Prevalence and clinical significance of gliadin antibodies in healthy children and adults

Sex Difference in Celiac Disease in Undiagnosed Populations: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

A higher proportion of female vs male patients receive a diagnosis of celiac disease. Little is known about sex-based differences in the prevalence of celiac disease in undiagnosed populations. We aimed to address this knowledge gap with a systematic review and meta-analysis.

METHODS

We searched MEDLINE, Embase, Cochrane, and Scopus databases through 2017 for studies of screen-detected or undiagnosed celiac disease. Our final analysis included studies that included screening and confirmatory tests (either second serologic analysis or a small intestine biopsy) and provided information on the sex of participants. Studies were excluded if they were performed with specific, high-risk, or referral populations. The primary outcome was the percentage of undetected celiac disease among female and male patients.

RESULTS

We identified 4070 articles and analyzed data from 87. Our meta-analysis comprised data from 291,969 study participants. The pooled prevalence of undetected celiac disease in female participants was 0.589% (95% CI, 0.549%-0.629%) and in male participants was 0.415% (95% CI, 0.343%-0.487%). The risk of undetected celiac disease was higher among female than male participants (relative risk [RR], 1.42; 95% CI, 1.27-1.57; P < .00001). The I² was 5% (low heterogeneity among studies). In subgroup analyses, the RR of celiac disease for girls vs boys was 1.79 (95% CI, 1.44-2.22; P < .00001; I² = 18%), the RR for female vs male blood donors was 1.13 (95% CI, 0.76-1.69; P = .54; I² = 0), and the RR for women vs men with villous atrophy was 1.38 (95% CI, 1.07-1.79; P = .01; I² = 0).

CONCLUSIONS

In a systematic review and meta-analysis, we found a higher risk for celiac disease in women than men in an undiagnosed populations (identified through general population screening). The increased risk for celiac disease among girls and women should be considered for screening, diagnosis, and management strategies.

Clinical management of coeliac disease

OBJECTIVE

To describe the prevalence of Coeliac disease (CD) and its clinical management.

METHODS

Narrative review.

RESULTS

Coeliac disease (CD) is an immune-mediated disorder that primarily affects the gastrointestinal (GI) tract. Recent data suggest a prevalence of about 1% in most Western countries, a figure that likely represents an increase in the prevalence of CD. Risk groups include those who are members of families with individuals who have CD as well as those with Type I diabetes and a variety of autoimmune diseases. Whereas biopsy is the gold standard in diagnosis, serological tests are crucial in determining who should undergo endoscopy and biopsy. HLA testing should be used only to rule out CD. Currently, a gluten-free diet is the only available therapy.

CONCLUSION

In conclusion, CD is one of the most common immune-mediated disorders in the Western world. It should be considered in patients with a number of varying GI and non-GI symptoms, as well as in high-risk groups that include first-degree relatives.

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.

The prevalence of celiac disease in average-risk and at-risk Western European populations: a systematic review

Until recently, celiac disease (CD) was felt to be a rare disease in the United States. The aim of this study was to conduct a systematic review of the prevalence of CD in general Western populations and in populations at high risk for CD. Standard systematic review methodology was used. A literature search was conducted in MEDLINE (1966 to October 2003) and EMBASE (1974 to December 2003) databases. Qualitative and quantitative prevalence estimates were produced after assessing study heterogeneity. The prevalence of CD in general Western populations is close to 1% and is somewhat higher in certain Western European populations. The prevalence of CD in populations at risk for CD is as follows: 3%-6% in type 1 diabetic patients, up to 20% in first-degree relatives, 10%-15% in symptomatic iron-deficiency anemia (IDA), 3%-6% in asymptomatic IDA, and 1%-3% in osteoporosis. The prevalence of CD in patients suspected of having CD varied depending on the reasons for suspecting CD and on whether the study was conducted in a referral center. In general, the prevalence ranged from 5% to 15%, but was up to 50% in symptomatic patients evaluated in a tertiary referral center. CD is a common medical condition. The prevalence is higher still in high-risk groups. Clinicians in a variety of specialties should have a high index of suspicion for the diagnosis of CD and in particular need to pay close attention to the identified high-risk groups.

