Clustered immunotherapy with Yellow Jacket venom. Evaluation of the influence of time interval on in vivo and in vitro parameters.

To evaluate difference in clinical efficacy, side effects, in vivo and in vitro parameters, 25 patients allergic to Yellow Jacket were treated with clustered immunotherapy using either 7 or 14 days interval between clusters. Twenty-one patients completed the 6 months' treatment period and four were withdrawn due to adverse reactions (2 cases of anaphylactic shock). Sixteen patients were challenged by in-hospital sting and the clinical efficacy was complete. Local side effects were observed in the majority of patients, but only rarely limited the course of immunotherapy. Skin sensitivity estimated as the venom concentration eliciting a wheal equal to histamine HCl 0.1 mg/ml using intradermal test was significantly reduced after 6 months of treatment. Specific IgE showed an initial increase, thereafter declining to pretreatment levels. IgG subclasses were determined by a triple antibody assay. Only subclasses 1 and 4 showed response. Subclass 4 showed a steady increase contrary to subclass 1 which decreased after reaching maintenance dose. No unambiguous relation between either the absolute value or the change of IgG1 and IgG4 at the time of challenge was observed in the patients who tolerated a sting. Furthermore, the IgG response was not correlated to the cumulative dose of venom administered. No simple regulatory function of IgG subclasses in the skin and IgE response was found, and the occurrence of local side effects did not seem to be determined by IgG antibodies. We conclude that clustered immunotherapy with Yellow Jacket venom is highly effective and that the frequency of side effects is acceptable.(ABSTRACT TRUNCATED AT 250 WORDS)