.
      but a framework is apparent (Table 1). All the published definitions agree on the presence of overt CD; silent CD, which is CD without recognized symptoms; and potential CD, which is the presence of CD antibodies and a normal duodenal biopsy result. The diagnostic criteria for CD have changed in practice because of these concepts and technological developments.
      • Ribes-Koninckx C.
      • Mearin M.L.
      • Korponay-Szabo I.R.
      • et al.
      Coeliac disease diagnosis: ESPGHAN 1990 criteria or need for a change? results of a questionnaire.
      The European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) recently developed and launched new ESPGHAN guidelines for the diagnosis of CD.
      • Husby S.
      • Koletzko S.
      • Korponay-Szabo I.R.
      • et al.
      European Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines for the diagnosis of coeliac disease.
      These guidelines not only represent a sea change in thinking about how to reach the diagnosis of CD but also propose, for the first time, basing the diagnosis of an immune disorder largely, if not completely, on serologic tests. This comes at a time when the detection and largely the management of CD increasingly involve general practice. At the same time, the diagnostic algorithms are becoming complicated, necessitating specialized knowledge apart from procedures and biopsies.
      Table 1Clinical Classification of Celiac Disease
      Symptomatic
       Gastrointestinal
       Extraintestinal
      Asymptomatic/silent
      Potential
      (Latent)
      The diagnosis and indeed definition of CD have for decades been based on histologic damage to the small intestine. Previous diagnostic criteria promulgated by ESPGHAN and other organizations, such as the American Gastroenterology Association and a consensus group convened in Europe, pertinent to adults all affirm the necessity of a biopsy for initial diagnosis. In the past, the ESPGHAN criteria also included the need for a follow-up biopsy to show normalization on a gluten-free diet and an additional biopsy after a challenge to prove permanence of the gluten sensitivity that underlies the enteropathy. This approach was at the time necessary because of the differential diagnostic possibilities, particularly infections, in young children. These criteria were modified in children older than 2 years to include only one biopsy.
      Revised criteria for diagnosis of coeliac disease: report of Working Group of European Society of Paediatric Gastroenterology and Nutrition.
      The main change in the 2012 ESPGHAN guidelines is the addition of celiac antibodies and HLA determination as equal in importance to histologic testing in reaching a diagnosis of CD (Table 2). As with every diagnostic test, the selection of patients based on symptoms is important because it defines the pretest probability. Furthermore, the question may be raised that, given this change, how do these modified criteria affect diagnosis worldwide? It is clear that in addition to the patients' symptoms, where the patients live and their ethnicity/race also may affect the likely pretest prevalence of CD, as does the frequency of alternative diagnoses, such as tropical sprue, in certain developing countries, such as India, where CD is also prevalent. The ESPGHAN criteria are forward-looking because these factors are expected to change over time, depending on the results of prospective evaluation of these criteria, and several studies are eagerly awaited.
      Table 2Diagnostic Tools in Celiac Disease
      Clinical symptoms
      Celiac disease–related antibodies (serology)
      HLA-DQ2/DQ8
      Histologic analysis of duodenal biopsy
      Several approaches for analysis of duodenal histologic testing in CD have been advocated, but the grading by Marsh,
      • Marsh M.N.
      Grains of truth: evolutionary changes in small intestinal mucosa in response to environmental antigen challenge.
      later modified by Oberhuber et al
      • Oberhuber G.
      • Granditsch G.
      • Vogelsang H.
      The histopathology of coeliac disease: time for a standardized report scheme for pathologists.
      with subgrades IIIa, b, and c, is the most widely accepted. Marsh grade I is characterized by infiltration by lymphocytes in the epithelium. Immunohistochemical analysis with staining for CD3 may ease the enumeration of the numbers of lymphocytes. Grade II and III delineate increasing grades of villous atrophy. A simpler system based on the presence or absence of villous atrophy and/or total villous atrophy has been promulgated by Corazza et al
      • Corazza G.R.
      • Villanacci V.
      • Zambelli C.
