Antibodies in relation to gluten intake

Serum reticulin, endomysial and gliadin antibody tests are used in serological screening and case finding of coeliac disease, as well as the novel tissue transglutaminase antibody test. None of these tests are 100% predictive, however. Reticulin/endomysial antibodies predict forthcoming coeliac disease in individuals with normal small-bowel mucosal morphology. The effect of a gluten-free diet can be monitored with serological tests. A positive test result often indicates an inadequate gluten-free diet. However, slight dietary transgressions and minor mucosal damages cannot always be revealed with the serological tests. Therefore, small-bowel mucosal biopsy remains the most sensitive method to monitor the effect of a gluten-free diet.     

IgA-class transglutaminase antibodies in evaluating the efficacy of gluten-free diet in coeliac disease

OBJECTIVE : Serum IgA-class tissue transglutaminase antibody has proved effective in screening for coeliac disease. The response to a gluten-free diet has been assessed on the basis of small-intestinal morphology. We investigated whether the tissue transglutaminase antibody test could substitute biopsy in this respect, and whether the test is better than the endomysial antibody test in follow-up. DESIGN : Controlled cross sectional, and follow-up study. METHODS : Serum IgA-class tissue transglutaminase antibodies and endomysial antibodies were determined in 87 coeliac adults on a gluten-free diet. All underwent small bowel biopsy, and the mucosal morphology was interpreted along with Marsh's grading 0-3. In 30 patients histological and serological data could be analysed before and after adopting the diet; Marsh 3 was considered inadequate mucosal recovery during the diet. RESULTS : Of the 87 coeliac patients 27 showed Marsh 3 villous atrophy on gluten-free diet; of these 27, tissue transglutaminase antibody was within normal limits in 16 (59%) and endomysial antibody in 20 (74%). Two (7%) out of 29 with normal mucosa (Marsh 0) had positive tissue transglutaminase antibodies. Six (55%) out of 11 admitting regular dietary lapses remained tissue transglutaminase antibody negative. In the follow-up, serum IgA-class tissue transglutaminase antibody was initially positive in 28 (93%) out of 30 untreated patients; even a significant decrease in tissue transglutaminase antibody did not guarantee mucosal recovery. CONCLUSIONS : A substantial number of coeliac patients with negative tissue transglutaminase or endomysial antibodies may still have manifest mucosal villous atrophy. Small bowel biopsy is therefore still necessary to ensure that the gluten-free diet is adequate.     

Coeliac disease among healthy members of multiple case coeliac disease families

BACKGROUND: The main objective of the study was to assess the frequency of undetected coeliac disease among the first-degree relatives of families with two or more previously diagnosed coeliac disease patients. The value of the serum endomysial antibody test as a single means of detecting clinically silent coeliac disease was evaluated. The correlation of endomysial and tissue transglutaminase antibodies and the correlation of endomysial antibodies to the HLA typical for coeliac disease was determined. METHODS: A total of 137 multiple-case coeliac disease families with 872 family members were recruited; 466 healthy family members were simultaneously screened for gliadin and endomysial antibodies and thereafter for tissue tranglutaminase antibodies. Antibody-positive persons were typed for HLA-DQ2 and DQ8. The diagnosis of coeliac disease was based on the typical mucosal lesion on small-bowel biopsies. RESULTS: Forty-four (9.4%) of the healthy family members were positive for endomysial and 48 (10.3%) for gliadin antibodies; 42 biopsies revealed 29 new coeliac disease patients (6.2% of healthy individuals). Endomysial antibodies detected 97% and gliadin antibodies 52% of the new cases. All 44 endomysial-antibody-positive and 35 of 48 gliadin-antibody-positive individuals were positive for DQ2. Tissue transglutaminase antibodies corresponded well with endomysial antibodies. CONCLUSIONS: Undetected coeliac disease is common even among healthy first-degree relatives of multiple case families. The findings emphasize the value of serum endomysial antibodies in the detection of clinically silent coeliac disease. Endomysial-antibody-positive individuals, unlike gliadin-antibody-positive ones, share the coeliac disease-type HLA-DQ.     

