Celiac disease, wheat allergy, and gluten sensitivity: when gluten free is not a fad.

As the gluten-free diet (GFD) gains in popularity with the general public, health practitioners are beginning to question its real health benefits. For those patients with celiac disease (CD), the GFD is considered medical nutrition therapy, as well as the only proven treatment that results in improvements in symptomatology and small bowel histology. Those with wheat allergy also benefit from the GFD, although these patients often do not need to restrict rye, barley, and oats from their diet. Gluten sensitivity is a controversial subject, where patients who have neither CD nor wheat allergy have varying degrees of symptomatic improvement on the GFD. Conditions in this category include dermatitis herpetiformis (DH), irritable bowel syndrome (IBS), and neurologic diseases such as gluten-sensitive ataxia and autism. It is important for patients and healthcare practitioners to understand the differences between these conditions, even though they may all respond to a GFD. Patients with CD can experience comorbid nutrition deficiencies and are at higher risk for the development of cancers and other autoimmune conditions. Those with wheat allergy and gluten sensitivity are thought not to be at higher risk for these complications. Defining the symptoms and biochemical markers for gluten-sensitive conditions is an important area for future investigations, and high-quality, large-scale randomized trials are needed to prove the true benefits of the GFD in this evolving field.

Stratifying risk for celiac disease in a large at-risk United States population by using HLA alleles.

BACKGROUND & AIMS: Susceptibility to celiac disease (CD) is related to HLA-DQ2 and DQ8 alleles and the heterodimers they encode. The objective of this study was to stratify risk for CD on the basis of HLA-DQ genotype. METHODS: DNA from 10,191 subjects who are at risk for CD was analyzed for HLA-DQ haplotypes. Individuals with CD were identified as those who tested positive for anti-endomysial immunoglobulin A (EMA+) in an immunofluorescence assay. RESULTS: Samples homozygous for DQ2.5 (HLA-DQA1 05-DQB1 02) or DQ2.2/DQ2.5 (HLA-DQA1 05-DQB1 02 and HLA-DQA1 0201-DQB1 02) comprised 5.38% of the total; 28.28% of these were EMA+ (95% confidence interval [CI], 24.55-32.26). Of the samples that were DQ2.5 heterozygous (HLA-DQA1 05-DQB1 02); 9.09% were EMA+ (95% CI, 7.82-10.51). Among samples in which HLA-DQ8 (HLA-DQA1 03-DQB1 0302) was detected, 8.42% of homozygotes (95% CI, 3.71-15.92) and 2.11% of heterozygotes (95% CI, 1.43-3.00) were EMA+. Samples with DQ2.2/DQ8 or DQ2.5/DQ8 comprised 5.08% of the total, and 11.78% of these were EMA+ (95% CI, 9.13-14.87). HLA-DQ2 and HLA-DQ8 were absent in 4283 samples (42.03% of the total); 0.16% of these samples were EMA+ (95% CI, 0.07-0.34). CONCLUSIONS: High-resolution, sequence-specific oligonucleotide probe typing with 35 DQA1-specific and 37 DQB1-specific probes of DNA from more than 10,000 subjects was used to stratify risk of CD in an at-risk U.S. population. DQ2 homozygosity (DQ2.5/DQ2.2+2.5) increased risk for CD, estimated by the rate of EMA positivity, compared with the entire sample population and other DQ genotypes. These data suggest a quantitative relationship between the type/proportion of DQ heterodimers and the risk of CD and identify potential immunotherapeutic targets.

Zonulin upregulation is associated with increased gut permeability in subjects with type 1 diabetes and their relatives.