      • et al.
      Comparison of the interobserver reproducibility with different histologic criteria used in celiac disease.
      ; however, despite which system is used, some measure of morphologic analysis and at least quantitation or semiquantitative analysis of the intraepithelial lymphocytosis should be performed. Histologic analysis is only as good as the samples provided. Poorly oriented or inadequately sized samples will not support a diagnosis histologically.
      Thus, the duodenal biopsy may be seen in a more critical light than previously appreciated, and the status of the duodenal biopsy as a reference standard may be questioned for several reasons. First, the histologic changes may be patchy, so different biopsy specimens from different parts of the duodenum may not be uniform. Several biopsy specimens should be taken to make the diagnosis more firm, at least 4 from the second part of the duodenum and at least 1 from the duodenal bulb. Second, histologic interpretation by different pathologists may vary considerably, with only good to moderate κ values.
      • Weile B.
      • Hansen B.F.
      • Hagerstrand I.
      • Hansen J.P.
      • Krasilnikoff P.A.
      Interobserver variation in diagnosing coeliac disease: a joint study by Danish and Swedish pathologists.
      • Corazza G.R.
      • Villanacci V.
      • Zambelli C.
      • et al.
      Comparison of the interobserver reproducibility with different histologic criteria used in celiac disease.
      These comparisons were based on analysis of Marsh subgrades (IIIa-c), so the diagnostic agreement was better for the final diagnosis of CD. In a recent comparison of several laboratories, the agreement of histologic analysis depended on the local interest level.
      • Arguelles-Grande C.
      • Tennyson C.A.
      • Lewis S.K.
      • Green P.H.
      • Bhagat G.
      Variability in small bowel histopathology reporting between different pathology practice settings: impact on the diagnosis of coeliac disease.
      Third, there is no current consensus regarding whether Marsh grade II is sufficient for the diagnosis of CD or whether Marsh grade I only with influx of lymphocytes in the epithelium and no morphologic changes may define CD in the specific biopsy.
      • Kurppa K.
      • Ashorn M.
      • Iltanen S.
      • et al.
      Celiac disease without villous atrophy in children: a prospective study.
      • Walker M.M.
      • Murray J.A.
      An update in the diagnosis of coeliac disease.
      Histologic analysis, although still an important element for the diagnosis of CD, cannot qualify as the unifying criterion standard. Significant attention to quality and inherent biologic variability somewhat tarnish this standard.
      Celiac disease is characterized by a close association to the HLA haplotypes called DQ2 and DQ8, which in contemporary terms are named DQA1*05XX and DQB1*02XX for HLA-DQ2 and DQA1*03XX and DQB1*0302 for HLA-DQ8.
      • Marsh S.G.
      • Albert E.D.
      • Bodmer W.F.
      • et al.
      Nomenclature for factors of the HLA system, 2010.
      Patients with CD primarily harbor these alleles, even though the association may not be 100% but rather 92% to 100%.
      • Hadithi M.
      • von Blomberg B.M.
      • Crusius J.B.
      • et al.
      Accuracy of serologic tests and HLA-DQ typing for diagnosing celiac disease.
      Determination of these HLA haplotypes has been suggested as an additive diagnostic test for CD. However, DQ2 and DQ8 are found in 20% to 30% of healthy whites, giving a high diagnostic specificity but a low sensitivity, so the main role of HLA determination is to exclude CD. Although the association has largely been determined in ethnically homogeneous populations, the possibility for unusual combinations in outbred populations or ethnically missed populations certainly occurs. The strength of the negative predictive value is largely determined by the background prevalence of these genes in the population being tested. For example, the discriminative ability is markedly decreased in family members of people with CD or in individuals with type 1 diabetes, for whom the expected prevalence of genes and gene pairs, including DQ2 and DQ8, is quite high, probably two-thirds or more. In addition, if the gene pairs are included, that is, DQA1*0201 with DQB1*0201, which encodes a haplotype previously termed DQ2.2, or individuals who have DQA*O3XX with DQB1*02XX, then the discriminative ability of the HLA strategy is markedly reduced. Furthermore, the incorporation of HLA in patients who strongly test positive for the tissue transglutaminase (TTG) antibody assumes that these are independent variables. However, it seems to be highly likely that strongly positive TTG antibody or IgA endomysial antibody (EMA) results are likely to occur in DQ2- or DQ8-positive individuals to begin with, so it is not clear whether this strategy actually adds much to the precision. The utility of HLA molecules may rather be in individuals who never had convincing serologic results, either because it was not done or because the patients had already started a gluten-free diet and the results were negative. The price of determination of these HLA alleles has been prohibitively high but has rapidly decreased (2012) to a level comparable to EMA testing. The 2012 ESPGHAN guidelines included HLA determination as a primary step in the testing of risk groups for CD, even though the concrete use of such a strategy is scarce.
