Diagnosing celiac disease: a comparison of human tissue transglutaminase antibodies with antigliadin and antiendomysium antibodies

OBJECTIVE: To evaluate and compare the sensitivity and specificity of the new serologic marker human antitissue transglutaminase antibodies (IgA anti-tTG) with those of antiendomysium (IgA EMA) and antigliadin antibodies (IgA and IgG AGA) for the diagnosis of celiac disease (CD). METHODS: The level of IgA antibodies to tTG in serum was determined by an enzyme-linked immunosorbent assay (ELISA) test using recombinant human tTG as the antigen; IgA EMA, by indirect immunofluorescence; and IgA and IgG AGA, by ELISA. Sixty-eight serum samples from 59 patients with CD were studied-30 patients had untreated CD, 22 were on gluten-free diets, and 16 had been reintroduced to gluten-and compared with serum samples from 116 children examined for failure to thrive, short stature, various digestive diseases, or other non-CD conditions. RESULTS: Twenty-eight of 30 patients with CD had anti-tTG (the 2 patients whose results were negative were 1 patient with IgA deficiency and 1 infant); 27 of 30 patients had IgA EMA (1 child was IgA anti-tTG positive and IgA EMA negative); 18 of 30 had IgA AGA; and 28 of 30 had IgG AGA. On gluten-free diets, 4 of 22 patients had anti-tTG but none had IgA EMA or IgA AGA. On normal diets, 15 of 15 children who had relapsed had anti-tTG; 9, IgA EMA; 4, IgA AGA; and 8, IgG AGA (1 child did not relapse). In subjects without CD, 3 of 116 had anti-tTG; 12, IgG AGA; and 1, IgA AGA, but none had IgA EMA. In the 3 children who had anti-tTG, CD could be excluded. The positive predictive value of IgA anti-tTG was 90% and the negative predictive value, 98%. In comparison, results for IgA EMA were 100% and 97%, IgA AGA 94% and 90%, and IgG AGA 70% and 98%, respectively. CONCLUSION: The presence of human anti-tTG is a reliable indicator for the diagnosis and follow-up of CD.     

Antibody reactivity against human and guinea pig tissue transglutaminase in children with celiac disease

BACKGROUND: Highly discriminatory markers for celiac disease are needed to identify children with early mucosal lesions. The purposes of this study were to evaluate the clinical potential of circulating anti-tissue transglutaminase (tTG) immunoglobulin (Ig)A antibodies in the diagnosis of childhood celiac disease and to investigate the extent of autoreactivity of these antibodies. METHODS: Included in this retrospective study were samples from 22 children with biopsy-verified celiac disease, 23 control subjects with disease, and 22 healthy control subjects without any known gastrointestinal or inflammatory disorders. An enzyme-linked immunosorbent assay (ELISA) was used to measure the serum levels of IgA antibodies specific for human and guinea pig tTGs. All samples were also analyzed for antibodies to gliadin and endomysium (EMA). RESULTS: The concentrations of IgA specific for human and guinea pig tTGs correlated with the small intestinal villous structure and the serum levels of IgA EMA. The tTG ELISAs exhibited a high specificity and sensitivity for detection of untreated celiac disease. The human erythrocyte IgA tTG ELISA had the highest sensitivity (100%) and a specificity of 98%. The IgA EMA method had a sensitivity of 95% and the highest specificity (100%) of all tests. CONCLUSIONS: Our results provide additional support to the concept that anti-tTG IgA antibodies can be used as a highly discriminatory serologic marker for celiac disease and that measurements of these autoreactive antibodies may in the future be used as an alternative to the EMA test.     

Antitissue transglutaminase and antithyroid autoantibodies in children with Down syndrome and celiac disease

