Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force report [IgG4-Bestimmungen gegen Nahrungsmittel werden nicht zur Diagnostik empfohlen: Positionspapier der European Academy of Allergology and Clinical Immunology (EAACI)]
Stapel S.O.,Laboratory of Allergy |
Stapel S.O.,EAACI Interest Group Allergy Diagnosis |
Asero R.,Ambulatorio di Allergologia |
Asero R.,EAACI Interest Group Food Allergy |
And 10 more authors.
LaboratoriumsMedizin | Year: 2010
Serological tests for immunoglobulin G4 (IgG4) against foods are persistently promoted for the diagnosis of food-induced hypersensitivity. Because many patients believe that their symptoms are related to food ingestion without diagnostic confirmation of a causal relationship, tests for food-specific IgG4 represent a growing market. Testing for blood IgG4 against different foods is performed with large-scale screening for hundreds of food items by enzyme-linked immunosorbent assay-type and radioallergosorbent-type assays in young children, adolescents and adults. However, many serum samples show positive IgG4 results without corresponding clinical symptoms. These findings, combined with the lack of convincing evidence for histamine-releasing properties of IgG4 in humans, and lack of any controlled studies on the diagnostic value of IgG 4 testing in food allergy, do not provide any basis for the hypothesis that food-specific IgG4 should be attributed with an effector role in food hypersensitivity. In contrast to the disputed beliefs, IgG4 against foods indicates that the organism has been repeatedly exposed to food components, recognized as foreign proteins by the immune system. Its presence should not be considered as a factor which induces hypersensitivity but rather as an indicator for immunological tolerance, linked to the activity of regulatory T cells. In conclusion, food-specific IgG 4 does not indicate (imminent) food allergy or intolerance but rather a physiological response of the immune system after exposure to food components. Therefore, testing of IgG4 to foods is considered as irrelevant for the laboratory work-up of food allergy or intolerance and should not be performed in the case of food-related complaints. © 2010 by Walter de Gruyter Berlin New York.