Celiac disease

HLA-DQ2 / DQ8

Celiac disease is an immune-mediated reaction to gluten. It is tightly bound to two HLA class II types: almost all patients carry HLA-DQ2 or HLA-DQ8. The test therefore has above all a strong exclusion value: without either type, celiac disease is practically ruled out.

Why DQ2 and DQ8

These DQ molecules bind particularly well the deamidated gluten peptides produced by the enzyme transglutaminase. They thus present to the immune system exactly the fragments that trigger inflammation in the small intestine. Without a matching DQ molecule this first step is missing.

How to read the test

A positive DQ2/DQ8 result only means the genetic precondition is present, not that celiac disease exists. The diagnosis rests on antibodies and, where needed, a tissue sample. A negative result, by contrast, makes celiac disease very unlikely and can practically rule it out.

What Genome measures. Whether HLA-DQ2 (DQA1*05:01 / DQB1*02:01) or HLA-DQ8 (DQB1*03:02) are present in the HLA typing, as risk or exclusion context.

Related topics

HLA and autoimmunityType 1 diabetesHLA typing

Sources

  1. 1Abadie et al., 2011 Integration of genetic and immunological insights into a model of celiac disease pathogenesis. Annual Review of Immunology 29:493–525. doi.org/10.1146/annurev-immunol-040210-092915
  2. 2Husby et al., 2020 European Society Paediatric Gastroenterology, Hepatology and Nutrition guidelines for diagnosing coeliac disease. Journal of Pediatric Gastroenterology and Nutrition 70:141–156. doi.org/10.1097/MPG.0000000000002497