Allergy to bumblebee venom. III. Immunotherapy follow-up study (safety and efficacy) in patients with occupational bumblebee-venom anaphylaxis

Background: The objective was to investigate whether venom immunotherapy with bumblebee venom (BBV) is safe and effective. Methods: Eleven patients with severe occupational anaphylaxis caused by stings of bumblebees were studied. Sensitization to bumblebee venom was confirmed by skin tests and RAST. Immunotherapy was started with bumblebee venom extract by the semirush procedure, because these patients showed a primary sensitization to Bombus venom, and a low or absent degree of cross-reactivity with honeybee venom. IgE titer and skin tests with bumblebee venom were performed yearly. Efficacy was evaluated by means of in-hospital sting challenge and/or occupational field stings from bumblebees. Results: All patients reached maintenance dose in 6 weeks without severe side-effects. During the follow-up period (1.5-5 years), three systemic reactions in two patients were seen in 20 bumblebee stings. However, these reactions were milder than the index sting. Conclusions: Immunotherapy with bumblebee venom is safe and effective, and is comparable with honeybee and yellow-jacket venom immunotherapy.