Evolution of the Identification of Allergen-Specific IgE

In the late 1960s, IgE was isolated and characterized and found to have “reaginic” activity. The term reagin was used to identify the immunologic mediator of immediate hypersensitivity reactions. Reaginic antibodies were detected by the Prausnitz-Küstner (PK) reaction. This test was performed by passively sensitizing the skin of a nonallergic recipient with an intradermal injection of serum of an allergic person and challenging the test site 24 to 48 hours later with an injection of an allergen extract. An immediate wheal and flare reaction indicated a positive test. Before IgE was identified, IgA was thought to be the carrier of reaginic activity.The experiments described in this abstract were done after ragweed-specific IgE had been identified. The purpose was to determine whether reaginic antibodies reacting with other allergens were also IgE. The results indicated that a wide variety of allergic models—pollen, dust, food, insects, and drugs—were also mediated by allergen-specific IgE.Over the past 40 years, very refined techniques have evolved for detection and quantitation of allergen-specific IgE. It is the well documented mediator of immediate hypersensitivity reactions. Immune modifiers (omalizumab) have been developed and can decrease serum levels of allergen-specific IgE, providing clinical benefit.In retrospect, the data described in the abstract 40 years ago were the forerunners of the now well-recognized clinical significance of allergen-specific IgE. In the late 1960s, IgE was isolated and characterized and found to have “reaginic” activity. The term reagin was used to identify the immunologic mediator of immediate hypersensitivity reactions. Reaginic antibodies were detected by the Prausnitz-Küstner (PK) reaction. This test was performed by passively sensitizing the skin of a nonallergic recipient with an intradermal injection of serum of an allergic person and challenging the test site 24 to 48 hours later with an injection of an allergen extract. An immediate wheal and flare reaction indicated a positive test. Before IgE was identified, IgA was thought to be the carrier of reaginic activity. The experiments described in this abstract were done after ragweed-specific IgE had been identified. The purpose was to determine whether reaginic antibodies reacting with other allergens were also IgE. The results indicated that a wide variety of allergic models—pollen, dust, food, insects, and drugs—were also mediated by allergen-specific IgE. Over the past 40 years, very refined techniques have evolved for detection and quantitation of allergen-specific IgE. It is the well documented mediator of immediate hypersensitivity reactions. Immune modifiers (omalizumab) have been developed and can decrease serum levels of allergen-specific IgE, providing clinical benefit. In retrospect, the data described in the abstract 40 years ago were the forerunners of the now well-recognized clinical significance of allergen-specific IgE.