The molecular pathology of IgG4 in allergic conditions

In the time available, I have built up a picture of the molecular pathology of IgE antibodies; and considered that of IgG4 antibodies in comparison. As will have become apparent, much less direct evidence is available on the latter; partly because of lack of reliable and relevant in vitro functional assays. Nevertheless, I hope that in speculating on the possible molecular pathology of IgG4 antibodies, I have said enough to convince you that their likely mode of action in immediate-type hypersensitivity reactions will prove to be fundamentally different to that of IgE antibodies. It is important to bear this in mind in attempts to devise suitable assays of use in clinical diagnosis; and in considering their unique contributions to allergic reactions.