Antiendomysium versus Antigliadin Antibodies in Screening the General Population for Coeliac Disease

Background: It has recently been shown that mass screening for coeliac disease, using either the serum antigliadin (AGA) or antiendomysium antibodies (EMA) as screening test, can detect large numbers of cases that had escaped clinical diagnosis. The influence of the diagnostic algorithm on the results of the coeliac screening has not yet been evaluated. Our aim was to compare the validity of the AGA and the EMA protocols in 2096 students living in northwest Sardinia, who took part in a serologic screening for coeliac disease. Methods: The sample included 2096 of 2345 eligible students (89%) aged 11-15 years who underwent serum IgG AGA, IgA AGA, and IgA EMA determinations. Total serum IgA level was measured in sera showing isolated IgG AGA positivity. Subjects showing at least one of the following: a) EMA positivity, b) IgA AGA positivity, or c) IgG AGA positivity and IgA deficiency (<5 mg/dl) were asked to submit to a small-intestinal biopsy. Results: The prevalence of coeliac disease was 19 (16 showing typical enteropathy, 1 potential case, and 2 known cases) of 2096 (0.91%; 95% confidence interval = 0.50-1.31). Seventeen small-intestinal biopsy specimens were needed to confirm 16 cases of manifest coeliac disease (positive predictive value (PPV) = 94%) by the EMA protocol, whereas the AGA protocol required 21 biopsy specimens for 12 cases of coeliac disease (PPV = 57%). None of six IgA-deficient, IgG AGA-positive cases detected by the AGA protocol also had coeliac disease. Conclusions: The EMA protocol is superior to the AGA protocol for mass screening of coeliac disease because of higher sensitivity, decreased need for intestinal biopsy, and possibility to detect potential cases of coeliac disease.     

Antiendomysium versus antigliadin antibodies in screening the general population for coeliac disease

BACKGROUND: It has recently been shown that mass screening for coeliac disease, using either the serum antigliadin (AGA) or antiendomysium antibodies (EMA) as screening test, can detect large numbers of cases that had escaped clinical diagnosis. The influence of the diagnostic algorithm on the results of the coeliac screening has not yet been evaluated. Our aim was to compare the validity of the AGA and the EMA protocols in 2096 students living in northwest Sardinia, who took part in a serologic screening for coeliac disease. METHODS: The sample included 2096 of 2345 eligible students (89%) aged 11-15 years who underwent serum IgG AGA, IgA AGA, and IgA EMA determinations. Total serum IgA level was measured in sera showing isolated IgG AGA positivity. Subjects showing at least one of the following: a) EMA positivity, b) IgA AGA positivity, or c) IgG AGA positivity and IgA deficiency (<5 mg/dl) were asked to submit to a small-intestinal biopsy. RESULTS: The prevalence of coeliac disease was 19 (16 showing typical enteropathy, 1 potential case, and 2 known cases) of 2096 (0.91%; 95% confidence interval = 0.50-1.31). Seventeen small-intestinal biopsy specimens were needed to confirm 16 cases of manifest coeliac disease (positive predictive value (PPV) = 94%) by the EMA protocol, whereas the AGA protocol required 21 biopsy specimens for 12 cases of coeliac disease (PPV = 57%). None of six IgA-deficient, IgG AGA-positive cases detected by the AGA protocol also had coeliac disease. CONCLUSIONS: The EMA protocol is superior to the AGA protocol for mass screening of coeliac disease because of higher sensitivity, decreased need for intestinal biopsy, and possibility to detect potential cases of coeliac disease.     

Screening for adult coeliac disease – which serological marker(s) to use?

OBJECTIVE: To determine which serological marker(s) to use when screening for coeliac disease. DESIGN: In a population-based cross-sectional study we compared the use of antigliadin antibodies (AGA) of isotypes IgA and IgG, antiendomysial antibodies (AEA) of isotype IgA and antitransglutaminase antibodies (ATGA) of isotype IgA for detecting coeliac disease amongst adults. SETTING: Northern Sweden. SUBJECTS: A total of 1850 of 2500 (74%) invited adults (aged 25-74 years) who were randomly selected from the population register after stratification for age and sex. MAIN OUTCOME MEASURES: The sensitivity, specificity and predictive values of the AGA, ATGA and AEA tests. RESULTS: Nine cases of biopsy proven, previously undiagnosed coeliac disease were detected by screening. The sensitivity of both ATGA and AEA was 100% whilst AGA IgA and IgG both had a sensitivity of 89%. The AEA test had a specificity of 100% whereas the specificities of the ATGA, AGA IgA and IgG tests were 97, 96 and 78%, respectively. The positive predictive value for the AEA test was 100%, whereas it was considerably lower for the other tests (ATGA > AGA IgA > AGA IgG), with further decreases for all tests when shifting from a clinical to a screening situation. CONCLUSIONS: When screening for coeliac disease we suggest a serial testing approach, i.e. an initial ATGA test and, when positive, followed by an AEA test, provided that IgA deficiency has been excluded. However, assessment of the small intestinal mucosal morphology is still required to ascertain the diagnosis.     

