Immuun eiwitten in bloed zinloos bij MS
Serological tests for immunoglobulin G4 (IgG4) against foods are persistently promoted for the diagnosis of food-induced hypersensitivity. Since 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 IgG4 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 IgG4 does not indicate (imminent) food allergy or intolerance, but rather a physiological response of the immune system after exposition 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 case of food-related complaints. 
Testen van IgG lijkt dus niet zinvol
Dat is duidelijke taal. Er komen in het bloed wel IgG stoffen voor, maar dat wil alleen zeggen dat je dat voedsel hebt gegeten. Er is geen enkel bewijs dat er een ziekte kan ontstaan door de aanwezigheid van deze normaal voorkomende antistoffen in het bloed!
 Stapel SO, Asero R, Ballmer-Weber BK, Knol EF, Strobel S, Vieths S, Kleine-Tebbe J; EAACI Task Force. | Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report. | Allergy. | 2008 Jul;63(7):793-6. doi: 10.1111/j.1398-9995.2008.01705.x. Epub 2008 May 16.