Gluten Intolerance Testing
Coeliac disease is an immune-mediated disease of the intestines that is triggered by the ingestion of gluten in genetically susceptible individuals.
Genetic predisposition does play a key role in this condition, and it is well known that it is strongly associated with specific HLA class II genes known as HLA-DQ2 and HLA-DQ8. Approximately 95% of patients with this condition express HLA-DQ2, and the remaining patients are usually HLA-DQ8 positive. The negative predictive value for both tests is higher than 99%. However, the HLA-DQ2 allele is carried by approximately 30% of Caucasian individuals. Thus, HLA-DQ2 or HLA-DQ8 is necessary for disease development but is not sufficient for disease development.
There are mechanisms called epigenetics that include gene methylation and histone modification that can switch genes on and off resulting in development of condition at some point in life.
In the London Allergy and Immunology Centre we can test for antibodies and do genetic testing.
Avoidance strategy needs to be based on clinical symptoms, positive laboratory tests that include Gliadin, Reticulin, Endomysial and tissue transglutaminase antibodies of IgG and IgA type that can be detected if the patient has high gluten consumption. If a patient has been on a gluten-free diet for 6-12 months, approximately 80% will lose their antibody response. After 5 years this increases to >90%.
Consultation with gastroenterologist is required if symptoms persist after 3 months on a gluten free diet.
Gluten is present in wheat (including spelt, kamut, triticale), barley, and rye. Oats are not related to gluten-containing grains. They don’t contain gluten, but rather proteins called avenins that are tolerated by most people with gluten related problems (less than 1% of coeliac patients show a reaction to a large amount of oats in their diets). Many standard oats are produced in the same place as wheat barley and rye and can cause problems.