Role of IgG4 subclass in childhood allergy.

In 38 asthmatic patients (34 children and 4 adults) raised serum concentrations of IgE and the IgG4 subclass were found to correlate with the clinical picture. 5 children with eczema, asthma, and hayfever had grossly increased concentrations of both immunoglobulins, as did 4 adults who had had atopic eczema as children. Raised concentrations of just one of the immunoglobulin classes (i.e., IgE or IgG4) did not seem to be associated with atopic eczema. 75% of the asthmatic children in whom serum-IgG4 was raised had not shown a satisfactory response to disodium cromoglycate and required steroids to control their asthma; but 82% of patients in whom only IgE was raised responded satisfactorily to disodium cromoglycate.