Serum samples from 31 patients sensitive to both ragweed and rye grass were quantitated for IgE specific for ragweed antigen E (AgE) and rye grass group I (rye I) antigens employing the previously described radioallergosorbent test (RAST) elution technique. IgE anti-AgE ranged from 0.4 to 320 ng/ml and comprised 0.4% to 14.2% of total serum IgE. The same sera contained IgE anti-rye I ranging from 7.9 to 1,168 ng/ml, comprising 1.6% to 29.6% of total serum IgE. A new theoretical parameter (RF), representing the percent of total IgE-Fc receptors of target cells occupied by allergen-specific IgE, was calculated for each IgE specificity by using the determinations of allergen-specific IgE antibody, total serum IgE, and assuming an equilibrium constant for binding of IgE molecules to basophils of 109M-1. This "% occupancy" parameter correlated with skin test titration, basophil cell sensitivity, and hay fever symptom scores as well as, but not better than, the absolute values of allergen-specific IgE. This finding suggests that in most atopic patients, the quantity of irrelevant IgE plays a relatively minor role in determining allergic sensitivity to a given allergen. The implications of this finding are discussed.
ASJC Scopus subject areas
- Immunology and Allergy