Human recombinant anti-transglutaminase antibody testing is useful in the diagnosis of silent coeliac disease in a selected group of at-risk patients

BACKGROUND: Functional dyspepsia, unexplained chronic hypertransaminasaemia (CHT) and hepatitis C virus (HCV) are common gastrointestinal situations that have been related to coeliac disease. Antibodies to tissue transglutaminase (tTG) have been claimed recently to be highly effective as a screening method for coeliac disease. AIM: To assess the prevalence of coeliac disease by means of detection of antibodies against human tTG in the above-mentioned groups of patients. PATIENTS AND METHODS: A control group consisted of 165 normal blood donors. Patient groups comprised 90 CHT patients, 102 HCV patients and 92 functional dyspepsia patients. All patients were tested for anti-tTG (immunoglobulin A, IgA) antibodies. Anti-endomysium (IgA) antibodies (AEA) and antigliadin (IgA) antibodies (AGA) and antigliadin (immunoglobulin G, IgG) antibodies (AGG) were also tested. When anti-tTG or AEA was positive, a duodenal biopsy was recommended. RESULTS: One of 165 blood donors, three of 92 functional dyspepsia patients, four of 90 CHT patients and none of 102 HCV patients were positive for anti-tTG antibodies. In the anti-tTG-positive group, all but one were AEA-positive. There were no AEA- or AGA IgA-positives that revealed a negative anti-tTG test. Duodenal biopsy confirmed a diagnosis of coeliac disease in all the cases. Statistically significant differences were found between the controls and the functional dyspepsia group and between the controls and the CHT group, but not between the controls and the HCV group. CONCLUSIONS: Both CHT and functional dyspepsia may represent a true oligosymptomatic form of coeliac disease. In such conditions, the detection of anti-tTG antibodies is useful as a screening method. Coeliac disease is not an autoimmune manifestation of HCV, so screening for coeliac disease in HCV patients cannot be recommended.     

Coeliac disease in Iraqi type 1 diabetic patients

Background and study aimsHigh prevalence rates of coeliac disease (CD) in patients with type 1 diabetes mellitus (T1DM) have been reported. The aim of this study was to evaluate the frequency of silent CD in a sample of Iraqi patients with T1DM.Patients and methodsThis is a cross-sectional study done in Baghdad Teaching Hospital, Baghdad Medical City, Baghdad, Iraq, on 62 patients with T1DM. For all patients, immunoglobulin A (IgA) anti-tissue transglutaminase antibodies (IgA tTG), IgG anti-tissue transglutaminase antibodies (IgG tTG), IgA endomysial antibody (IgA EMA), IgA antigliadin antibodies (IgA AGA) and IgG antigliadin antibodies (IgG AGA) tests were done, with duodenoscopy, and at least four biopsies were taken from the second part of the duodenum.ResultsA total of 27 patients (43.5%) had normal small-intestinal histopathology (Marsh 0), one of them had a positive result for all serological markers used in the study, and another patient was positive for IgA tTG only. Ten patients (16.1%) had Marsh grade I, one of them was positive for IgA tTG, IgG tTG and IgA EMA, another patient was IgA deficient and had positive IgG tTG only and another patient with Marsh I had positive IgA tTG and IgG tTG only. Two patients (3.2%) had Marsh IIIA; three patients (4.8%) had Marsh IIIB histopathology, two of them were positive for all tests and one had positive IgA tTG and IgA EMA only. Two patients (3.2%) had Marsh IIIC histopathological features; they were positive for all serological tests, hence, the frequency of CD was 11.2%.ConclusionThe frequency of silent CD in Iraqi patients with T1DM is not rare, reaching up to 11.2%. Both EMA and tTG antibodies are useful as screening tests.     