OBJECTIVES: We measured circulating autoantibodies and evaluated the potential of circulating antitissue transglutaminase (tTG) antibodies to determine the presence of celiac disease (CD) in children with Down syndrome. METHODS: An ELISA based on recombinant human tTG was used to measure the levels of immunoglobulin A and immunoglobulin G antibodies in serum samples from 72 children with Down syndrome, 52 children with biopsy-verified CD, 21 disease controls with a normal small intestinal mucosa and 23 healthy controls. Of the 72 Down syndrome children, 11 under-went a small intestinal biopsy. RESULTS: Four of 72 children with Down syndrome were diagnosed as having CD and three of them had serum levels of immunoglobulin A tTG antibodies greater than 6 U/mL (668, 147 and 7 U/mL). One Down syndrome child with biopsyproven CD had normal levels of immunoglobulin A tTG. Two Down syndrome children had increased levels of immunoglobulin A tTG (13 and 7 U/mL) but none of these children had an intestinal biopsy performed. Of the 52 CD subjects (median 664 U/mL) one was negative for immunoglobulin A tTG (5 U/mL) and all healthy controls (median 1.2 U/mL) and disease controls (median 0.9 U/mL) had immunoglobulin A tTG antibody levels less than 6 U/mL. Two of four Down syndrome children with CD and 36 of 52 celiac children had increased serum levels of immunoglobulin G tTG antibodies. There was no correlation between the serum levels of tTG and antithyroid autoantibodies. CONCLUSIONS: Although the diagnosis of CD depends on histologic evaluation of intestinal biopsies, detection of anti-tTG antibodies provides a useful complementary diagnostic method for CD in children with Down syndrome.     

Prediction of silent celiac disease at diagnosis of childhood type 1 diabetes by tissue transglutaminase autoantibodies and HLA

Abstract: Aims: The aims were to estimate the diagnostic sensitivity and specificity of autoantibodies to tissue transglutaminase (IgA‐ and IgG‐tTG), gliadin (AGA) and endomysium (EMA) in relation to human leukocyte antigen (HLA)‐DQB1 alleles to identify silent celiac disease at diagnosis of type 1 diabetes. Methods: IgA‐ and IgG‐tTG were measured in radioligand binding assays in 165 type 1 diabetic patients. Data on HLA‐DQB1 were available for 148 patients and on both AGA and EMA for 164 patients. For patients considered positive for AGA or EMA, or both, an intestinal biopsy was suggested. HLA‐DQB1 typing was carried out by polymerase chain reaction and hybridization with allele specific probes. Results: Three patients, left out from further study of antibodies, but not from HLA‐DQB1 analysis, had treated celiac disease at diagnosis. Out of the other 162 type 1 diabetic patients tested, nine had IgA‐tTG, six IgG‐tTG, eight EMA, and 11 AGA. Biopsy was suggested for nine patients, of whom six showed villous atrophy, one did not and two refused to participate. Thus, silent celiac disease was probable in 8/162 and biopsy‐verified in 6/162, where five patients were AGA‐positive and six either EMA‐, IgA‐tTG‐ or IgG‐tTG‐positive. Of the 11 patients with celiac disease (three with treated and eight with silent celiac disease), 10 were HLA‐DQB1‐typed, of whom 65% (13/20) had the DQB1*02 allele, compared with 36% (100/276; p = 0.011) of those without celiac disease. IgA‐tTG levels were higher in patients having either *02 or *0302 (0.6; ?1.3–112.4 RU) compared with those not having these alleles (0.4; ?0.7–3.4 RU; p = 0.023). Conclusion: IgA‐tTG are HLA‐DQB1*02‐associated autoantibodies with high sensitivity and specificity for silent celiac disease at diagnosis of type 1 diabetes.     

Human recombinant tissue-transglutaminase antibodies: evaluation of a commercial kit and comparison of methods using guinea pig antigen

AIM: The tissue-Trans-Glutaminase (t-TG) has been reported to be the target for endomysial antibodies in coeliac disease. Coeliac disease if untreated, although clinically silent, predispose for other autoimmune disease, large scale screening methods are needed for an early diagnosis. The recently introduced ELISA methods to detect tTG antibodies, that used as antigen Guinea Pig tissue transglutaminase provide an efficient alternative to the anti-endomysial (EMA) immunofluorescent method and are suitable for screening. Our aim was to compare the commercial kit utilizing tTG from guinea pig (GP-tTG) to the standard method that we developed in our laboratory and with the new method that employed human recombinant tTG (hr-tTG). METHODS: We tested serum samples from 16 untreated celiac patients, 10 coeliac patients in gluten free diet, 22 subjects with other disease and 32 healthy controls, for a total number of 80 sera, with 3 commercial kit which employed GP-tTG and 1 that employed hr-tTG, as reference method we used an ELISA method developed in our laboratory and the immunofluorescence method to detect EMA. RESULTS: Results show that methods employing human tTG had a sensibility of 100% with a specificity of 98% and a predictive value of 94%, instead methods employing GP-tTG show inferior results. CONCLUSION. We conclude that is better using hr-tTG as antigen in screening methods for coeliac disease.     

