What role does HLA-DQ2 play in allergy?

HLA-DQ2 is a human leukocyte antigen (HLA) class II gene that plays a key role in immune recognition by presenting antigen fragments to T-helper cells. Its strongest and most established association is not with allergy but with autoimmunity: specific variants (HLA-DQ2.5) are strongly linked to celiac disease, an autoimmune reaction to gluten. For allergies—IgE-mediated hypersensitivity—the evidence for a direct role of HLA-DQ2 is much weaker. Some studies suggest associations with certain food allergies or atopic conditions, but findings are inconsistent and often confounded by other HLA genes or environmental factors. In clinical practice, HLA-DQ2 testing is used for celiac disease risk assessment, not for allergy diagnosis. Confirming an allergy requires specific IgE tests or oral food challenges. The evidence for HLA-DQ2 involvement in allergy is best described as 'unclear' due to contradictory data and lack of clinical utility.