Should relatives of coeliacs with mild clinical complaints undergo a small-bowel biopsy despite negative serology?

BACKGROUND AND OBJECTIVES: Small intestinal lesions in coeliac disease (CD) have a variable severity. Early diagnosis of CD is important because treatment allows a normal psycho-physical development, especially in children, and can avoid associated disorders. The aim of this study was to evaluate the predictive value of screening parameters for the detection and estimation of CD prevalence in first-degree relatives. METHODS: The screening was performed in 338 first-degree relatives of 134 coeliac families. Questionnaires and a physical examination followed by haematological analyses and serologyfor IgA anti-endomysium (EMA)/IgA antigliadin (AGA) antibodies were used in orderto selectthe candidates for small-bowel biopsy. The small-bowel biopsy was indicated on the basis of clinical complaints, laboratory tests and serology performed in 96 (28%) of the study group. RESULTS: CD was diagnosed in 17/96 cases. Six of the 17 showed total villous atrophy (VA) (Marsh IIIc), five subtotal VA (Marsh IIIb) and six partial VA (Marsh IIIa). EMA and AGA were strongly positive in the six patients whose intestinal biopsy showed total VA. However, only one coeliac out of the six patients with partial VA had positive EMA and AGA. CONCLUSION: A significant proportion of coeliacs may be missed if cases are screened by serology only. Although endomysial antibody assay has been reported as a highly sensitive and specific test for detection of CD, we argue that using only EMA and AGA in screening is not enough for investigation of the true prevalence of CD. A combination of clinical parameters as described in this study and laboratory/serological tests is an important and practical contribution to improving the detection rate of CD.     

IgA antigliadin antibodies and persistence of jejunal lesions in adult coeliac disease

In 46 adult patients with coeliac disease, 41 (89%) of whom were positive for IgA and/or IgG antigliadin antibodies (AGA) when untreated, we investigated after a gluten-free diet the relationship between the persistence of AGA, the persistence of jejunal lesions, and the duration and compliance with the diet. IgG AGA were positive in 21 coeliac patients (46%) after variable periods of gluten-free diet and were associated with IgA positivity only in 4 cases (9%). Both IgA and IgG AGA positivity appeared to be more related to the lack of improvement of the jejunal lesions than to the strictness and duration of gluten withdrawal. Nine coeliacs showed no improvement of jejunal lesions after the gluten-free diet. Of these 9, 4 showed persistent IgA AGA, while the remaining 5 resulted IgAAGA-negative as before when untreated. Though intestinal biopsy remains the best means of determining the positive effect of gluten withdrawal, the persistence of IgA AGA in treated coeliacs is always predictive of the persistence of severe jejunal lesions. The persistence of IgG AGA, on the contrary, should be regarded as an immunological memory.     

High prevalence of undiagnosed coeliac disease in adults: a Swedish population-based study

OBJECTIVE: To determine the prevalence of coeliac disease in a population-based sample of Swedish adults. DESIGN: Population-based cross-sectional study. SETTING: Northern Sweden. SUBJECTS: A total of 1894 adults (76%) out of 2500 invited, randomly selected from the population register after stratification for age and sex. MAIN OUTCOME MEASURES: Prevalence of biopsy verified coeliac disease, symptoms of undiagnosed cases, and results of antiendomysium and antigliadin serum antibody tests. RESULTS: Coeliac disease was confirmed by intestinal biopsy showing enteropathy in 10 individuals (seven women and three men), corresponding to a prevalence of 5.3 per 1000 (95% CI = 2.5-9.7). The majority of cases (eight out of 10) had not been diagnosed prior to the screening, although many had symptoms compatible with coeliac disease. All individuals with antiendomysium antibody positivity who were subjected to a small intestinal biopsy had enteropathy. Furthermore, all of them also had elevated levels of antigliadin antibodies type IgA and/or IgG. CONCLUSIONS: Coeliac disease is common, albeit mostly undiagnosed, in Swedish adults. It is likely that the situation is no better in other countries. This highlights the importance of keeping coeliac disease in mind, and of promptly investigating individuals with unexplained, even mild, symptoms compatible with the disease. Serological markers, e.g. antigliadin and antiendomysium antibodies, are useful tools within this active case-finding strategy, although the final diagnosis should be based on an intestinal biopsy demonstrating enteropathy.     