Antibodies to gliadin, endomysium, and tissue transglutaminase for the diagnosis of celiac disease.

BACKGROUND: Tissue transglutaminase has recently been identified as the main autoantigen recognized by antiendomysial antibodies in celiac disease. Serum immunoglobulin (Ig)A antibodies to tissue transglutaminase (tTG-ab) determined by an enzyme-linked immunosorbent assay (ELISA) technique have been reported to correlate closely with IgA antiendomysial antibodies (EMA). The purpose of this study was to assess the sensitivity, specificity, and predictive value of tTG-ab measured by a commercially available ELISA technique, compared with those of EMA and IgA antigliadin antibodies (AGA) for the diagnosis of celiac disease. METHODS: Twenty-seven serum samples were obtained from patients with untreated celiac disease, 37 from patients who had had gluten withdrawn from their diets for varying time spans, and 34 from control subjects without celiac disease. All were younger than 14 years. Presence of tTG-ab and AGA was determined by ELISA and of EMA by indirect immunofluorescence. RESULTS: Twenty-six of 27 serum samples obtained from patients at the time of diagnosis of celiac disease were AGA positive. All 27 (concordance rate 100%) were positive for EMA and tTG-ab. Of the 34 control subjects, 1 was for AGA and 2 for tTG-ab. All 34 were negative for EMA. Sensitivity, specificity, positive predictive value, and negative predictive value within this group were, for tTG-ab: 100%, 94%, 93%, and 100%, respectively; for EMA: all four indexes were 100%; and for AGA: 96%, 97%, 96%, and 97%, respectively. Of the 37 with treated celiac disease, 2 were AGA positive, 9 were EMA positive, and 6 were tTG-ab positive. The concordance rate between EMA and tTG-ab was 100% in the group with untreated celiac disease, 94% in the control subjects, and 76% in the group with treated celiac disease. CONCLUSIONS: Immunoglobulin A antibodies to tissue transglutaminase are new, highly sensitive, and specific markers of celiac disease. They can be determined easily by an accurate, comparatively cheap technique and thereby may advantageously replace the EMA marker traditionally used.     

Tissue transglutaminase immunoglobulin isotypes in children with untreated and treated celiac disease

OBJECTIVES: Tissue transglutaminase (tTG) autoantibodies are serologic markers for celiac disease (CD). The aim was to determine the diagnostic sensitivity and specificity of different immunoglobulin isotypes against tTG. METHODS: Immunoglobulin A (IgA)-tTG, IgG-tTG, and IgG1-tTG were measured in radioligand binding assays in 67 children with untreated and 89 children with treated CD and compared with 48 biopsy controls. IgM-tTG was measured in children with untreated CD and in biopsy controls. IgA endomysial autoantibodies (EMA) were analyzed in all children using an immunofluorescence method. RESULTS: The sensitivity of IgA-tTG and IgG-tTG was 85.1% (57 of 67) and 83.6% (56 of 67), respectively, which both increased to 93.8% (45 of 48) in children diagnosed at age 2 years or older. Both had a specificity of 93.8% (45 of 48). IgA-EMA had a sensitivity of 80.6% (54 of 67) and a specificity of 91.7% (44 of 48). In treated CD, IgA-tTG and IgG-tTG were detected in 21.3% (19 of 89) and in 14.6% (13 of 89), respectively, despite negative EMA titers. IgG1-tTG was correlated to age (r = -0.47, P = 0.0005) and detected in 50.7% (34 of 67) with untreated CD compared with 11.2% (10 of 89) with treated CD and with 4.2% (2 of 48) of biopsy controls ( P < 0.0001, respectively). IgM-tTG was detected in 1.5% (1 of 67) with untreated CD and in none of biopsy controls. CONCLUSION: IgA-tTG and IgG-tTG analyzed in radioligand binding assays are equivalent to IgA-EMA as screening tests for CD during childhood, but an intestinal biopsy is still the method of choice to establish the diagnosis. Although IgG1-tTG was more common at young age of diagnosis, both IgG1-tTG and IgM-tTG had low specificity and sensitivity and may not be useful as screening tests for CD.     