Zonulin, a protein that modulates intestinal permeability, is upregulated in several autoimmune diseases and is involved in the pathogenesis of autoimmune diabetes in the BB/Wor animal model of the disease. To verify the association between serum zonulin levels and in vivo intestinal permeability in patients with type 1 diabetes, both parameters were investigated in different stages of the autoimmune process. Forty-two percent (141 of 339) of the patients had abnormal serum zonulin levels, as compared with age-matched control subjects. The increased zonulin levels correlated with increased intestinal permeability in vivo and changes in claudin-1, claudin-2, and myosin IXB genes expression, while no changes were detected in ZO1 and occludin genes expression. When tested in serum samples collected during the pre-type 1 diabetes phase, elevated serum zonulin was detected in 70% of subjects and preceded by 3.5 +/- 0.9 years the onset of the disease in those patients who went on to develop type 1 diabetes. Combined, these results suggest that zonulin upregulation is associated with increased intestinal permeability in a subgroup of type 1 diabetic patients. Zonulin upregulation seems to precede the onset of the disease, providing a possible link between increased intestinal permeability, environmental exposure to non-self antigens, and the development of autoimmunity in genetically susceptible individuals.

Follow-up of patients with celiac disease: achieving compliance with treatment.

Celiac disease is the only autoimmune condition for which we know the environmental trigger: gluten. Complete removal of gluten from the diet in a patient with celiac disease should result in symptomatic, serologic, and histologic remission. However, compliance with the gluten-free diet, especially in the United States, is extremely challenging. Compliance can be measured both noninvasively, by dietary history and measurement of serum antibodies, and invasively, by using endoscopic and histologic criteria. The advantages and disadvantages of these various modalities are discussed. The highest rates of compliance are reported in patients who are diagnosed as young children, whereas adolescents and those diagnosed via mass serologic screening have the most transgressions. Barriers to compliance include the poor palatability of gluten-free foods, confusing food-labeling practices, and common comorbid psychologic burdens such as anxiety and depression. Because celiac disease is a multisystemic disorder, physicians need to be aware of the potential autoimmune, nutritional, and malignant complications. An algorithm for the follow-up and management of the newly diagnosed celiac disease patient is presented, which includes regular follow-up; measurement of serum antibodies; eliciting a detailed dietary history; and examination for signs and symptoms of nutritional deficiencies, malignancy, and other autoimmune diseases. Ideally, a team approach to the follow-up of the newly diagnosed patient should include regular supervision by an interested physician, medical nutritional counseling by a registered dietician, and access to local and national support groups knowledgeable about this condition.

Prevalence of celiac disease in at-risk and not-at-risk groups in the United States: a large multicenter study.

BACKGROUND: Celiac disease (CD) is an immune-mediated enteropathic condition triggered in genetically susceptible individuals by the ingestion of gluten. Although common in Europe, CD is thought to be rare in the United States, where there are no large epidemiologic studies of its prevalence. The aim of this study was to determine the prevalence of CD in at-risk and not-at-risk groups in the United States. METHODS: Serum antigliadin antibodies and anti-endomysial antibodies (EMA) were measured. In EMA-positive subjects, human tissue transglutaminase IgA antibodies and CD-associated human leukocyte antigen DQ2/DQ8 haplotypes were determined. Intestinal biopsy was recommended and performed whenever possible for all EMA-positive subjects. A total of 13 145 subjects were screened: 4508 first-degree and 1275 second-degree relatives of patients with biopsy-proven CD, 3236 symptomatic patients (with either gastrointestinal symptoms or a disorder associated with CD), and 4126 not-at-risk individuals. RESULTS: In at-risk groups, the prevalence of CD was 1:22 in first-degree relatives, 1:39 in second-degree relatives, and 1:56 in symptomatic patients. The overall prevalence of CD in not-at-risk groups was 1:133. All the EMA-positive subjects who underwent intestinal biopsy had lesions consistent with CD. CONCLUSIONS: Our results suggest that CD occurs frequently not only in patients with gastrointestinal symptoms, but also in first- and second-degree relatives and patients with numerous common disorders even in the absence of gastrointestinal symptoms. The prevalence of CD in symptomatic patients and not-at-risk subjects was similar to that reported in Europe. Celiac disease appears to be a more common but neglected disorder than has generally been recognized in the United States.