Prevalence of coeliac disease in patients with sarcoidosis

OBJECTIVE: Susceptibility to sarcoidosis and coeliac disease has been linked to the class II haplotype HLA-DR3, DQ2, and an association between the two disorders has been suggested. As a pilot study, we have sought to determine the prevalence of coeliac disease in a cohort of Irish patients with sarcoidosis. DESIGN: Prospective, case-controlled study. METHODS: One hundred and two sarcoid patients (47 males, 55 females) from the west of Ireland and 105 (52 males, 53 females) healthy, ethnically matched, controls underwent interview and screening for coeliac disease and human leucocyte antigen typing by serology. Those with elevated anti-gliadin IgA (AGA) and/or positive endomysial antibody (EMA) were offered small intestinal biopsy. RESULTS: Three (3%) sarcoid patients had a prior diagnosis of coeliac disease. A further 12 (12%) patients and four (4%) controls had elevated AGA (P = 0.047), of whom three and one, respectively, had positive EMA. Small intestinal biopsy in 11 patients and three controls confirmed coeliac disease in one individual each, giving a prevalence of coeliac disease in patients compared with controls of 4/102 (4%) versus 1/105 (1%) (P = 0.21). Sensitivity and specificity of EMA and elevated AGA in sarcoid patients was 100% and 50%, and 50% and 9%, respectively. Of the four affected sarcoid patients, three carried HLA-DR3, DQ2 and one carried DR5 (12), DR7, DQ2. CONCLUSION: We have demonstrated a moderately increased prevalence of coeliac disease in Irish patients with sarcoidosis, which we feel justifies future screening of our sarcoid population. Estimation of EMA is recommended and should be restricted to those with susceptible haplotypes.     

Longitudinal follow-up examination of antigliadin antibody positive children and adults

BACKGROUND: We previously investigated the prevalence of asymptomatic celiac disease in 3004 healthy children and 4313 adult blood donors by screening for IgA and IgG class antigliadin antibodies (AGA) and IgA class anti-endomysial antibodies (EmA). In none of the 162 exclusive AGA-positive adults and in only one of the 117 exclusive AGA-positive children could celiac disease be diagnosed. We followed up AGA-positive individuals in respect of the significance of the AGA. METHODS: All AGA-positive children and adults were invited for a follow-up clinical examination and laboratory investigations including AGA-IgA, AGA-IgG and EmA. Celiac disease-specific antibodies were also determined in stool samples. RESULTS: Sixty-nine adults and 47 children returned for follow-up. In 26 (37.7%) cases of the 69 adults formerly tested AGA-positive, AGA were still detectable after an average period of 3.7 years. In 21 (44.7%) cases of 47 formerly AGA-positive children, AGA were still detectable after an average period of 4.3 years. None of the 69 adults and 47 children showed seroconversion to EmA. There were no significant abnormalities in the laboratory results or any clinical signs of enteropathy.The appearance of fecal and serum antibodies was compared in 112 subjects but no correlation between fecal and serum antigliadin antibodies was found. CONCLUSIONS: In both studied populations of adults and children, AGA disappeared in more than 50% of the cases. The appearance of AGA has to be interpreted as a non-specific immunomodulation phenomenon, confirming the low specificity of AGA as a serologic marker for celiac disease.     

IgA antibodies to gliadin and coeliac disease in psoriatic arthritis.

OBJECTIVES: To find out whether patients with psoriatic arthritis (PsoA) have an increased prevalence of antibodies to gliadin (AGA) and of coeliac disease. METHODS: One hundred and fourteen PsoA patients with skin disease of 20+/-13 yr and joint disease of 11+/-10 yr duration answered a questionnaire concerning their medical history and underwent clinical examination, including radiology. Serum IgA AGA and IgG AGA, IgA antibodies to endomysium and immunoglobulins, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) concentration were determined. RESULTS: Five of the 114 patients (4.4%) had coeliac disease. After exclusion of these five patients, the mean IgA AGA concentration was significantly higher (P=0.0005) than that in a reference group. None of the patients had IgA antibodies to endomysium. The mean serum IgA concentration was significantly increased and IgM decreased. Patients with a high concentration of IgA AGA had significantly higher ESR and CRP and a longer duration of morning stiffness than those with a low AGA concentration. CONCLUSIONS: Patients with PsoA have an increased prevalence of raised serum IgA AGA and of coeliac disease. Patients with raised IgA AGA seem to have more pronounced inflammation than those with a low IgA AGA concentration.     