Serum IgA and IgG gliadin antibodies and small intestinal mucosal damage in children

Serum immunoglobulin (Ig) A and IgG gliadin antibodies were determined with a simple, rapid, and inexpensive method--diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA)--and the results were related to small intestinal mucosal morphology in 234 children suspected of having malabsorption. Fifty-six of 58 children with flat intestinal mucosa had increased IgA and/or IgG gliadin antibody levels (sensitivity 97%). Fifty-four of the 58 children had celiac disease (CD) (n = 25) or probable CD (n = 29). Four children with flat mucosa had cow's milk protein and/or soy protein intolerance and three of these had increased gliadin antibody levels. Seventeen percent of 132 children with normal intestinal mucosa had increased IgA and/or IgG gliadin antibody levels. IgA and IgG gliadin antibody levels decreased significantly in the celiac children on a gluten-free diet and increased significantly after gluten challenge. Determination of serum IgA and IgG gliadin antibodies by means of DIG-ELISA is a sensitive test for small intestinal mucosal damage in children. When malabsorption is suspected, we suggest that this assay be used to select children for a small intestinal biopsy. It is also very useful for the follow-up of adherence to a gluten-free diet and to determine the effect of gluten challenge in celiac children.     

Autoantibodies against soluble and immobilized human recombinant tissue transglutaminase in children with celiac disease

OBJECTIVES: The conformation of tissue transglutaminase might influence the performance of immunoassays to detect autoantibodies from patients with celiac disease. The present study investigated how the exposure of tissue transglutaminase kept in a liquid phase and fixed to a solid support affected the binding of immunoglobulin (Ig)A and IgG autoantibodies in children with untreated and treated celiac disease. METHODS: Included were 73 untreated celiac disease children, 50 controls and 80 children with treated celiac disease. IgA and IgG antitissue transglutaminase were measured with solid phase enzyme-linked immunoassay (ELISA) and liquid phase radioligand binding assays. For IgG antitissue transglutaminase detection with radioligand binding assays antihuman IgG and protein A were used. IgA endomysial autoantibodies were measured by indirect immunofluorescence. RESULTS: Both ELISA and radioligand binding assays detected IgA antitissue transglutaminase in 65 of 73 untreated celiac disease children and in 2 of 50 controls. One additional control child was detected with radioligand binding assays. Endomysial autoantibodies were present in 62 of 73 celiac disease children and in 2 of 50 controls. IgG antitissue transglutaminase was detected with both ELISA and radioligand binding assays in 40 of 73 untreated celiac disease children and in 2 of 50 controls. Radioligand binding assays using protein A detected 20 of 73 additional untreated celiac disease children and one control child with increased IgG antitissue transglutaminase. In treated celiac disease children, 21 of 80 were IgA antitissue transglutaminase positive with radioligand binding assays, 3 of 80 with ELISA, whereas none had endomysial autoantibodies. CONCLUSIONS: No qualitative differences between radioligand binding assays and ELISA in IgA or IgG antitissue transglutaminase binding from untreated celiac disease children was demonstrated. However, discrepancies in the binding of IgA antitissue transglutaminase from a subgroup of treated celiac disease children indicated that alterations of tissue transglutaminase might occur on fixation of the antigen. Protein A used for radioligand binding assays seemed not to assess IgG autoantibodies exclusively. IgA antitissue transglutaminase detection in screening of childhood celiac disease can be performed either by ELISA or radioligand binding assays because the two assays are interchangeable.     

Celiac disease diagnosis in misdiagnosed children

Antiendomysial antibodies (EMA) are today considered the most sensitive and specific serological marker of celiac disease (CD). The aim of the present study was to assess the occurrence of EMA of IgG isotype in EMA IgA negative children with clinical suspicion of malabsorption and their relationship with CD. Serum EMA IgG1 determination was performed on 30 EMA IgA negative children with clinical suspicion of CD. Total serum IgA levels were further investigated. Sixty children with gastroenterological diseases other than CD were used as control disease patients and 63 healthy children were evaluated as the control group. Eighteen out of 30 children in the study showed EMA IgG1 positivity in sera and a villous height/crypt depth ratio <3:1 as index of intestinal atrophy. It is noticeable that a selective IgA deficiency was present in only 9 of 18 EMA IgG1 positive children. In addition, clinical symptoms, EMA IgG1, and mucosal atrophy disappeared after 8-10 mo on a gluten-free diet. Neither EMA IgA nor EMA IgG1 were detected in the children in the control groups. The other 12 children in study group showed no histologic abnormalities and were EMA IgG1 negative. In this study, we reveal a group of EMA IgG1 CD children without IgA deficiency. The diagnosis was based on the presence of gluten-dependent typical serological and histologic features of CD. Our data suggest that EMA IgG1 determination could be a new tool in the diagnostic workup of CD, useful in avoiding possible misdiagnosis.     