Usefulness of Antibodies to Deamidated Gliadin Peptides in Celiac Disease Diagnosis and Follow-up

The prevalence of the recently described deamidated gliadin peptide antibodies was compared with that of the routinely used antigliadin, antiendomysial, and tissue transglutaminase antibodies in the sera of 128 untreated celiac patients and 134 controls. Sensitivity and specificity for celiac disease were 83.6 and 90.3% for IgA and 84.4 and 98.5% for IgG antibodies to deamidated gliadin peptides. The new test displayed higher diagnostic accuracy than antigliadin antibodies and, although less sensitive than antiendomysial and tissue transglutaminase antibodies, showed significantly higher specificity than tissue transglutaminase antibodies (P < 0.001). Persistence of peptide antibodies after gluten withdrawal was an expression of low compliance with the diet and of the lack of improvement of the intestinal mucosa. The combined use of tissue transglutaminase and deamidated gliadin peptide antibodies seems to be a very useful tool for celiac disease diagnosis. Moreover, antibodies to deamidated gliadin peptides can be helpful in disease follow-up.     

Anti-transglutaminase antibodies and coeliac disease

Background: Anti-endomysial antibodies have high specificity for coeliac disease but measurements are limited by the requirement for monkey oesophagus, a substrate that is expensive, and of limited availability and ethical acceptance. Tissue transglutaminase has recently been identified as the endomysial autoantigen in coeliac disease.
Aims: To examine the validity of serum tissue transglutaminase antibody levels in patients with coeliac disease and to assess their sensitivity and specificity against standard serological tests.
Methods: Serum IgA anti-tissue transglutaminase antibody titres (measured by ELISA), IgA anti-gliadin antibody litres (measured by a commercial ELISA) and anti-endomysial antibody titres (measured by indirect immunofluorescence) were determined in 46 untreated and 14 treated patients biopsy-proven coeliac disease and 145 disease and healthy controls.
Results: All patients with untreated coeliac disease were positive for anti-endomysial and anti-tissue transglutaminase antibodies (sensitivity 100%). Seventy-one per cent of treated coeliac patients were anti-tissue transglutaminase antibody negative. Five of 145 disease and healthy controls had low titres of anti-tissue transglutaminase antibody (specificity 97%); no controls were anti-endomysial antibody positive.
Conclusions: Our results demonstrated the sensitivity and specificity of IgA anti-tissue transglutaminase antibodies to correlate highly with anti-endomysial antibodies in the diagnosis of coeliac disease. The ELISA for IgA anti-tissue transglutaminase antibodies is quantitative and easy to perform and is a valid alternative to indirect immunofluorescence for anti-endomysial antibodies in screening for suspected coeliac disease.     

Antibodies to gliadin in adult coeliac disease and dermatitis herpetiformis

Antibodies to gliadin, searched for by indirect immunofluorescence and a micro-ELISA, were detected in 16 (64%) of 25 sera from patients with adult coeliac disease and in 13 (45%) of 29 with dermatitis herpetiformis. Although the sensitivity of the two tests was relatively low in the whole groups, it increased when only cases with severe jejunum abnormalities were considered (93% for coeliac disease and 81% for dermatitis herpetiformis). A significant correlation was found between antigliadin antibodies and the severity of jejunum damage in both diseases. Moreover, most coeliac and dermatitis herpetiformis patients with antigliadin antibodies were on normal diet. The specificity of the tests was 100% for the immunofluorescence and fairly good for the micro-ELISA, as only 5 (11%) of the 46 disease control patients (Crohn's disease, ulcerative colitis) were positive for antigliadin antibodies. R1-reticulin antibody test was equally specific but less sensitive in both groups. We conclude that antigliadin antibodies are useful in the diagnosis of patients with active adult coeliac disease and dermatitis herpetiformis with gluten-sensitive enteropathy. Moreover, the two tests make it possible to monitor the compliance to gluten-free diet in both diseases.     