A primary care cross-sectional study of undiagnosed adult coeliac disease

OBJECTIVES: To establish the prevalence of coeliac disease in the general population and in specific conditions, such as irritable bowel syndrome, iron deficiency anaemia, fatigue and other coeliac-related conditions. METHODS: Primary-care-based cross-sectional study using immunoglobulins, IgA/IgG antigliadin antibodies and endomysial antibodies to initially recognize coeliac disease. A total of 1200 volunteers were recruited from January 1999 to June 2001 from five general practices in South Yorkshire, UK. Any participant with a positive IgA antigliadin antibody, positive endomysial antibody, or only IgG antigliadin antibody in the presence of IgA deficiency was offered a small-bowel biopsy to confirm the diagnosis of coeliac disease. RESULTS: Twelve new cases of coeliac disease were diagnosed from 1200 samples. The prevalence of coeliac disease in this primary care population sample is 1% (95% CI 0.4-1.3%). The prevalence of coeliac disease was 3.3% (4/123) in participants with irritable bowel syndrome, 4.7% (3/64) in participants with iron deficiency anaemia, and 3.3% (3/92) in participants with fatigue. CONCLUSIONS: This study describes the prevalence of undiagnosed adult coeliac disease in primary care patients with irritable bowel syndrome, iron deficiency anaemia and fatigue. Underdiagnosis of coeliac disease is common in primary care. A case-finding approach would avoid delays in diagnosis and the associated morbidity or potential complications of coeliac disease. A low threshold for serological screening of patients with coeliac-associated symptoms or conditions would be an optimal strategy.     

Prevalence of Coeliac Disease in the General Population of Northern Spain: Strategies of Serologic Screening

Background: Coeliac disease (CD) is common in Western countries. In Spain, however, no studies exist on its prevalence. The best method for serologic screening is also unknown. Methods. We determined the IgA and IgG antigliadin antibodies (AGA) and IgA antiendomysium antibodies (AEA) in a sample of 1170 randomly selected subjects from a health area in northern Spain. The prevalence of CD was calculated with a two-step serologic screening method (first IgA and IgG AGA and then AEA in those positive for AGA) or with only one step with AEA determination. Diagnosis was confirmed by small-intestinal biopsy. Results: When using a two-step strategy, we found 174 (15%) subjects with AGA. Only one of these was confirmed by means of AEA (prevalence of CD = 0.9/1000). Two subjects were found to be positive when a one-step strategy was used (prevalence of CD = 1.7/1000). This yielded an economic saving of 19% with regard to the use of a two-step strategy. One new case of CD in a seronegative subject was diagnosed during the study (real prevalence of CD = 2.6/1000; 95% confidence interval = 0.7-8.2). Conclusions: The prevalence of CD in Northern Spain is 2.6/1000 (1:389). One-step serologic screening (AEA) is both more economical and more sensitive than the two-step procedure (first AGA and then AEA if AGA is positive).     

Prevalence of Coeliac disease in the general population of northern Spain. Strategies of serologic screening

BACKGROUND: Coeliac disease (CD) is common in Western countries. In Spain, however, no studies exist on its prevalence. The best method for serologic screening is also unknown. METHODS: We determined the IgA and IgG antigliadin antibodies (AGA) and IgA antiendomysium antibodies (AEA) in a sample of 1170 randomly selected subjects from a health area in northern Spain. The prevalence of CD was calculated with a two-step serologic screening method (first IgA and IgG AGA and then AEA in those positive for AGA) or with only one step with AEA determination. Diagnosis was confirmed by small-intestinal biopsy. RESULTS: When using a two-step strategy, we found 174 (15%) subjects with AGA. Only one of these was confirmed by means of AEA (prevalence of CD = 0.9/1000). Two subjects were found to be positive when a one-step strategy was used (prevalence of CD = 1.7/1000). This yielded an economic saving of 19% with regard to the use of a two-step strategy. One new case of CD in a seronegative subject was diagnosed during the study (real prevalence of CD = 2.6/1000; 95% confidence interval = 0.7-8.2). CONCLUSIONS: The prevalence of CD in Northern Spain is 2.6/1000 (1:389). One-step serologic screening (AEA) is both more economical and more sensitive than the two-step procedure (first AGA and then AEA if AGA is positive).     