Endocrine autoantibodies

The autoantibody assays that exist and that are being refined are of increasing importance to a broad spectrum of endocrine disorders. This is particularly true for type IA diabetes, which is one of the best-studied organ-specific autoimmune diseases. Autoantibodies are used as valuable markers in prediction and prevention studies of type IA diabetes. Autoantibodies related to other endocrine organs are also important because multiple related autoimmune endocrine and non-endocrine disorders are increased in frequency in patients and their families with autoimmunity. The availability of highly sensitive and specific autoantibody assays for the various endocrine disorders can allow physicians to better diagnose and promptly treat these conditions.

Type 1A diabetes mellitus-associated autoimmunity

Type 1A diabetes mellitus has become one of the most intensively studied autoimmune disorders, with characterized animal models and extensive prospective studies of the development of anti-islet autoimmunity. It is now possible to predict the development of type 1A diabetes mellitus, beginning with HLA-encoded genetic susceptibility, followed by the development of a series of anti-islet autoantibodies. Prediction primarily is based on the detection of multiple anti-islet autoantibodies reacting with cloned islet antigens. Multiple international workshops fostered the development of specific and sensitive radioassays for autoantibodies reacting with GAD65 (glutamic acid decarboxylase), ICA512 (also termed IA-2, a tyrosine phosphatase-like protein), and insulin. Similar high throughput radioassays have been applied using autoantigens for additional autoimmune disorders including celiac disease and Addison's disease. Relatives of patients with type 1A diabetes mellitus inherit susceptibility to express multiple autoantibodies, and a subset of autoantibody-positive individuals inherit susceptibility to progress to overt disease. This article reviews autoimmune disorders associated with type 1A diabetes mellitus.

Gliadin antibodies in adult insulin-dependent diabetes--autoimmune and immunogenetic correlates

Gliadin antibody (GA) tests used in screening for coeliac disease (CD) frequently yield positive GA results without accompanying CD in cases of diabetes mellitus type 1 (DM-1). To enlighten this phenomenon we screened 848 DM-1 patients for IgA- and IgG-GA. Subsequently, 16 out of 19 high titre GA patients (6 with CD) were compared with 37 low titre DM-1 patients matched for sex, age and disease duration, for autoimmune and immunogenetic markers. Chronic thyroiditis and thyroid peroxidase (TPO) antibody positivity were more frequent in the GA-positive than in the GA-negative sub-group (38 vs. 2.7%, p = 0.003, and 69 vs. 27%, p < 0.00, respectively). The tissue transglutaminase (tTg) IgA titres correlated with CD but not with GA. tTg IgG titres were lower in GA-positive individuals (p = 0.0012). GA-positivity correlated with a higher titre of factor XIII IgA antibodies (p < 0.001). GA-positive DM-I patients were characterised by a distinct immunogenetic profile; the risk of HLA DQB1*02 was lower among GA-positive patients than among GA-negatives (OR 0.4, preventive fraction 0.43). All CD patients were HLA DRB1*03-DQB1* 02-positive, but none of the five patients with normal biopsies. GA-positive patients instead had HLA DRB1*13 in 37.5% as compared to 8.6% in GA-negative (OR 6.4, etiologic fraction 0.32). Thus, the occurrence of positive GA in DM-1 is correlated to TPO antibody positivity, thyroiditis and factor XIII IgA antibodies, but inversely correlated to tTg IgG, and seems to be associated with another HLA haplotype than that previously found to be associated with CD.