Patchy villous atrophy of the duodenum in childhood celiac disease

OBJECTIVES: Patchy villous atrophy of the duodenal mucosa has been described in adults with untreated celiac disease (CD) but not in children. The authors evaluated the presence and the distribution of villous atrophy in children with celiac disease to see whether this histologic pattern exists in children. METHODS: We studied 95 children at diagnosis (Group 1) and seven during gluten challenge (Group 2). We measured anti-endomysium antibodies (EMA) by immunofluorescence on monkey esophagus, antihuman-tissue transglutaminase autoantibodies (anti-tTG Abs) by radioimmunoprecipitation, and HLA-DQ2/DQ8 heterodimers by polymerase chain reaction using specific primers. During upper intestinal endoscopy, at least five duodenal biopsy samples were obtained, one from the duodenal bulb and four from the distal duodenum. RESULTS: Thirteen of 95 (13.7%) patients in Group 1 and in 3 of 7 (42.9%) in Group 2 had patchy villous atrophy of the duodenum. In all 16 patients, villous atrophy of the bulb was present. In four children from Group 1, villous atrophy was observed only in the bulb samples. EMA, anti-tTG Abs, and HLA-DQ2/DQ8 heterodimers were present in all patients. Fourteen of 16 had symptomatic CD, and two were silent, detected during screening in subjects at risk for CD. CONCLUSIONS: This is the first study demonstrating that children with CD may have patchy villous atrophy of the duodenum. The bulb mucosa may be the only duodenal area involved, both at diagnosis and after gluten challenge. Therefore, multiple endoscopic biopsies should always be performed, not only in the distal duodenum, but also in the bulb.     

Celiac disease in relation to immunologic serum markers, trace elements, and HLA-DR and DQ antigens in Swedish children with Down syndrome.

BACKGROUND: An association between Down syndrome and celiac disease has been reported. This study was conducted to determine the association between childhood celiac disease and Down syndrome in the county of Uppsala, Sweden. METHODS: All 76 children with Down syndrome (1-18 years) were screened for the occurrence of anti-gliadin antibodies (AGA) and anti-endomysium antibodies (EMA). Twelve children with suspected celiac disease were investigated further. RESULTS: Increased levels of both IgA and IgG AGA were found in 26% of the children and of EMA in and 5 of 76. Celiac disease was diagnosed in at least three of the children (3.9%; 95% confidence interval 0%-8.3%), and it could have been present in as many as eight. Three of the five EMA-positive children with suspected celiac disease had the HLA phenotype DR3, DQ2. CONCLUSIONS: The results show that determination of EMA is more useful as a screening test for celiac disease and for follow-up than is AGA in children with Down syndrome. The present study also confirms that celiac disease is overrepresented among Swedish children with Down syndrome and that celiac disease should be considered in all persons with Down syndrome.     

Antibodies to gliadin by ELISA as a screening test for childhood celiac disease

The sera of 309 children who were subjected to jejunal biopsy were tested for antigliadin antibodies (AGA) with enzyme-linked immunosorbent assay (ELISA) in order to evaluate the usefulness of this test as a screening test for childhood celiac disease (CD). Thirty-one children had flat intestinal mucosa later confirmed to be due to CD. Ninety percent of these children had significantly elevated levels of IgA class AGA and 94% had significantly elevated levels of IgG class AGA as compared to standard references. Two hundred and seventy-eight children had normal villous structure. In this group, 37 children out of 271 (seven excluded because of selective IgA deficiency) had elevated levels of IgA class AGA, and 93 children out of 278 had elevated levels of IgG class AGA. We conclude that ELISA-AGA is suitable as a screening test for childhood CD.     

