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Celiac.com 01/20/2024 - The tissue transglutaminase IgA antibodies (tTG-IgA) test is a crucial diagnostic tool for celiac disease. In individuals with celiac disease, the ingestion of gluten triggers an immune response, leading to the production of antibodies, including tTG-IgA. These antibodies target the tissues of the small intestine, causing damage and inflammation. The tTG-IgA test measures the levels of these specific antibodies in the blood. Elevated tTG-IgA levels are indicative of an active immune response to gluten and suggest the presence of celiac disease. This blood test is an essential component of the diagnostic process, helping healthcare providers identify individuals who may require further evaluation, such as genetic testing and an endoscopic biopsy, to confirm the diagnosis of celiac disease. Elevated tissue transglutaminase IgA antibodies (tTG-IgA) are primarily associated with celiac disease, but they can also be elevated in some other conditions. It's important to note that the presence of elevated antibodies alone doesn't diagnose a specific condition, and further clinical evaluation is needed. Conditions and factors that may lead to elevated tTG-IgA antibodies may include the following: Non-Celiac Gluten Sensitivity (NCGS) Wheat Allergy Inflammatory Bowel Diseases (IBD) Type 1 Diabetes Autoimmune Liver Diseases Rheumatoid Arthritis Thyroid Disorders Genetic Conditions Casein/Cow's Milk Intolerance Non-Celiac Gluten Sensitivity (NCGS) Although it doesn't involve the autoimmune response seen in celiac disease, NCGS can lead to symptoms similar to those of celiac disease and may be associated with elevated tTG-IgA. NCGS is characterized by gluten-related symptoms without the autoimmune response and intestinal damage seen in celiac disease. The exact mechanisms leading to elevated tTG-IgA in NCGS are not fully understood, but it's believed that gluten sensitivity in NCGS may still induce an immune response, even though it differs from the autoimmune process seen in celiac disease. The presence of elevated tTG-IgA in NCGS underscores the complexity of gluten-related disorders and highlights the need for further research to elucidate the underlying immune responses and mechanisms associated with different gluten-related conditions. Wheat Allergy Individuals with a wheat allergy may produce antibodies, including tTG-IgA, as part of the allergic response. Individuals with a wheat allergy may also exhibit increased tTG-IgA levels. Wheat allergy is an immune-mediated response to proteins in wheat, distinct from the autoimmune nature of celiac disease. The presence of elevated tTG-IgA in individuals with a wheat allergy is somewhat perplexing, as tTG is an enzyme involved in the pathology of celiac disease, and its elevation is not commonly associated with allergies. One possible explanation is that the immune response triggered by a wheat allergy might lead to some cross-reactivity or shared epitopes with components involved in celiac disease, causing an increase in tTG-IgA. However, the exact mechanisms behind this phenomenon are not well-elucidated, and more research is needed to understand the connections between wheat allergy and the elevation of tTG-IgA. It emphasizes the intricate interplay between the immune system and various wheat-related disorders, requiring further exploration to unravel the complexities of immune responses in these conditions. Inflammatory Bowel Diseases (IBD) Conditions such as Crohn's disease and ulcerative colitis can cause gastrointestinal inflammation, and elevated tTG-IgA levels have been reported in some individuals with IBD. Elevated tissue transglutaminase IgA antibodies (tTG-IgA) can also be observed in individuals with Inflammatory Bowel Diseases (IBD). IBD, which includes conditions like Crohn's disease and ulcerative colitis, involves chronic inflammation of the gastrointestinal tract. The link between IBD and elevated tTG-IgA is not as straightforward as in celiac disease, and the reasons behind this elevation in some IBD patients remain a subject of research. One hypothesis suggests that the chronic inflammation and alterations in the intestinal mucosa associated with IBD may lead to increased permeability of the gut barrier. This heightened permeability might allow gluten proteins to interact with the immune system in a way that triggers the production of tTG-IgA. The