Role of human-tissue transglutaminase IgG and anti-gliadin IgG antibodies in the diagnosis of coeliac disease in patients with selective immunoglobulin A deficiency

Background. Selective IgA deficiency is associated with coeliac disease, and studies have shown an increased prevalence of coeliac disease in these patients ranging from 0.71 to 30.7%, depending on the test used for screening.Aims. To determine the sensitivity of IgG anti-gliadin-antibodies and of IgG human-tissue-transglutaminase for diagnosing coeliac disease and assessing its prevalence in subjects with IgA deficiency.Subjects. We tested serum samples from 126 IgA-deficient children (66 female, median age: 10.8 years).Methods. All samples were analysed to measure IgG anti-gliadin-antibodies and IgG anti-human-tissue-transglutaminase. Patients testing positive to either test underwent intestinal biopsy. Subjects testing positive for IgG anti-human-tissue-transglutaminase underwent genetic testing for the human leucocyte antigen heterodimer.Results. Twenty-seven of 126 subjects tested positive for IgG anti-gliadin-antibodies (five of whom tested positive also for IgG anti-human-tissue-transglutaminase) and 18 (including the aforementioned five) for IgG anti-human-tissue-transglutaminase. Intestinal biopsy was performed in 37 of the 40 patients who tested positive (three subjects refused). Eleven had positive intestinal biopsies all of whom tested positive for IgG anti-human-tissue-transglutaminase, but only five of these tested positive also for IgG anti-gliadin-antibodies. All 22 patients testing positive for anti-gliadin-antibody alone had normal intestinal mucosa. All the patients who tested positive for IgG anti-human-tissue-transglutaminase and underwent genetic screening (15/18) had the coeliac-related human leucocyte antigen. Overall, coeliac disease was diagnosed in 11 of the 126 subjects with IgA deficiency (8.7%).Conclusions. The prevalence of coeliac disease in subjects with total IgA deficiency was 8.7%. Assay of IgG anti-human-tissue-transglutaminase can be recommended for screening coeliac disease in IgA-deficient subjects.     

Antibodies to Dietary Antigens in Coeliac Disease

Antibodies to gliadin (AGA) were found in 77 (94%) of 82 sera from patients with active coeliac disease (untreated and after gluten challenge). Although IgG AGA had a higher nosological sensitivity than IgA AGA (88% versus 67%), their nosological specificity was lower than that of IgA antibodies (87% versus 100%). The sensitivity of antibodies to casein, β-lactoglobulin, and ovalbumin in active coeliac disease varied from 36% to 48% without significant difference between IgG and IgA antibodies. IgG and IgA antibodies to milk and egg proteins showed a specificity similar to that of AGA, although some IgA antibodies other than AGA were found in disease controls (Crohn's disease, ulcerative colitis, post-enteritis syndrome).     

Polymeric IgA antibody to gliadin in the serum of patients with coeliac disease

Secretory component (SC) binding assays which detect polymeric IgA (pIgA) in serum were used to measure serum antigliadin pIgA and total pIgA in patients with coeliac disease. Total IgA antigliadin antibody in serum and intestinal fluid was measured by enzyme linked immunosorbent assay (ELISA). The relationship of pIgA antibody to dietary gluten and the antigliadin IgA antibody in intestinal fluid was examined. Twenty-nine serum samples were assayed, twelve from patients ingesting gluten and seventeen from patients who had excluded gluten from their diet for 6 months. Eight of these were paired samples from 4 adults on and off gluten. In addition, paired samples of both intestinal fluid and serum were obtained from 7 children on and off gluten. Polymeric IgA antibody to gliadin was detected in 11 of 12 subjects on gluten but in only 3 of 17 who had excluded gluten. Three of the four adults from whom paired serum samples were obtained had pIgA antigliadin, but only while on gluten. Three of the seven children in whom intestinal and serum antibody were assayed had pIgA to gliadin, which could not be detected after exclusion of gluten, although their intestinal antibody level remained elevated. There was no change in total pIgA levels with diet although the levels were higher than those seen in normal subjects. We conclude that pIgA antibody to gliadin is frequently found in the serum of coeliac patients ingesting gluten. It disappears with gluten elimination at a time when the IgA antigliadin antibody in intestinal fluid has not altered.     