Performance of a new rapid whole blood coeliac test in adult patients with low prevalence of endomysial antibodies

BACKGROUND: In coeliac disease endomysial and transglutaminase autoantibodies are directed against the human autoantigen, transglutaminase. The conventional coeliac antibody tests are performed from serum samples in centralized laboratories. AIMS: To evaluate a rapid and easy immunoglobulin A-class whole blood point-of-care test and its commercial application, the Biocard test, in coeliac autoantibody detection. METHODS: In the whole blood point-of-care test transglutaminase is liberated from the red blood cells by haemolysis. Transglutaminase antibodies, if present, complex with the liberated antigen, and are visualized. Altogether 51 biopsy-proven untreated coeliac adult patients, 48 of the same patients after treatment, and 36 controls were tested. The point-of-care test results were compared with serum endomysial and transglutaminase antibody and Biocard test results and histology. RESULTS: The whole blood point-of-care test was as sensitive (82%) as the serum endomysium test (80%) in detecting untreated coeliac disease while the serum transglutaminase antibody test was superior (88%). The tests had 100% specificity. A positive point-of-care test result seroconverted or the test reaction weakened in 90% of the treated coeliac patients. Biocard test-positive were 22 of the 24 tested untreated coeliac patients. Biocard test-negative were 15 of 19 controls. CONCLUSIONS: The whole blood rapid tests are as reliable as the conventional serological tests in detecting untreated coeliac disease and in coeliac disease diet monitoring.     

Diagnostic accuracy of coeliac serological tests: a prospective study

OBJECTIVE: The best way to test serologically for coeliac disease (CD) remains controversial, with endomysial (EMA), transglutaminase (TTG), and gliadin antibodies (AGA) being assessed in various combinations with no apparent standardization. The objective of this study was to evaluate whether TTG-IgA+/-TTG-IgG could be used as a replacement for endomysial antibodies as a reliable screen for CD in patients presenting to a major Australian tertiary referral hospital for assessment of symptoms consistent with CD. METHODS: Individuals referred for gastroscopic assessment of possible CD were prospectively evaluated by duodenal biopsy assessment. The following diagnostic methods were compared: dual-isotype transglutaminase (TTG-dual), combined-isotype transglutaminase (TTG-IgA+G), TTG-IgA, combined-isotype gliadin antibodies (AGA-IgA+G), AGA-IgA, and endomysial antibody assays. Clinical performance characteristics (sensitivity, specificity, area under the curve for receiver-operating characteristic analysis; AUROC) were assessed for all kits. RESULTS: The correlation between transglutaminase kits was generally good, with the best transglutaminase kit demonstrating high correlation (r=0.86) with endomysial antibodies. A comparison of different types of endomysial antibody assays displayed variable diagnostic performance (sensitivity 61.90-68.42%; specificity 80.00-98.57%; AUROC 0.71-0.83). Sensitivity (90.48-92.31%), specificity (80.77-82.89%) and AUROC values (0.92-0.94) for dual-isotype transglutaminase kits displayed narrow ranges. AGA assays were less sensitive (AGA-IgA: 42.31-46.15%; AGA-IgG: 61.54%) and less specific (AGA-IgA: 85.09-87.73%; AGA-IgG: 82.46-84.09%). Dual-isotype transglutaminase testing was diagnostically equivalent to transglutaminase-IgA (AUROC 0.92 versus 0.91, P=0.33). CONCLUSIONS: Our study suggests that transglutaminase screening (using the IgA+/-IgG isotype) is a sensitive and specific alternative to endomysial antibody testing in the serological assessment of CD. On the basis of our findings, AGA antibody testing no longer appears to be an essential part of the diagnostic strategy for adult CD.     

