Abstract
The role of IgG4 antibodies in immediate hypersensitivity will be discussed in this paper, both from experimental and clinical point of view. The data described will show that 1) not only IgE but also IgG4 molecules are present on human basophils, 2) IgE-mediated basophil degranulation may be inhibited by passive sensitization with excess amounts of IgG4 antibodies, 3) allergen-specific IgG4 antibodies become prominent upon repeated parenteral stimulation with antigen, such as immunotherapy and bee-stings, in asthmatics and in bee keepers. The overall results suggest that IgG4 antibodies may react as blocking antibodies which produce protective effect during clinical course, in a certain type of allergic disorders. The role of IgG4 antibodies as anaphylactic antibodies will be also briefly discussed.