      • Hadithi M.
      • von Blomberg B.M.
      • Crusius J.B.
      • et al.
      Accuracy of serologic tests and HLA-DQ typing for diagnosing celiac disease.
      The argument is that the test is not dependent on gluten intake, needs only to be determined once, and gives a final answer when negative. Furthermore, the ESPGHAN guidelines in patients with symptoms suggested HLA as a confirmatory test of exclusion, even though this approach has not been tested in clinical practice. Future studies will reveal whether HLA determination is cost-effective with positive TTG antibody and positive EMA test results.
      The discovery of TTG as the main autoantigen in CD
      • Dieterich W.
      • Ehnis T.
      • Bauer M.
      • et al.
      Identification of tissue transglutaminase as the autoantigen of celiac disease.
      led to the development of assays for serum TTG antibodies of the IgA isotype, which have been shown to be indicative of CD.
      • Rostom A.
      • Dubé C.
      • Cranney A.
      • et al.
      Celiac disease.
      IgA TTG antibodies as determined by enzyme-linked immunosorbent assays or radioimmunossays have in several studies been shown to have a high accuracy.
      • Giersiepen K.
      • Lelgemann M.
      • Stuhldreher N.
      • et al.
      Accuracy of diagnostic antibody tests for coeliac disease in children: summary of an evidence report.
      These tests were only superseded by IgA (EMA), directed against extracellular TTG, a fluorescence-based test with particularly high sensitivity in experienced hands.
      • Salmi T.T.
      • Collin P.
      • Korponay-Szabo I.R.
      • et al.
      Endomysial antibody-negative coeliac disease: clinical characteristics and intestinal autoantibody deposits.
      In general terms, the performance of a particular antibody test in a clinical setting depends on patient characteristics (eg, age, genetic predisposition, and IgA deficiency), pretest probability, stage of the disease, and ingested amounts of gluten. The 2012 ESPGHAN guidelines were based on an evidence report for the diagnosis of CD, which analyzed the literature on CD antibody testing up to 2009.
      • Giersiepen K.
      • Lelgemann M.
      • Stuhldreher N.
      • et al.
      Accuracy of diagnostic antibody tests for coeliac disease in children: summary of an evidence report.
      This analysis referred to the biopsy result as the reference standard for CD. The TTG antibodies had high sensitivity and specificity, however, with a variance heterogeneity, which may be caused by the inclusion of assays based on guinea pig TTG and assays from biosynthesized human TTG. This heterogeneity precluded the calculation of pooled accuracy estimates. However, for 11 of 15 study populations the sensitivity reached more than 90%, and for 13 of 15 study populations specificity reached more than 90%. The EMA test results had the highest diagnostic accuracy, with a diagnostic odds ratio of 533.6 and with particularly high specificities. Data suggest that the greatest significance of EMA testing is not in the highly positive IgA TTG results, because virtually all EMA test results are positive, but in those closer to the negative threshold.
      • Walker M.M.
      • Murray J.A.
      • Ronkainen J.
      • et al.
      Detection of celiac disease and lymphocytic enteropathy by parallel serology and histopathology in a population-based study.
      • Katz K.D.
