A new blood test offers an easier way to detect or rule out celiac in people who already avoid gluten. The HLA-DQ-gluten tetramer test identifies celiac immune cells that do not go away on a gluten-free diet.
Norwegian researchers tested 62 people with celiac on a gluten-free diet, 10 who were still consuming gluten, 19 with non-celiac gluten sensitivity (NCGS) and 52 presumed-healthy individuals for comparison. The test identified 97 percent of celiac patients on a gluten-free diet and 100 percent on a normal diet. It detected no immune cells in NCGS or healthy people.
A negative test result reliably proves the absence of celiac. However, a small minority of healthy people receive a positive result. A follow-up gluten challenge and further tests may be required to confirm diagnosis or possibly still rule out celiac.
In untreated patients on a regular diet, the test performs comparably well to those currently used for initial screening. Larger studies are needed to validate results. The authors do not recommend the test for children yet because the study took blood samples too large to be safe for children.
Many experts emphasize the need for accurate diagnosis of celiac. However, patients who suspect they have celiac sometimes go on a gluten-free diet immediately before getting diagnosed. Conventional diagnostic tools cannot detect the disease once blood antibodies have returned to normal and the intestine has healed.
Many patients in this condition are unwilling to do a gluten challenge in order to get diagnosed. With the new test, people sensitive to gluten could get closer to an answer without making themselves sick.
¹Sarna VK, Lundin KEA, Mørkrid L, Qiao SW, Sollid LM, Christophersen A. HLA-DQ-gluten tetramer blood test accurately identifies patients with and without celiac disease in absence of gluten consumption. Gastroenterology, 14 Nov 2017, doi:10.1053/j.gastro.2017.11.006 [Epub ahead of print].
Vitamin D against leaky gut2,3
Vitamin D might help treat gluten disorders by maintaining health of the small intestine. Chinese researchers showed it prevents leaky gut in gluten-sensitive mice.
Leaky gut plays a role in the onset of celiac. An early stage of inflammation opens tight junctions between cells in the gut lining. This allows gluten to cross the boundary. In underlying tissue, celiac antibodies recognize gluten as an intruder and attack it, damaging the intestine in the process.
In this study, vitamin D restored tight junctions in mice exposed to gluten. This could prevent the protein from causing further
Italian scientists commenting on the Chinese study point out that leaky gut occurs in other gluten-related disorders, notably NCGS. Although gluten does not provoke autoimmune disease in these cases, large particles may still cross the gut lining and cause inflammation. The experts theorize vitamin D could treat these conditions, too, and even make gluten consumption safe for people who do not have celiac.
Such treatments have not been tested in humans. Since vitamin D is already known to be safe and widely used to support bone health and the immune and nervous systems, the Italian group expresses hope this can quickly go to clinical trial.
²Dong S, Singh TP, Wei X, Yao H, Wang H. Protective effect of 1,25-dihydroxy vitamin D3 on pepsin-trypsin-resistant gliadin-induced tight junction injuries. Dig Dis Sci, Jan 2018;63(1):92-104, doi: 10.1007/s10620-017-4738-0.
³Scricciolo A, Roncoroni L, Lombardo V, Ferretti F, Doneda L, Elli L. Vitamin D3 versus gliadin: a battle to the last tight junction. Jan 2018;63(1):1-3, doi: 10.1007/s10620-017-4848-8.
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