Serum antibodies to dietary antigens: a prospective study of the diagnostic usefulness in celiac disease of children

We examined 1,541 consecutive serum samples from 707 children with suspected food intolerance and 32 with treated celiac disease (CD) for IgG and IgA antibody reactivities to antigens from gluten, egg, and cow's milk by an enzyme-linked immunosorbent assay (ELISA). Samples from 72 patients showed increased IgA and/or IgG reactivity to gluten antigens; four were known CD patients not complying with a gluten-free diet, 13 were suspected CD patients challenged with gluten, and 30 most likely had CD as suggested by small intestinal villous atrophy and histological and/or clinical improvement on a gluten-free diet. The remainder with increased antigluten activity had other disorders that might have affected mucosal permeability. Nevertheless, the median IgA reactivity to gluten was significantly higher in the CD group, and the probability for CD increased from 25 to 100% when this reactivity was above 2.4 optical density (OD) units in our ELISA. Sixteen CD patients (but none of those without CD) had IgA reactivity to gluten higher than 2.4 OD units. We conclude that ELISA determinations of levels of serum antibodies reacting to dietary antigens is a valuable adjunct in the diagnosis of CD in children.     

A comparison between antigliadin antibodies and blood xylose in celiac disease]

We have compared serum antigliadin antibodies (AGA) with xylose absorption test in diagnosis and follow-up of pediatric celiac disease. Three groups of children were investigated: celiacs, affected by other gastrointestinal disease, healthy controls. On gluten diet AGA IgA, IgG and xylose test were abnormal in all celiac children. After only three months of gluten-free diet, abnormal AGA IgA values were found in 3%, AGA IgG in 63%, xylose test in 28% of children. Normal values for AGA IgA and IgG and for xylose test were found between 7 and 20 months. On challenge, after 1-4 months of gluten diet, abnormal AGA IgA and IgG values were found in 90% of cases, xylose test only in 27%. As far as the children with other gastrointestinal disease are concerned, 2% had abnormal values for AGA IgA, 22% for AGA IgG and 42% for xylose test. All healthy children had normal AGA IgA, IgG values and xylose test. Our date show AGA IgA the most specific laboratory test, among these investigated, for diagnosis and follow-up of celiac disease.     

Antiendomysium antibodies and coeliac disease: solved and unsolved questions. An Italian multicentre study

A total of 3783 subjects were enrolled to compare IgA and IgG gliadin antibodies (AGA) with IgA endomysium antibodies (EMA) in coeliac disease (CD). Among 688 children with untreated CD EM A were positive in 93.8%, IgA AGA in 84.9% and IgG AGA in 90.2%. AGA, but not EMA, sensitivity decreased with age. EMA were present in 3.8% of control subjects, IgA AGA in 14.9% and IgG AGA in 34.3%. Follow-up of 5 of 39 EMA-positive controls showed flat mucosa. Combined determination of EMA and AGA showed an increased predictive value: if EMA and AGA were both positive, the mucosa was flat in 99.1%, if both were negative, the mucosa was normal in 99.1%. After a gluten-free diet (GFD), IgA-AGA disappeared first. Among 21 patients not on a strict GFD and in 194 coeliac patients after challenge, EMA, but not AGA, were always positive. Among 67 first-degree relatives of coeliacs, the positive predictive value of EMA was 90.6%, IgA AGA 74.3% and IgG AGA 44.6%. In conclusion, EMA screening is an excellent test for the diagnosis and follow-up of CD, and for identification of its silent and latent forms. Antiendomysium antibodies, coeliac disease     

Tissue transglutaminase autoantibodies and human leucocyte antigen in Down's syndrome patients with coeliac disease

The association between autoantibodies against tissue transglutaminase (tTG) and human leucocyte antigen (HLA)-DQB1 alleles was tested in Down's syndrome (DS) patients with and without coeliac disease (CD). Immunoglobulin A (IgA) and G (IgG) anti-tTG were measured in radioligand binding assays and compared with conventionally analysed IgA antibodies against gliadin (AGA) and IgA autoantibodies against endomysium (EMA) in 48 DS patients. HLA-DQB1 typing was carried out by polymerase chain reaction and hybridization with allele-specific probes in 41/48 patients. Both IgA-tTG and IgG-tTG, as well as EMA, were detected in 7/48 and AGA in 15/48 patients. Intestinal biopsy showed histopathological changes consistent with CD in 9/16 patients. HLA-DQB1 typing, available for 8/9 patients with and for 33/39 without CD, demonstrated that 5/8 with CD had DQB1*02 compared with 7/33 of those without ( p = 0.0345). In patients with anti-tTG, 5/6 had the DQB1*02 allele compared with 7/35 of those without ( p = 0.0053).

