The current standard for a celiac disease diagnosis is a positive blood test for specific antibodies, followed by a biopsy of the intestine that reveals damage to the villi (villous atrophy). These tests are certainly invasive and unpleasant, but more than that, they are useless in cases where a patient is already following a gluten-free diet. These patients must then undergo a “gluten challenge” of up to eight weeks, during which time they reintroduce gluten-containing foods into their diet, and suffer the consequences. Only then will the blood test and biopsy accurately reveal the hallmarks necessary for an accurate diagnosis.
Funded in part by ImmusanT, a clinical development-stage biotechnology company and sponsor of the Celiac Disease Foundation, researchers in Norway decided to look to the behavior of gluten-specific immune cells (T-cells) as a means of identifying individuals with celiac disease. In a study to be published in an upcoming issue of Gastroenterology, Sarna et al. assessed the reactions of blood samples to an HLA-DQ-gluten tetrameter test. The study involved 143 individuals with genotype HLA-DQ2.5, a characteristic which makes celiac disease a possibility. The participants were divided into four groups: those with a confirmed celiac disease diagnosis who were following a gluten-free diet (62); those with a confirmed diagnosis who were NOT following a gluten-free diet (10); those for whom celiac disease had been ruled out but who were nonetheless following a gluten-free diet (19); and a control group of 52 without celiac disease and who were consuming a gluten-containing diet. Several other variables (smoking, age, BMI, etc.) were largely stable across all groups.
Each participant provided a blood sample which was assigned a number to blind the study; all samples were tested using a newly-developed HLA-DQ-gluten tetrameter assay. Considerable statistical analysis was performed on the data, and researchers concluded that the test was an effective diagnostic tool. Interestingly, while the test was able to predict the presence of celiac disease in about 2/3 of cases, it was nearly 100% accurate in its ability to predict the absence of the disease, regardless of whether or not a patient was following a gluten-free diet. Simply stated, use of this test could quickly and easily eliminate the possibility of celiac disease for a majority of patients, leaving only a small percentage to undergo the traditional path of gluten-challenge followed by blood testing and intestinal biopsy to confirm diagnosis.
HLA-DQ-gluten tetrameter testing is not yet widely available, and additional studies of its sensitivity and specificity are necessary. It is clear, however, that testing of this type will be a powerful addition to the clinician’s diagnostic toolbox, one that is effective regardless of a patient’s diet.
To read the entire study, please click here.
New Testing Option for Possible Celiac Disease Sufferers