intricate relationship between IBD and tTG-IgA elevation underscores the complex interplay between autoimmune responses and gastrointestinal disorders, requiring further investigation to uncover the underlying mechanisms and clinical implications. Type 1 Diabetes Some individuals with type 1 diabetes may have elevated tTG-IgA antibodies, and there is an increased risk of celiac disease in individuals with diabetes. Elevated tissue transglutaminase IgA antibodies (tTG-IgA) can be found in individuals with Type 1 Diabetes (T1D), establishing a connection between these two autoimmune conditions. Both celiac disease and Type 1 Diabetes involve an autoimmune response, where the body's immune system mistakenly targets its own tissues. In the case of celiac disease, the immune system reacts to gluten, while in Type 1 Diabetes, it attacks the insulin-producing cells in the pancreas. The shared genetic susceptibility to autoimmune disorders could explain the co-occurrence of celiac disease and Type 1 Diabetes. The presence of certain genetic markers might predispose individuals to develop multiple autoimmune conditions. Additionally, environmental factors and common triggers in the immune response pathways could contribute to the simultaneous development of these disorders. Clinicians often monitor individuals with Type 1 Diabetes for celiac disease-related antibodies, including tTG-IgA, to identify and manage celiac disease early, highlighting the importance of understanding these interconnected autoimmune processes for comprehensive patient care. Thyroid Disorders Conditions such as autoimmune thyroiditis (Hashimoto's thyroiditis) and Graves' disease may be associated with elevated tTG-IgA antibodies. Elevated tissue transglutaminase IgA antibodies (tTG-IgA) can be associated with thyroid disorders, particularly autoimmune thyroid conditions such as Hashimoto's thyroiditis. Hashimoto's thyroiditis is an autoimmune disease where the immune system attacks the thyroid gland, leading to inflammation and potential impairment of thyroid function. The link between celiac disease and autoimmune thyroid disorders has been observed, suggesting a shared genetic predisposition for autoimmune conditions. Individuals with celiac disease may have an increased risk of developing autoimmune thyroid disorders, and vice versa. The interconnected nature of autoimmune diseases suggests that the immune system's response to gluten in celiac disease might trigger or exacerbate autoimmune reactions in other organs, including the thyroid. Monitoring thyroid function and related antibodies, such as tTG-IgA, is crucial in individuals with celiac disease to identify and manage potential thyroid complications early. Understanding these complex interactions between autoimmune disorders is essential for comprehensive patient care and effective management of associated health conditions. Autoimmune Liver Diseases Certain autoimmune liver diseases, such as autoimmune hepatitis and primary biliary cirrhosis, may be associated with elevated tTG-IgA antibodies. Elevated tissue transglutaminase IgA antibodies (tTG-IgA) may be detected in individuals with autoimmune liver diseases, particularly autoimmune hepatitis (AIH). Autoimmune hepatitis is a chronic inflammatory condition where the body's immune system erroneously attacks liver cells, leading to liver inflammation and potential damage. The connection between celiac disease and autoimmune liver diseases, although not fully understood, suggests shared autoimmune mechanisms. In some cases, individuals with celiac disease may experience immune system dysregulation that extends beyond the small intestine, leading to autoimmune reactions in other organs such as the liver. The presence of elevated tTG-IgA in individuals with autoimmune liver diseases underscores the complex interplay between various autoimmune conditions. Monitoring liver function and related antibodies is essential for comprehensive healthcare in individuals with celiac disease, as the autoimmune cascade can impact multiple organs. Understanding these connections aids in early detection, proper management, and improved overall outcomes for individuals with autoimmune liver diseases and concurrent celiac disease. Genetic Conditions Some genetic conditions, such as Down syndrome, may be associated with an increased prevalence of celiac disease and elevated tTG-IgA. Elevated tissue transglutaminase