Crawley, Cæcilie

ABSTRACT Coeliac disease (CeD) and immunoglobulin A deficiency (IgAD) frequently co‐occur and share a genetic background within the HLA‐DQ2 region. Although this has been known for decades, the underlying mechanisms linking the two conditions remain unclear. We conducted a scoping review to evaluate the prevalence, clinical characteristics, diagnostic challenges and histopathological features of IgAD in patients with CeD. Thirty‐one studies published between 1985 and 2024 were included. IgAD was more prevalent among individuals with CeD, 1.4%–4.8% than in the general population, and CeD occurred in 5.9%–14.1% of patients with IgAD. Most patients presented with gastrointestinal symptoms, although selection bias was common. IgG‐based serology remains essential for diagnosis and monitoring, but its reliability during follow‐up is limited by the slow decline of antibodies. Histological findings indicate compensatory IgM and IgG responses and persistent mucosal immune activation. Improved strategies for diagnosis and long‐term monitoring of patients with both conditions are warranted.

Abstract Background Celiac disease (CeD) has an estimated prevalence of 1%–3%. The classical clinical presentation is malabsorption, but now patients may present with more subtle symptoms such as constipation, osteoporosis, or iron deficiency anemia. Children may also present with poor growth. CeD has a strong genetic component, and high-risk groups include first-degree relatives with CeD, patients with co-existing autoimmune diseases, and patients with chromosomal aberrations. Content Diagnostic tests for CeD include duodenal histology, serology, and genetic testing. Duodenal histology has traditionally been the gold standard of diagnosis. However, serological tests, especially IgA tissue transglutaminase antibodies (TTG-IgA), are widely used and diagnostic algorithms are based primarily on TTG-IgA as a starting point. Human leukocyte antigen typing may also be incorporated to determine genetic risk for CeD. Guidelines for children endorse biopsy avoidance provided high levels of TTG-IgA, with diagnostic accuracy being comparable to duodenal biopsy. Confirmation may be achieved by identifying IgA endomysial antibodies in a separate blood sample. Subjects with low positive TTG-IgA levels and subjects with IgA deficiency need a biopsy to establish a diagnosis of CeD. The clinical follow-up of CeD usually includes a repeat TTG-IgA examination. In adults, healing may be delayed or incomplete, and a rare consequence of refractory celiac disease is transformation to enteric T-cell lymphoma. Summary Laboratory testing, in particular TTG-IgA, plays a central role in the diagnosis and has an accuracy comparable to histology. Diagnostic algorithms utilizing laboratory testing are critical for the development of novel strategies to improve diagnosis.

AbstractBackgroundThe popularity of the gluten‐free diet and sales of gluten‐free products have increased immensely.AimsTo investigate whether gluten induces gastrointestinal symptoms, measured by self‐reported questionnaires, as well as mental health symptoms in adolescents from a population‐based cohort.MethodsThe eligible participants (n = 273) were recruited from a population‐based cohort of 1266 adolescents and had at least four different gastrointestinal symptoms. Phase one (n = 54) was a run‐in phase where the participants lived gluten‐free for 2 weeks. If they improved they continued to phase 2 (n = 33), a blinded randomised cross‐over trial. Participants were blindly randomised either to start with 7 days of gluten, eating two granola bars containing 10 g of gluten or to 7 days on placebo, eating two granola bars without gluten, followed by the reverse and separated by a 7‐day washout period. The effects of the intervention on gastrointestinal symptoms and mental health symptoms were assessed.ResultsIn total, 54/273 participants entered the run‐in phase and 35 were eligible for randomization. A total of 33 were randomised and 32 completed the trial. The median age was 20.3 (IQR 19.2–20.9) and 32/33 participants were females. Compared with a placebo, gluten did not induce gastrointestinal symptoms. The difference in the average VAS was −0.01 (95% confidence interval −2.07 to 2.05). Nor did we find a difference in the outcomes measuring mental health.ConclusionCompared with placebo, adding gluten to the diet did not induce gastrointestinal symptoms or worsened mental health in adolescents recruited from a population‐based cohort. The trial registration number is NCT04639921.

ABSTRACT Objectives: The objective of this study was to establish an unselected cohort of Danish adolescents and estimate the prevalence of undiagnosed celiac disease (CeD). Methods: The Glutenfunen cohort participants were recruited from an unselected subsample of the Danish National Birth Cohort, defined as participants living in the Island of Funen, Denmark. We invited all 7431 eligible participants in the age range of 15 to 21 years to a clinical visit. CeD diagnosis was based on screening with IgA transglutaminase antibodies (TG2‐IgA) and if positive, was followed by duodenal biopsies compatible with CeD (Marsh 2–3). We calculated the prevalence of CeD in the Glutenfunen cohort as the number of CeD cases diagnosed before and during the study divided by the number of participants in the Glutenfunen cohort. Results: We included 1266 participants in the Glutenfunen cohort (17%, 1266/7431). 1.1% (14 of 1266 participants) had CeD diagnosed before entering the cohort and based on the Danish National Patient Register, 0.2% of the nonparticipants (14 of 6165) had a diagnosis of CeD. In total, 2.6% (33 participants) had TG2 IgA above the upper limit of normal. Nineteen participants had duodenal biopsies compatible with CeD. The prevalence of CeD in the Glutenfunen cohort was 2.6% [(14 + 19)/1266]. Conclusions: Our study suggests that CeD is much more common than expected among Danish adolescents, comparable to other European countries, and that the majority were asymptomatic or oligosymptomatic and were only found because of the screening procedure.