      • Rashtak S.
      • Lahr B.D.
      • et al.
      Screening for celiac disease in a North American population: sequential serology and gastrointestinal symptoms.
      A thorough analysis based on ring testing in a number of laboratories and several test serum samples of radioimmunoassays for TTG antibodies
      • Li M.
      • Yu L.
      • Tiberti C.
      • et al.
      A report on the International Transglutaminase Autoantibody Workshop for Celiac Disease.
      indicated that methodologic quality may be improved. It may be concluded that the accuracy of TTG antibody determination seems to be high, but the algorithm for CD diagnosis puts considerable demands on TTG antibody assay quality, necessitating assay uniformity and quality control measures that may not be fulfilled at present.
      • Egner W.
      • Shrimpton A.
      • Sargur R.
      • Patel D.
      • Swallow K.
      ESPGHAN guidance on coeliac disease 2012: multiples of ULN for decision making do not harmonise assay performance across centres.
      However, taken together these data are promising and led to the suggestion in the ESPGHAN guidelines that the biopsy may be omitted in selected patients with high TTG antibody levels supplemented by positive EMA test results and HLA typing negative for DQ2 and DQ8.
      Different pretest probabilities significantly influence the resulting predictive diagnostic value. The pretest probability relies on the clinical symptoms because clear symptoms lead to higher pretest probability, again leading to higher posttest probability; this highlights the importance of proper clinical judgment. For symptomatic patients the pretest probability of CD may be 10%, whereas the pretest probability for population screenings may be 0.5% to 1.0%. In the United States currently, somewhere between 1.5% and 2% of adults undergoing small biopsies for suspected CD actually turn out to have CD as diagnosed by biopsy. The rate of positive serologic test results in reference laboratories probably approximates 3%. This finding would suggest that pretest probability of most clinical circumstances is much lower than 50% anticipated in an individual with frank malabsorption and perhaps a family history of CD. The ESPGHAN guidelines discuss the omission of biopsies for CD diagnosis only in the testing of clearly symptomatic patients with presumed pretest probabilities of approximately 10% and thus with fairly high positive predictive values. Omission of biopsy is not recommended for patients identified on screening, whether in the general population or in selected populations.
      The likelihood of an accurate and timely diagnosis of CD has improved considerably during the past decade, and the new ESPGHAN guidelines may give an impetus for further developments. The accuracy of TTG antibody assays for the diagnosis of CD in general is high, and HLA determinations are now feasible in the clinical routine. Further technological developments undoubtedly will increase diagnostic accuracy, and large, preferably multicenter clinical trials will be needed to test these new possibilities.

      Supplemental Online Material

      References

        • Rewers M.
        Epidemiology of celiac disease: what are the prevalence, incidence, and progression of celiac disease?.
        Gastroenterology. 2005; 128: S47-S51
        • Ludvigsson J.F.
        • Leffler D.A.
        • Bai J.C.
        • et al.
        The Oslo definitions for coeliac disease and related terms.
        Gut. 2013; 62: 43-52
        • Sapone A.
        • Bai J.C.
        • Ciacci C.
        • et al.
        Spectrum of gluten-related disorders: consensus on new nomenclature and classification.
        BMC Med. 2012; 10: 13
        • Husby S.
        • Koletzko S.
        • Korponay-Szabo I.R.
        • et al.
        European Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines for the diagnosis of coeliac disease.
        J Pediatr Gastroenterol Nutr. 2012; 54: 136-160
        • Marsh M.N.
        Grains of truth: evolutionary changes in small intestinal mucosa in response to environmental antigen challenge.
        Gut. 1990; 31: 111-114
        • Ribes-Koninckx C.
        • Mearin M.L.
        • Korponay-Szabo I.R.
        • et al.
        Coeliac disease diagnosis: ESPGHAN 1990 criteria or need for a change? results of a questionnaire.
        J Pediatr Gastroenterol Nutr. 2012; 54: 15-19
      1. Revised criteria for diagnosis of coeliac disease: report of Working Group of European Society of Paediatric Gastroenterology and Nutrition.
