[Determination of specific IgG4 in allergy]

Measurement of the titre of specific IgG4 by the ELISA method may provide objective assistance to the control of specific immunotherapy (IS) to hymenoptera venom and grass pollens. A marked increase of the specific IgG4 titre in the first 3 months of IS or a titre already raised before the start of IS correlated with poor clinical results. Specific IgG4 can not be considered to be a diagnostic indicator in food allergy since we have frequently found this type of antibody in control subjects. Specific IgG4 in food allergy expresses a mucosal marker rather than a pathological reaction.