IgA antibodies (tTG-IgA) in individuals with genetic conditions such as Down syndrome can be attributed to the increased prevalence of autoimmune disorders in this population. Down syndrome, characterized by the presence of an extra copy of chromosome 21, is associated with a higher susceptibility to autoimmune conditions, including celiac disease. The genetic link between Down syndrome and celiac disease suggests a shared vulnerability to immune dysregulation. Individuals with Down syndrome may exhibit an elevated risk of developing autoimmune disorders due to alterations in immune system function associated with the genetic anomaly. The complex relationship between genetics and autoimmune responses underscores the importance of monitoring individuals with Down syndrome for various health conditions, including celiac disease. Early detection and management of celiac disease in individuals with Down syndrome are crucial for optimizing their overall health and well-being, considering the potential impact of untreated celiac disease on nutrient absorption and long-term health outcomes. Rheumatoid Arthritis Elevated tTG-IgA levels have been reported in some individuals with rheumatoid arthritis. The presence of elevated tissue transglutaminase IgA antibodies (tTG-IgA) in individuals with rheumatoid arthritis (RA) can be linked to the complex interplay between autoimmune disorders. Rheumatoid arthritis is a chronic inflammatory condition primarily affecting the joints, but it is increasingly recognized that individuals with RA may have an elevated risk of coexisting autoimmune diseases, including celiac disease. The shared genetic predisposition and immune dysregulation mechanisms contribute to the observed association between RA and elevated tTG-IgA. In the context of rheumatoid arthritis, the immune system mistakenly attacks the joints, leading to inflammation and joint damage. This dysregulated immune response may extend beyond the joints and manifest as an increased susceptibility to other autoimmune conditions, such as celiac disease. The identification of elevated tTG-IgA in individuals with RA underscores the importance of comprehensive health assessments in autoimmune disorders, as coexisting conditions may impact the overall management and prognosis of these individuals. Regular monitoring and collaboration between healthcare providers specializing in different autoimmune diseases are crucial for a holistic approach to patient care. Casein/Cow's Milk Intolerance Recent studies have shown that elevated tTG-IgA levels have been reported in some individuals with casein/cow's milk intolerance. Conclusion While it's true that elevated tissue transglutaminase IgA antibodies (tTG-IgA) can be associated with various conditions beyond celiac disease, including autoimmune disorders and genetic conditions, the tTG-IgA test remains a valuable tool in the diagnosis of celiac disease. In individuals with celiac disease, there is a specific immune response triggered by the ingestion of gluten, a protein found in wheat, barley, and rye. People with celiac disease often have higher levels of tTG-IgA in their blood due to the immune system's reaction to gluten. When gluten is ingested, individuals with celiac disease produce antibodies, including tTG-IgA, which target and attack the tissues of the small intestine. The elevated tTG-IgA levels are indicative of this immune response and the damage occurring in the intestinal lining. However, it's important to note that the interpretation of tTG-IgA levels should be done in the context of the individual's overall health, medical history, and the possibility of other conditions. A definitive diagnosis of celiac disease typically involves a combination of blood tests, genetic testing (HLA-DQ2 and HLA-DQ8), and, in some cases, an endoscopic biopsy of the small intestine. In summary, while elevated tTG-IgA levels are a common feature in celiac disease, the diagnosis involves a comprehensive assessment, and healthcare providers consider various factors to ensure accurate identification of the condition. It's crucial to interpret antibody test results in the context of the individual's clinical symptoms, medical history, and additional diagnostic tests. If tTG-IgA antibodies are elevated, further evaluation by a healthcare professional, typically including endoscopic procedures and biopsies, is often necessary to confirm or rule out celiac disease.

