The cross-reactivity of IgE antibodies with pollen allergens. I. Analyses of various species of grass pollens.

Atopic patients with histories of grass pollen allergy often are sensitive to a variety of species of grasses. Using a serum pool from patients sensitive to June grass, we analyzed the reactivity of IgE antibodies to seven grasses by the radioallergosorbent test. Extracts were analyzed for their inhibitory activities with solid-phase allergens prepared from all of the grass pollen. Also samples of serum were exhaustively absorved with solid-phase allergens and the supernatants tested to determine the reactivity of the remaining IgE antibodies. Three patterns of reactivity were observed: (1) June, orchard, meadow fescue, and perennial rye grasses displayed similar reactivity in both inhibition and absorption studies; (2) sweet vernal and Bermuda grasses were considerably less reactive with the serum pool, indicating that they lacked antigenic determinants possessed by the other grasses; and (3) timothy grass possessed unique antigenic determinants. Knowledge of these patterns of cross-allergenicity is of importance for diagnosis and treatment of sensitive patients as well as for in vitro standardization of extracts.