Heterogeneity of allergenic extracts and of the antibody response in allergic patients.

Abstract

An attempt to provide an overview of intrinsic problems encountered in the definition of the immunochemical parameters involved in the allergic response in terms of the appropriate in vivo and in vitro manifestations. The primary difficulty stems from the complexity of the chemical composition of most extracts of allergenic materials and from the lack of simple laboratory methods for establishing the allergenic profile of each patient as a function of the different components of a given extract. The principles of inhibition of the Prausnitz-Küstner passive transfer test and of the radioallergosorbent technique will be described; from the results one may deduce the minimum number of distinct allergenic components and of the corresponding reaginic antibodies of IgE type. The possible use of monovalent, hapten-like, low molecular weight constituents of allergens for blocking the triggering of the release of vasoactive amines from mast cells and basophils of allergic patients will be discussed. In addition of IgE antibodies, the spectrum of antibodies produced by the allergic patient, both before and after hyposensitization, involves immunoglobulins of the IgG, IgM and IgA classes, which can be measured by radioimmunoelectrophoretic and -immunodiffusion techniques; IgM antibodies can be readily differentiated from IgG antibodies by the hemagglutination technique, or by adaptation of reverse immunosorbent procedures. Similarly, the heterogeneity in relative affinities of the different antibodies for a given allergenic fraction may be established by the use of immunosorbents. The effectiveness of hyposensitization therapy could be thus correlated with objectively measurable immunological parameters. Possible mechanisms responsible for the effectiveness of this treatment will be discussed in the light of recent experiments in animal systems, suggesting the mandatory cooperation between T and B cells for the induction of the reaginic response.