Celiac.com 03/30/2023 - A study recently published in the Journal of the American Academy of Dermatology shows that people with psoriasis have twice the odds of having celiac disease compared to those without psoriasis. The study is the work of a research team that included Marina Z. Joel, BS; Ryan Fan, BA; and Jeffrey M. Cohen, MD. They are variously affiliated with the Johns Hopkins University School of Medicine, Baltimore, Maryland; the Yale School of Medicine, and the Department of Dermatology at Yale School of Medicine, New Haven, Connecticut. The Psoriasis & Celiac Disease Study For their study, the Ms. Joel and her colleagues examined the association between psoriasis and celiac disease. They used data from 316,166 adults, and found that of the 6,476 patients with psoriasis, 1.65% had celiac disease compared to nearly 0.5% of 309,690 patients without psoriasis. The study controlled for various factors such as age, sex, race and ethnicity, smoking status, autoimmune diseases linked to psoriasis and celiac disease, and body mass index (BMI), and found that psoriasis remained significantly associated with celiac disease. Study Findings The authors note that while the exact mechanism behind this association is unclear, genome-wide association studies have found that many susceptibility loci for psoriasis overlap with those for celiac disease: “While the pathophysiologic mechanism behind the association between psoriasis and celiac disease is unclear, several explanations have been proposed. Genome-wide association studies have found that many susceptibility loci for psoriasis overlap with those for celiac disease," they write. They add that "both psoriasis and celiac disease are T-cell driven disorders, there could be shared immunogenic mechanisms between the two conditions." Although more research is needed to fully understand the link between psoriasis and celiac disease, studies that help to document connections between celiac disease and other disorders are very helpful in clarifying the overall celiac disease puzzle. Read more in Journal of the American Academy of Dermatology

Celiac.com 07/12/2021 - When doctors test symptomatic children for celiac disease, they currently order biopsy confirmation only for children whose anti-transglutaminase IgA (TGA-IgA) titers exceed the upper limit of normal (ULN), and below 10 times the upper limit of normal. Any results below the ULN do not normally get referred for a biopsy. Now, this works pretty well in the sense that a high percentage of biopsies for such patients come up positive. However, the management of children with lower TGA-IgA values presents a clinical challenge. What about children who test just under the ULN cut off? Especially those with symptoms, however mild. Do persistently low positive TGA-IgA titers have any diagnostic value for predicting celiac disease in children? A team of researchers recently looked into this question. The research team included Chiara Marja Trovato; Monica Montuori; Annalisa Morelli; Danilo Alunni Fegatelli; Annarita Vestri; Carla Giordano; Salvatore Cucchiara; Giocomo Caio; and Salvatore Oliva. They are variously affiliated with the Pediatric Gastroenterology and Liver Unit, Maternal and Child Health Department; the Department of Statistical Science; and the Department of Radiological, Oncological and Pathological Sciences at Sapienza University of Rome; along with the Department of Medical Sciences at the University of Ferrara in Ferrara, Italy. The team retrospectively analyzed children with symptoms or signs of celiac disease, not eligible for a no-biopsy approach. Their study included children with at least two TGA-IgA measurements, endomysial antibody (EMA) assessment and esophagogastroduodenoscopy with biopsies. TGA-IgA values were provided as multiples of ULN. The team grouped patients according to median TGA-IgA values: Group A included TGA-IgA>1 ≤ 5 × ULN; defined as “low-positive”, Group B (TGA-IgA > 5 < 10 × ULN; “moderate-positive”), and Group C, the controls). They were able to analyze the data of 281 children. Of 162 children in group A, they diagnosed celiac disease in 142 (nearly 90%), whereas they found normal duodenal mucosa in 20 group A children. The team diagnosed all 62 children (100%) in group B with celiac disease. Group C included 57 control subjects. EMA were undetectable in 31 (15%) of mucosal atrophy cases. On the receiver-operating characteristic curve, with the area under the curve equal to 0.910, a mean value of 1.7 ULN predicted mucosal damage with nearly 82% sensitivity and specificity. Based on their data, the team concludes that repeated low or moderate TGA-IgA values, under 5 ULN or 10 ULN, are good predictors of a celiac disease diagnosis. The team advises doctors treating symptomatic children with persistently low positive TGA-IgA titers to conduct an esophagogastroduodenoscopy, regardless of the patient's EMA status. Read more in the Journal of Pediatric Gastroenterology and Nutrition