Conclusions: Anti-tTG are HLA-DQB1*02-associated autoantibodies which together could be useful screening tests for silent CD in DS patients. In patients with gastrointestinal symptoms or clinical signs of malabsorption, anti-tTG should be combined with AGA to detect other forms of enteropathies and CD.     

Gliadin-specific serum immunoglobulins A, E, G, and M in childhood: relation to small intestine mucosal morphology

An enzyme-linked immunosorbent assay technique was developed to determine serum antigliadin antibodies of the IgA, IgE, IgG, and IgM classes. The antibody level of each serum specimen was expressed as an index value, i.e., optical density of test serum/optical density of cutoff, where cutoff was calculated for each immunoglobulin class as the mean + 3 SD for six healthy controls. Indices for each immunoglobulin class were determined in 69 children who were admitted for their first small intestinal mucosal biopsy due to either symptoms of malabsorption compatible with celiac disease, or short stature without other symptoms. Especially raised levels of antigliadin IgA antibodies in serum correlated strongly with villous atrophy and in infants less than or equal to 3 years of age were invariably elevated above controls, provided they were on a gluten-containing diet. Raised levels of IgG and IgE antibodies to gluten were often seen in children with normal mucosal morphology, i.e., when symptoms were due to other gastrointestinal disorders than celiac disease. It is concluded that determination of antigliadin IgA antibodies in children less than or equal to 3 years is a useful screening test before small intestinal biopsy, especially in children where the indication for biopsy is not otherwise obvious. The method can also be used to assess the results of therapy and, conceivably, compliance.     

Human tissue transglutaminase enzyme linked immunosorbent assay outperforms both the guinea pig based tissue transglutaminase assay and anti-endomysium antibodies when screening for coeliac disease

Anti-endomysium antibodies (EMA) and antigliadin antibodies (AGA) are widely used when screening for coeliac disease (CD), although their specificity and sensitivity are suboptimal. The guinea pig tissue transglutaminase (tTG) assay also did not prove to be superior. A newly developed enzyme linked immunosorbent assay (Celikey), based on human tTG, might however have a better performance. We therefore investigated the sensitivity and specificity of this human IgA tTG assay in 101 patients with aspecific gastrointestinal complaints and compared this to guinea pig IgA tTG, AGA and EMA. A total of 52 patients with CD were investigated and 49 patients without CD. All had a small bowel biopsy. Our results showed that human IgA tTG had a sensitivity of 96% and a specificity of 100%. Guinea pig IgA-tTG had a sensitivity of 96% and a specificity of 92%. EMA had a sensitivity of 92% and a specificity of 90%. Both IgA AGA and IgG AGA had a sensitivity of 83% whilst having a specificity of 86% and 80% respectively. CONCLUSION: both the human IgA tissue transglutaminase enzyme linked immunosorbent assay and the guinea pig IgA tissue transglutaminase assay could better identify patients with coeliac disease than IgA anti-endomysium antibodies. Although in a larger series of control patients the specificity for the human IgA tissue transglutaminase enzyme linked immunosorbent assay might fall below 100%, in our opinion this is currently the serological method of choice in identifying patients with coeliac disease in the absence of IgA deficiency.     

Short stature as the primary manifestation of monosymptomatic celiac disease.

It is generally accepted that celiac disease (CD) must always be taken into consideration when dealing with children manifesting growth failure. It is therefore important to have laboratory tests capable of detecting patients who should undergo intestinal biopsy. Auxological and endocrine parameters, bone age, some nutritional indices (hemoglobin, serum iron, calcium, total protein, and albumin), and anti-gliadin antibodies (AGA) IgA and IgG and 1-h blood xylose levels were evaluated in 49 children of short stature. On the basis of the intestinal biopsy, 29 (59.1%) patients affected by CD were found. When patients with atrophic and normal intestinal mucosa were compared, significant differences in the frequency of pathological values of hemoglobinemia, serum iron, AGA, and 1-h blood xylose levels were found, whereas no difference was observed in the levels of serum calcium, total protein, and albumin. Bone age was delayed in 81% of the celiac patients and in 47% of the controls. In particular, AGAs were found in 27 of 29 celiac patients and in three control subjects who showed a low level of one of the two antibodies. The results of our study demonstrate that AGA (IgA and IgG), together with 1-h blood xylose, hemoglobinemia, serum iron, and family history of CD determination, are extremely useful for screening patients of short stature. This type of screening cannot, however, replace the intestinal biopsy because such tests cannot be completely sensitive and specific.