Small-bowel mucosal transglutaminase 2-specific IgA deposits in coeliac disease without villous atrophy: a prospective and randomized clinical study

OBJECTIVE: In coeliac disease, autoantibodies directed against transglutaminase 2 are produced in small-bowel mucosa, and they have been found to be deposited extracellularly. The aim of this study was to investigate whether such mucosal IgA deposits are important in the diagnostic work-up of early-stage coeliac disease without small-bowel mucosal villous atrophy. MATERIAL AND METHODS: Forty-one adults suspected of coeliac disease owing to increased density of mucosal gamma(delta)+ intraepithelial lymphocytes but normal villous morphology were randomized to gluten challenge or a gluten-free diet for 6 months. Clinically and histologically verified gluten dependency was compared with existence of small-bowel mucosal transglutaminase 2-specific extracellular IgA deposits and (coeliac disease-type) HLA DQ2 and DQ8; 34 non-coeliac subjects and 18 patients with classical coeliac disease served as controls. RESULTS: Of the 41 patients, 5 in the challenge group and 6 in the gluten-free diet group were clinically gluten sensitive; all 11 had HLA DQ2 or DQ8. Ten of these 11 patients showed transglutaminase 2-targeted mucosal IgA deposits, which were dependent on gluten consumption. Minimal IgA deposits were seen in only 3 out of 30 patients with suspected coeliac disease without any clinically detected gluten dependency. The deposits were found in all classical coeliac patients and in none of the non-coeliac control subjects. CONCLUSIONS: Clinically pertinent coeliac disease exists despite normal small-bowel mucosal villous architecture. Mucosal transglutaminase 2-specific IgA deposits can be utilized in detecting such patients with genetic gluten intolerance.     

Atypical coeliac disease found with serologic screening

Eighteen patients with coeliac disease were found by screening for reticulin antibodies of unselected sera at the time when determination of various tissue antibodies was requested. Joint disease, allergic and pulmonary disorders, and diabetes were particularly observed. IgA class reticulin antibody, in particular, proved to be specific for coeliac disease. Most patients with coeliac disease also had positive serum gliadin antibodies. Abdominal symptoms and signs of malabsorption were slight and infrequent. In most patients a gluten-free diet resulted in the improvement of jejunal mucosal histology, and serum reticulum and gliadin antibody titres decreased simultaneously, reflecting the appropriateness of the diet. Coeliac disease often has mild and atypical symptoms, and, particularly in certain disease groups, screening with reticulin antibody test seems to be appropriate.     

Atypical Coeliac Disease Found with Serologic Screening

Eighteen patients with coeliac disease were found by screening for reticulin antibodies of unselected sera at the time when determination of various tissue antibodies was requested. Joint disease, allergic and pulmonary disorders, and diabetes were particularly observed. IgA class reticulin antibody, in particular, proved to be specific for coeliac disease. Most patients with coeliac disease also had positive serum gliadin antibodies. Abdominal symptoms and signs of malabsorption were slight and infrequent. In most patients a gluten-free diet resulted in the improvement of jenunal mucosal histology, and serum reticulum and gliadin antibody titres decreased simultaneously, reflecting the appropriateness of the diet. Coeliac disease often has mild and atypical symptoms, and, particularly in certain disease groups, screening with reticulin antibody test seems to be appropriate.     

Diagnosis of coeliac disease

The diagnosis of coeliac disease depends on the finding of characteristic, though not specific changes, of intraepithelial lymphocytosis, crypt hyperplasia and various degrees of villous height reduction identified in duodenal biopsies of individuals ingesting a gluten containing diet, together with symptomatic and histologic improvement on gluten withdrawal. Serologic testing has become the main mode of determining who will undergo biopsy. The IgA endomysial antibody and IgA tissue transglutaminase antibody have approximately 90% sensitivity and specificity, though there are reports of lower sensitivity and specificity in the clinical practice setting. This is due to lower titers of these antibodies in the presence of lesser degrees of mucosal damage. The widespread availability of serologic tests for coeliac disease allows the diagnosis to be considered by any physician. Gastroenterologists will be required to interpret the results of serologic tests and perform duodenal biopsies when indicated. Pathologists likewise need to be better acquainted with the more subtle changes of cell mediated immunity within the mucosa that are suggestive of underlying gluten sensitivity.     