        Arch Dis Child. 1990; 65: 909-911
        • Oberhuber G.
        • Granditsch G.
        • Vogelsang H.
        The histopathology of coeliac disease: time for a standardized report scheme for pathologists.
        Eur J Gastroenterol Hepatol. 1999; 11: 1185-1194
        • Weile B.
        • Hansen B.F.
        • Hagerstrand I.
        • Hansen J.P.
        • Krasilnikoff P.A.
        Interobserver variation in diagnosing coeliac disease: a joint study by Danish and Swedish pathologists.
        APMIS. 2000; 108: 380-384
        • Corazza G.R.
        • Villanacci V.
        • Zambelli C.
        • et al.
        Comparison of the interobserver reproducibility with different histologic criteria used in celiac disease.
        Clin Gastroenterol Hepatol. 2007; 5: 838-843
        • Arguelles-Grande C.
        • Tennyson C.A.
        • Lewis S.K.
        • Green P.H.
        • Bhagat G.
        Variability in small bowel histopathology reporting between different pathology practice settings: impact on the diagnosis of coeliac disease.
        J Clin Pathol. 2012; 65: 242-247
        • Kurppa K.
        • Ashorn M.
        • Iltanen S.
        • et al.
        Celiac disease without villous atrophy in children: a prospective study.
        J Pediatr. 2010; 157 (380.e371): 373-380
        • Walker M.M.
        • Murray J.A.
        An update in the diagnosis of coeliac disease.
        Histopathology. 2011; 59: 166-179
        • Marsh S.G.
        • Albert E.D.
        • Bodmer W.F.
        • et al.
        Nomenclature for factors of the HLA system, 2010.
        Tissue Antigens. 2010; 75: 291-455
        • Hadithi M.
        • von Blomberg B.M.
        • Crusius J.B.
        • et al.
        Accuracy of serologic tests and HLA-DQ typing for diagnosing celiac disease.
        Ann Intern Med. 2007; 147: 294-302
        • Dieterich W.
        • Ehnis T.
        • Bauer M.
        • et al.
        Identification of tissue transglutaminase as the autoantigen of celiac disease.
        Nat Med. 1997; 3: 797-801
        • Rostom A.
        • Dubé C.
        • Cranney A.
        • et al.
        Celiac disease.
        Evid Rep Technol Assess (Summ). 2004; : 1-6
        • Giersiepen K.
        • Lelgemann M.
        • Stuhldreher N.
        • et al.
        Accuracy of diagnostic antibody tests for coeliac disease in children: summary of an evidence report.
        J Pediatr Gastroenterol Nutr. 2012; 54: 229-241
        • Salmi T.T.
        • Collin P.
        • Korponay-Szabo I.R.
        • et al.
        Endomysial antibody-negative coeliac disease: clinical characteristics and intestinal autoantibody deposits.
        Gut. 2006; 55: 1746-1753
        • Walker M.M.
        • Murray J.A.
        • Ronkainen J.
        • et al.
        Detection of celiac disease and lymphocytic enteropathy by parallel serology and histopathology in a population-based study.
        Gastroenterology. 2010; 139: 112-119
        • Katz K.D.
        • Rashtak S.
        • Lahr B.D.
        • et al.
        Screening for celiac disease in a North American population: sequential serology and gastrointestinal symptoms.
        Am J Gastroenterol. 2011; 106: 1333-1339
        • Li M.
        • Yu L.
        • Tiberti C.
        • et al.
        A report on the International Transglutaminase Autoantibody Workshop for Celiac Disease.
        Am J Gastroenterol. 2009; 104: 154-163
        • Egner W.
        • Shrimpton A.
        • Sargur R.
        • Patel D.
        • Swallow K.
        ESPGHAN guidance on coeliac disease 2012: multiples of ULN for decision making do not harmonise assay performance across centres.
        J Pediatr Gastroenterol Nutr. 2012; 55: 733-735