IgE and IgG4 subclass in atopic families.

Raised levels of IgG4 were present in twelve (35%) of thirty-four asthmatic children and raised levels of IgE in twenty-three (68%). Eighteen of 104 first degree relatives also had raised levels of IgG4, thirteen had no history of atopic disease and nine failed to give positive skin reactions to Dermatophagoides pteronyssinus or to mixed grass pollens. Fifteen relatives had raised IgE, five without symptoms. No relationship was noted between either raised levels of IgE or IgG4 and infant feeding. Although these immunoglobulin patterns were not consistently associated with symptoms they did tend to be associated in atopic families and it is suggested that the same polygenic factors may govern the IgE and IgG4 levels.