Screening for coeliac disease in adults by simultaneous determination of IgA and IgG gliadin antibodies

On a gluten-containing diet, patients with untreated coeliac disease have circulating IgA and/or IgG antibodies against the gliadin fraction of gluten. In the present study sera from 69 adults with coeliac disease, 93 adults with other gastrointestinal diseases, and 112 blood donors were tested for IgA and IgG gliadin antibodies by means of DIG-ELISA, a solid-phase immunosorbent assay. A predictive value of a positive test of 95% and a diagnostic specificity of 98% indicate that screening for gliadin antibodies can be highly recommended in suspected adult coeliac disease. It may further be used as a diagnostic test when small-bowel biopsy specimens are difficult to obtain. The results also indicate that the method is valuable for monitoring dietary treatment in outpatient control of coeliac patients.     

Altered small-bowel mucosal vascular network in untreated coeliac disease

Objective. It has recently been shown that serum autoantibodies targeted against transglutaminase 2 derived from untreated coeliac patients can disturb several steps of angiogenesis in vitro. The purpose of this study was to establish whether the small-bowel mucosal vasculature is altered in coeliac disease and whether the putative changes are gluten dependent. Material and methods. The small-bowel mucosal microvessel architecture was examined in duodenal biopsy samples from coeliac patients before and after a gluten-free diet and from non-coeliac controls. In addition, the vasculature was subjected to a detailed morphometric analysis. Double immunofluorescent stainings of the vasculature with anti- α-smooth muscle actin antibody were performed in order to assess the maturity of mucosal vessels. Coeliac disease-specific transglutaminase 2-targeted autoantibody deposits in the vessel wall were studied using triple immunofluorescent stainings. Results. On a gluten-containing diet the mucosal vasculature in the small intestine of untreated coeliac disease patients was altered in overall organization as well as in the number and maturity of the vessels when compared to healthy subjects. In patients on a gluten-free diet, the vasculature normalized parallel to mucosal recovery. Conclusions. In coeliac disease, ingestion of gluten leads to altered appearance of small-bowel mucosal microvasculature. It is thus conceivable that the small-bowel mucosal vascular biology might be involved in the pathogenesis of coeliac disease.     

Association of coeliac disease with primary biliary cirrhosis in Poland

OBJECTIVES: In western and northern but not southern Europe, the prevalence of coeliac disease among patients with primary biliary cirrhosis (PBC) is higher than in the general population. We analysed the prevalence of coeliac disease among patients with PBC in Poland, a central European country. METHODS: In 115 patients with PBC, immunoglobulin A (IgA) antibodies against guinea-pig tissue transglutaminase (tTGA), monkey endomysium (EMA) and gliadin (AGA) were determined. In patients positive for tTGA and/or EMA, the DNA typing of HLA-DQB gene and small-bowel biopsy were performed. RESULTS: IgA EMA was found in one patient with PBC (0.9%, 95% CI 0-2.5%). tTGA was detected in seven patients (6%, 95% CI 1.8-10.3%). Small-bowel biopsy showed flat mucosa in one subject, who was EMA positive/tTGA negative/AGA negative, and normal histology in four tTGA-positive/EMA-negative patients. In the latter four patients, the positive tTGA result was caused by IgA reactivity to proteins other than transglutaminase. Prevalence of coeliac disease in our 115 patients with PBC was 0.9% (95% CI 0-1.9%). In one patient with silent coeliac disease presenting with the HLA-DQ2 allele, introduction of a gluten-free diet was followed by improvement in liver function tests, improvement in histology of the distal duodenum, and disappearance of EMA. CONCLUSIONS: Our results from Poland do not confirm a high prevalence of coeliac disease in PBC patients. Guinea-pig liver transglutaminase immunolinked assay cannot be used as a screening test for coeliac disease in PBC patients. A gluten-free diet may be helpful in restoration of liver function in patients with such an association.     

