ALLERGENIC RELATIONSHIP BETWEEN TAXONOMICALLY DIVERSE POLLENS

Background Skin tests and tests for IgE antibodies show that subjects are usually sensitive to a number of different pollens, frequently fro m taxonomically diverse species which are assumed to be allergenically non-crossreactive. This suggests that the presence of IgE antibody-re activity to an individual pollen may not necessarily have resulted fro m contact with that pollen or even with a taxonomically closely relate d species. Objective Since this has important consequences for allerge n avoidance and desensitization of patients, we attempted to define al lergenic relationships between diverse pollen species. Methods Sera fr om subjects were examined in direct IgE antibody binding experiments a nd by quantitative inhibition, protein blotting and adsorption and elu tion studies. Results Sera from subjects diagnosed as allergic to whit e cypress pine, Italian cypress, ryegrass or birch pollen were shown t o have IgE antibodies that reacted with pollens from these four specie s and from cocksfoot, couch grass, lamb's quarter, wall pellitory, oli ve, plantain and ragweed. These reactions were confirmed in protein bl otting and adsorption and elution studies where numerous IgE-binding b ands were detected in all 11 different pollen extracts with sera from each of the different allergic categories. Further evidence of allerge nic (i.e. IgE-binding crossreactivity between the different pollens wa s provided by inhibition studies in which clear-cut inhibitions of IgE binding to the different pollen allergen discs were obtained with com parable amounts of the different pollen extracts. Conclusion We conclu de that the presence of pollen reactive IgE antibodies may not necessa rily be a true reflection of sensitizing pollen species.