Celiac disease in older people

In recent years, there has been increasing recognition that the classical textbook presentation of celiac disease with a malabsorption syndrome and a flat jejunal mucosa is only part of a broad spectrum of clinical and histological features associated with gluten sensitivity. Diagnosis of this treatable condition is often delayed or missed because of a failure to appreciate that celiac disease can present at any age and that symptoms are often subtle and not clearly related to gastrointestinal disease. Nonspecific symptoms and nutritional deficiencies are especially common in older patients and may not always be investigated thoroughly. Use of serological screening tests has improved ease of detection of celiac disease in patients without classical symptoms.

Tryptophan hydroxylase autoantibodies and intestinal disease in autoimmune polyendocrine syndrome type 1

Tryptophan hydroxylase antibodies, associated with gastrointestinal disease in autoimmune polyendocrine syndrome type 1, are specific for this disease and not present in patients with other bowel disorders or healthy controls.

Prevalence of IgA-antiendomysium and IgA-antigliadin autoantibodies at diagnosis of insulin-dependent diabetes mellitus in Swedish children and adolescents

OBJECTIVE

This study was conducted to investigate the prevalence of celiac disease (CD) in children and adolescents at diagnosis of insulin-dependent diabetes mellitus (IDDM) before insulin treatment was started.

MATERIAL AND METHODS

At diagnosis of IDDM, and before treatment was started, 115 children and adolescents were screened for IgA- antiendomysium (EMA) and IgA-antigliadin antibodies (AGA). Those found to be EMA-positive and/or AGA-positive were investigated further with intestinal biopsy.

RESULTS

Of the 115 patients, 2 had known CD at diagnosis of IDDM; of the remainder of patients, 6% (7/113) were found to be EMA-positive and 9% (10/113) were found to have AGA levels above normal. Of the 6 patients who underwent biopsy, 5 manifested villous atrophy. In addition, 2 patients with high EMA and AGA antibody titers refused biopsy, and 4 patients with low EMA and/or AGA titers were found to have normal titers at control before biopsy decision.

CONCLUSION

Because the prevalence of CD at diagnosis of IDDM would seem to be 6% to 8%, screening for CD seems to be justified among patients with newly diagnosed IDDM.

Evidence of gastrointestinal immune reactivity in patients with sarcoidosis

OBJECTIVES

The aim of the present study was to explore the frequency of clinical and serological manifestations of gastrointestinal immune reactivity in a large group of Swedish patients with sarcoidosis.

DESIGN

In patients with documented sarcoidosis, the presence of pernicious anaemia and coeliac disease was examined. Antibodies to H+/K+ ATPase, gliadin (AGA-IgA/IgG) and endomysium (IgA-EMA) were analysed. In H+/K+ ATPase antibody-positive patients, serum gastrin levels were measured and, when elevated, gastrointestinal biopsy was offered (biopsy performed in 6/9 patients): biopsy was also offered to those with positive EMA or AGA of either class (biopsy performed in 8/12 patients). Subjects from national and local studies were used as controls.

SETTING

The patients were recruited at the Department of Pulmonary Medicine, and the study was conducted at the Department of Endocrinology, University of Lund, Malmö University Hospital, Malmö, Sweden.

SUBJECTS

Of all patients (n = 89) with documented sarcoidosis attending the Department of Pulmonary Medicine between January 1980 and December 1991, 78 [34 females and 44 males; median age at the time of the study, 48 (range 22-81) years; median observation time since the diagnosis of sarcoidosis, 120 (range 1-468) months] were examined.

RESULTS

Twenty-nine patients (37.2%) had signs of gastrointestinal immune reactivity. H+/K+ ATPase antibodies were detected in 19 patients (24.4 vs. 4% in controls, P = 0.00015). Serum gastrin levels (median 45, range 22-720 pmol L(-1)) in those patients correlated with antibody titre (r2 = 0.882). Gliadin antibodies were detected in 12 patients (15.4 vs. 8.1% in controls, P = 0.042), of whom 11 (14.1 vs. 4.5% in controls, P = 0.00114) had AGA-IgA alone. One patient had pernicious anaemia and another coeliac disease (EMA-positive).