Intolerance to cereals is not specific for coeliac disease

BACKGROUND: Abdominal complaints after ingestion of cereals are not uncommon. We assessed how reliable such a history is as a marker for the presence of overt coeliac disease, and whether we should also take into account latent coeliac disease and cereal allergy. METHODS: The study group comprised 93 consecutive adults from health centres spontaneously reporting abdominal symptoms after consumption of cereals. Small bowel mucosal morphology, CD3+, alphabeta+ and gammadelta+ intraepithelial lymphocytes (IELs), HLA DQ alleles and serum IgA-class endomysial (EmA), tissue transglutaminase (tTg) and gliadin (AGA) antibodies were determined. Skin prick and patch tests and serum radioallergosorbent tests for cereals were carried out. Thirty non-coeliac adults served as biopsy controls. RESULTS: Eight (9%) patients had coeliac disease and one mild partial villous atrophy. Altogether 17 had an increased density of gamma delta+ IELs without atrophy. However, only seven (8%) showed evidence of latent coeliac disease, i.e. both an increase in gammadelta+ IELs and the presence of coeliac disease-type HLA. One or more of the allergy tests for cereals was positive in 19; 9 adopted a gluten-free diet and abdominal symptoms were alleviated in all. In non-coeliac patients, serum EmA and tTg tests were negative in all, whereas AGA was seen in 40%. CONCLUSIONS: Intolerance to cereals is not a specific sign of overt or latent coeliac disease. All experimental dietary interventions before proper diagnosis of coeliac disease are therefore to be discouraged. Allergy to cereals, on the other hand, should be considered even in adults.     

Accuracy of testing for antibodies to synthetic gliadin-related peptides in celiac disease.

BACKGROUND & AIMS: Our aim was to explore the diagnostic value of a newly developed synthetic peptide antibody assay addressing specific synthetic gliadin-derived deamidated peptides (AGA II) for the diagnosis of celiac disease (CD). METHODS: We assayed serum samples obtained prospectively at diagnosis from a population of 92 consecutive adult patients with CD and 113 non-CD controls. Patients were reevaluated after 6 months (n = 56) and 1 year (n = 20) of treatment. All patients and controls underwent intestinal biopsy and a set of CD-related serology tests. A newly developed enzyme-linked immunosorbent assay (ELISA) for detecting IgA and IgG antibodies against synthetic deamidated gliadin epitopes was used. RESULTS: At diagnosis, sensitivity and specificity were 94.6% and 99.1% for AGA II IgA and 92.4% and 100% for AGA II IgG. Absolute values and the proportion of positive samples for both antibodies were significantly reduced at 6 months (P < .0000) and 1 year (P < .001) after initiation of a gluten-free diet. Compared with conventional AGA, the peptide antibodies had greater sensitivity, specificity, positive and negative predictive values, accuracy, and likelihood ratios. Compared with antitissue transglutaminase antibodies, AGA II had similar sensitivity but greater specificity and predictive values, better likelihood ratios, and an excellent agreement (kappa statistic = .92). CONCLUSIONS: This study assessed the value of an ELISA assay in detecting antibodies to gliadin-related peptides. This assay appears to be a reliable tool for diagnosing CD and suggests promising accuracy that may be very useful in clinical practice.     

Small-bowel mucosal transglutaminase 2-specific IgA deposits in coeliac disease without villous atrophy: A prospective and randomized clinical study

Objective In coeliac disease, autoantibodies directed against transglutaminase 2 are produced in small-bowel mucosa, and they have been found to be deposited extracellularly. The aim of this study was to investigate whether such mucosal IgA deposits are important in the diagnostic work-up of early-stage coeliac disease without small-bowel mucosal villous atrophy.

Material and methods Forty-one adults suspected of coeliac disease owing to increased density of mucosal γδ+ intraepithelial lymphocytes but normal villous morphology were randomized to gluten challenge or a gluten-free diet for 6 months. Clinically and histologically verified gluten dependency was compared with existence of small-bowel mucosal transglutaminase 2-specific extracellular IgA deposits and (coeliac disease-type) HLA DQ2 and DQ8; 34 non-coeliac subjects and 18 patients with classical coeliac disease served as controls.

Results Of the 41 patients, 5 in the challenge group and 6 in the gluten-free diet group were clinically gluten sensitive; all 11 had HLA DQ2 or DQ8. Ten of these 11 patients showed transglutaminase 2-targeted mucosal IgA deposits, which were dependent on gluten consumption. Minimal IgA deposits were seen in only 3 out of 30 patients with suspected coeliac disease without any clinically detected gluten dependency. The deposits were found in all classical coeliac patients and in none of the non-coeliac control subjects.

