Anti-IgE autoantibodies and bee-sting allergy.

Serum anti-IgE autoantibodies (aaIgE) were investigated by dot immunobinding assay in bee-allergic patients in comparison with nonallergic beekeepers, healthy blood donors, and atopic subjects. Elevated serum levels of aaIgE--either free or combined with IgE--were found in both bee-allergic patients and atopic subjects as compared with beekeepers and healthy donors. With regard to a possible significance of aaIgE for the protective mechanism induced by specific allergen immunotherapy, we estimated aaIgE in bee-allergic patients before, during, and after bee-venom immunotherapy (BVIT) in relation to the outcome of a provocation test with a living bee (PT). During the first year of BVIT, there was no significant change in either free or combined aaIgE, but aaIgE decreased during protracted BVIT over 3-7 years. By using two monoclonal anti-IgE antibodies with different epitope specificity (Le27 and BSW17), we were able to detect two kinds of IgE/aaIgE immune complexes. Our data show that during and after BVIT the levels of one kind of IgE-aaIgE immune complex (the non-BSW17 type) tended to decrease in PT-negative patients but stayed elevated in PT-positive patients. The levels of the other kind of immune complex (the non-Le27 type) were similar in treatment failures and successfully treated patients. These data suggest that there are various kinds of aaIgE with different in vivo functions related to their epitope specificity. Some of them (non-BSW17 type) might be associated with BVIT failure.