CONCLUSION

We have demonstrated a high frequency of gastric autoimmunity and gluten-associated immune reactivity in patients with sarcoidosis, occurring in almost 40% of the cases, the former being the most frequent gastrointestinal immune manifestation. Despite a high frequency of humoral autoimmunity, the frequencies of clinical disease, pernicious anaemia and coeliac disease were not increased as compared with the control population.

Anti-alpha-gliadin antibodies (AGA) in the serum of coeliac children and controls recognize an identical collection of linear epitopes of alpha-gliadin

Anti-gliadin antibodies can be found in the serum of patients with overt and subclinical coeliac disease, but also in that of some controls. The aim of the present study was to identify the linear epitopes of the alpha-gliadin molecule to which the humoral response is directed. Therefore, the IgG and IgA antibody reactivity against an overlapping set of synthetic peptides covering the entire sequence of alpha-gliadin was measured in the sera from patients with coeliac disease, from controls with elevated titres of anti-gliadin antibodies and from healthy children using an ELISA technique. The antibodies mainly recognize peptides derived from the N-terminal region of alpha-gliadin, containing the motif QPFXXQXPY. Reactivity was also detected against two other synthetic peptides, which do not contain this motif and represent a sequence encoded further to the C-terminal region of alpha-gliadin. Anti-gliadin antibodies in sera from patients with coeliac disease and from controls recognize the same linear epitopes. Thus, serological investigation of the specificity of these antibodies using a peptide ELISA does not allow discrimination between patients and controls.

Screening for coeliac disease in adult insulin-dependent diabetes mellitus

OBJECTIVES

To study, by sequential screening for gliadin antibodies (GA) and endomysial antibodies (EMA), the prevalence and clinical characteristics of coeliac disease (CD) in adult IDDM patients.

SUBJECTS AND MEASUREMENTS

A series comprising 1664 diabetes patients [848 with IDDM, 745 with non-insulin-dependent diabetes (NIDDM) and 71 with secondary diabetes] were screened for GA. IgA- or IgG-GA positive sera were analysed for EMA.

RESULTS

IgA-GA were more frequent in all the diabetes subgroups (13.7% in IDDM,12.3% in NIDDM and 23.9% in secondary diabetes, P < 0.001 in all three cases) than among healthy blood donors (4.7%). Two patients with NIDDM had CD. Of the IDDM group (n = 848), 8 had previously diagnosed CD and 14 more (of whom 7 could be biopsied) were EMA positive. All had villous atrophy. The minimum prevalence of CD (including probable cases) in IDDM was 2.6% (22/848). Patients with previously known CD had more symptoms (P < 0.001), more deficiency states (P < 0.001) and more autoimmune diseases (P < 0.04) than those identified by screening. IDDM patients with a diabetes duration of 31-40 years were characterised by a higher prevalence of CD than patients with a duration of less than 30 years (6.7% vs. 1.7%; P < 0.02).

CONCLUSIONS

Serial analysis of GA and EMA confirmed a high prevalence of CD in adult IDDM (2.6%). False-positive IgA-GA test results are frequent in patients with diabetes, irrespective of type. EMA analysis is the preferable screening tool for CD in diabetes.

Prevalence of IgA-antigliadin antibodies and IgA-antiendomysium antibodies related to celiac disease in children with Down syndrome

OBJECTIVE

This study was undertaken to investigate the prevalence of celiac disease in children and adolescents with Down syndrome.

MATERIAL AND METHODS

Forty-three children and adolescents with Down syndrome were screened for IgA-antigliadin antibodies (AGA) and IgA-antiendomysium antibodies (EMA). Patients found to be either AGA- or EMA-positive were investigated further with intestinal biopsy.

RESULTS

None of the 43 patients had known celiac disease at entry into the study; 37% (16/43) were found to have AGA levels above normal, and 16% (7/43) to be EMA-positive. Of the 15 patients who underwent biopsy, 8 manifested villous atrophy. Villous atrophy was present in all 7 of the EMA-positive patients, whereas the villi were normal in 7 of the 13 AGA-positive patients who underwent biopsy.