Conclusions Clinically pertinent coeliac disease exists despite normal small-bowel mucosal villous architecture. Mucosal transglutaminase 2-specific IgA deposits can be utilized in detecting such patients with genetic gluten intolerance.     

Wheat starch-containing gluten-free flour products in the treatment of coeliac disease and dermatitis herpetiformis. A long-term follow-up study

BACKGROUND: We investigated whether wheat starch-based gluten-free products are safe in the treatment of gluten intolerance. METHODS: The study involved 41 children and adults with coeliac disease and 11 adults with dermatitis herpetiformis adhering to a gluten-free diet for 8 years on average. Thirty-five newly diagnosed coeliac patients at diagnosis and 6 to 24 months after the start of a gluten-free diet and 27 non-coeliac patients with dyspepsia were investigated for comparison. Daily dietary gluten and wheat starch intake were calculated. Small-bowel mucosal villous architecture, CD3+, alphabeta+, and gammadelta+ intraepithelial lymphocytes, mucosal HLA-DR expression, and serum endomysial, reticulin, and gliadin antibodies were investigated. RESULTS: Forty of 52 long-term-treated patients adhered to a strict wheat starch-based diet and 6 to a strict naturally gluten-free diet; 6 patients had dietary lapses. In the 46 patients on a strict diet the villous architecture, enterocyte height, and density of alphabeta+ intraepithelial lymphocytes were similar to those in non-coeliac subjects and better than in short-term-treated coeliac patients. The density of gammadelta(+)cells was higher, but they seemed to decrease over time with the gluten-free diet. Wheat starch-based gluten-free flour products did not cause aberrant upregulation of mucosal HLA-DR. The mucosal integrity was not dependent on the daily intake of wheat starch in all patients on a strict diet, whereas two of the six patients with dietary lapses had villous atrophy and positive serology. CONCLUSION: Wheat starch-based gluten-free flour products were not harmful in the treatment of coeliac disease and dermatitis herpetiformis.     

An immunodominant DQ8 restricted gliadin peptide activates small intestinal immune response in in vitro cultured mucosa from HLA-DQ8 positive but not HLA-DQ8 negative coeliac patients

BACKGROUND: Studies on intestinal T cell clones from the mucosa of patients with coeliac disease have led to the identification of immunogenic gliadin epitopes. One is HLA-DQ8 restricted, its recognition by T cells being increased by introduction of negatively charged residues operated by tissue transglutaminase. AIM: To test HLA-DQ8 restricted epitope in both native (QYPSGQGSFQPSQQNPQA) and deamidated (QYPSGEGSFQPSQENPQA) forms in an organ culture system of treated coeliac mucosa from HLA-DQ8 positive and HLA-DQ8 negative patients. PATIENTS AND METHODS: Jejunal biopsies obtained from 10 patients with coeliac disease (six HLA-DQ8 positive and four HLA-DQ8 negative) were cultured in vitro with a peptic-tryptic digest (PT) of gliadin, or with the native (peptide A) or deamidated (peptide B) peptide. Intraepithelial CD3(+) and lamina propria total CD25(+) and CD3(+)CD25(+) cells were counted, lamina propria intercellular adhesion molecule 1 (ICAM-1) expression was evaluated, as well as that of Fas molecules on epithelial cells. RESULTS: In HLA-DQ8 positive, but not in HLA-DQ8 negative, coeliacs the density of intraepithelial CD3(+) cells, lamina propria total CD25(+), and CD3(+)CD25(+) cells, as well as expression of ICAM-1 and Fas molecules were significantly increased in biopsies cultured with PT, peptide A, or peptide B compared with biopsies cultured in medium alone. CONCLUSION: These data show that the DQ8 restricted gliadin peptide is immunogenic only in the intestinal mucosa of HLA-DQ8 positive coeliac patients in both native and deamidated forms.