IgG(1) antiendomysium and IgG antitissue transglutaminase (anti-tTG) antibodies in coeliac patients with selective IgA deficiency. Working Groups on Celiac Disease of SIGEP and Club del Tenue

BACKGROUND: In selective IgA deficiency (IgAD), there is no reliable screening test for coeliac disease (CD). AIM: To evaluate the usefulness of IgG(1) antiendomysium and IgG antitissue transglutaminase tests for CD diagnosis in IgAD. METHODS: IgA and IgG antigliadin antibodies (IgA- and IgG-AGA), IgA and IgG(1) antiendomysium antibodies (IgA- and IgG(1)-EMA), and IgA and IgG antitissue transglutaminase (IgA- and IgG-anti-tTG) were assayed in: (a) 20 untreated IgAD/CD patients; (b) 34 IgAD/CD patients on a strict gluten free diet (GFD); (c) 10 IgAD/CD patients not on a strict GFD; (d) 11 untreated CD patients without IgAD; (e) 10 healthy IgAD patients; and (f) 25 healthy controls. RESULTS: In all untreated IgAD/CD patients, IgG(1)-EMA, IgG-anti-tTG, and IgG-AGA were positive whereas IgA antibodies against these antigens were negative. IgAD/CD patients on a strict GFD did not produce IgG-AGA or IgG(1)-EMA but four of 34 produced IgG anti-tTG. IgAD/CD subjects not on a strict GFD produced IgG-AGA whereas 5/10 and 4/10 were IgG(1)- EMA and IgG-anti-tTG negative, respectively. Untreated CD patients without IgAD were AGA (IgA and IgG), EMA (IgA and IgG(1)), and anti-tTG (IgA and IgG) positive. Healthy controls were AGA and EMA negative whereas two of 10 apparently healthy IgAD subjects and one of 25 healthy negative control were IgG-anti-tTG positive. CONCLUSIONS: Both IgG(1)-EMA and IgG-anti-tTG tests appear to be useful for identification of IgAD/CD patients whereas they are less satisfactory for monitoring dietary compliance in these subjects. In addition, our findings seem to suggest that IgG-EMA autoantibodies produced by coeliac patients are mainly of the IgG(1) subtype.     

Antibodies to dietary antigens in coeliac disease

Antibodies to gliadin (AGA) were found in 77 (94%) of 82 sera from patients with active coeliac disease (untreated and after gluten challenge). Although IgG AGA had a higher nosological sensitivity than IgA AGA (88% versus 67%), their nosological specificity was lower than that of IgA antibodies (87% versus 100%). The sensitivity of antibodies to casein, beta-lactoglobulin, and ovalbumin in active coeliac disease varied from 36% to 48% without significant difference between IgG and IgA antibodies. IgG and IgA antibodies to milk and egg proteins showed a specificity similar to that of AGA, although some IgA antibodies other than AGA were found in disease controls (Crohn's disease, ulcerative colitis, post-enteritis syndrome).     

Prevalence of coeliac disease in the adult population of central Greece

OBJECTIVES: Recent studies from several countries have shown that coeliac disease (CD) is increasingly being diagnosed in adults, as the availability of new, accurate serologic tests has made screening in the general population possible. No data exist regarding the prevalence of CD in Greece. The aim of this study was the implementation of a serologic screening procedure for CD in the adult general population of Thessaly, an area of central Greece, using a novel diagnostic algorithm. METHODS: The study included 2230 participants (1226 women, 1004 men, median age 46 years, range 18-80 years), selected by systematic random sampling, from the adult general population of Thessaly. All the serum samples were tested for total immunoglobulin A (IgA)-serum levels, to exclude IgA deficiency. Samples with total IgA within the normal range were tested for IgA antibodies against native human-tissue transglutaminase (anti-tTG); samples that were anti-tTG positive were tested for IgA antiendomysial antibodies (EmA). Samples from participants with selective IgA deficiency were examined for IgG antigliadin antibodies. Participants who were EmA-positive or antigliadin antibody-positive were referred for intestinal biopsy and human leucocyte antigen (HLA) typing. RESULTS: No participant with selective IgA deficiency was detected. Four individuals tested positive for EmA, all of whom were biopsy-proven coeliacs. Therefore, the CD prevalence in this general population sample is 1 : 558 or 1.8 per 1000 (SE 0.13). The four new patients with abnormal histology (two men, two women) were aged between 18 and 35 years. Two of them were considered to be asymptomatic and two presented with a subclinical course. All four had the heterodimer HLA-DQ2. CONCLUSIONS: This first serological screening study for CD in Greece has demonstrated that CD prevalence in Thessaly is among the lowest reported in Europe.