CONCLUSIONS

EMA is a good immunologic marker for use in screening for celiac disease, and screening is justified in patients with Down syndrome.

Frequent occurrence of non-specific gliadin antibodies in chronic liver disease. Endomysial but not gliadin antibodies predict coeliac disease in patients with chronic liver disease

BACKGROUND

The frequency of gliadin antibody (GA) positivity has been found to be increased among patients with chronic liver disease, as has that of coeliac disease (CD). CD has also been found to be increased among patients with primary biliary cirrhosis (PBC) or primary sclerosing cholangitis (PSC).

METHODS

To investigate these relationships further, a micro-enzyme-linked immunosorbent assay and immunofluorescence tests for GAs and endomysial antibodies (EMAs) were performed in large subgroups of patients representing various chronic liver diseases and in healthy blood donors.

RESULTS

As compared with blood donors (among whom it was 5%) the frequency of IgA GA positivity was higher in all patient subgroups: alcoholic liver disease, 20% (22 of 110, P < 0.001); PBC, 16% (16 of 101, P < 0.001); PSC, 24% (19 of 80, P < 0.001); chronic hepatitis, 19% (13 of 70, P < 0.001); and hepatitis C virus infection, 11% (11 of 104, P < 0.01). Two patients with autoimmune chronic hepatitis were EMA-positive, and in both cases the presence of CD was verified by small-bowel biopsy.

CONCLUSIONS

IgA GA positivity generally occurs at increased frequency among patients with chronic liver disease and may represent non-specific immune activation. In liver disease GA testing is not useful in screening for CD, whereas the EMA test seems to be highly specific. CD is more prevalent than expected among patients with autoimmune chronic hepatitis but not among those with PBC or PSC.

Human umbilical cord as substrate for IgA antiendomysial antibodies allows large scale screening for celiac sprue

Sera from 800 patients referred to our laboratory for celiac sprue screening were tested for IgA antiendomysial antibodies on human umbilical cord (HUC-EmA) and for IgA and IgG antigliadin antibodies (AGA) on rodent tissue by indirect immunofluorescence. Thirty-three patients (4.1%) were positive for at least one of the two antibodies; IgA HUC-EmA were found in 25 patients, whereas IgA and IgG AGA were detected in 19 and 24 subjects, respectively. Twenty-seven (82%) of the 33 patients with immunological markers showed sub-total or severe partial villous atrophy consistent with celiac sprue, whereas the remaining six cases had normal histological findings. None of 30 antibody-negative biopsied patients showed abnormalities of duodenal mucosa. Of the 27 newly diagnosed celiacs, only 21 (78%) were positive for IgA and/or IgG AGA, whereas IgA HUC-EmA were found in all but two cases (93%). In these two cases, positive only for IgG AGA, celiac sprue was associated with IgA deficiency. Our study proves that the routine use of IgA HUC-EmA increases celiac sprue findings by up to 15% when compared with AGA.

Unsuspected coeliac disease in chronic 'cryptogenic' liver disease

BACKGROUND

Earlier reports have suggested that a relationship exists between chronic liver disease and coeliac disease (CD). Gliadin antibodies (GA) have been used to screen for CD.

METHODS

Using a micro-enzyme-linked immunosorbent procedure, we analysed sera from 327 consecutive patients with chronic liver disease for GA (IgA and IgG) and evaluated their clinical significance.

RESULTS

GA were detected in 19 patients (6%), a prevalence six times greater than that found in healthy blood donors. In 9 of the 19 patients the liver disease had been classified as cryptogenic. The occurrence of GA was independent of the degree of hepatocellular impairment. A diagnosis of CD was confirmed in 5 of the 10 patients who underwent small-bowel biopsy.

CONCLUSIONS

Our findings suggest the prevalence of CD in patients with chronic liver disease to be at least 1.5%--that is, 15 times higher than in the general population. They also suggest that the possible presence of CD should be considered in cases of chronic 'cryptogenic' liver disease.