Impact of Naturally Composed and Size-Excluded Hymenoptera Venom Preparations on the Safety and Efficacy of Venom Immunotherapy: A Monocentric Experience.

Introduction: The first-line treatment for patients with Hymenoptera venom allergy, a potentially life-threatening condition, is venom immunotherapy (VIT). However, for reasons still unclear, honeybee VIT (HBV-IT) is less effective than yellow jacket VIT (YJV-IT).

Methods: This retrospective monocentric study aimed to investigate the safety and efficacy of naturally composed Hymenoptera venom (NC-HV) in a rush protocol involving a high total venom dose and to compare the results with those previously obtained using size-excluded Hymenoptera venom (SE-HV). Data regarding the number of build-up cycles and maintenance of VIT with NC-HV were retrieved from institutional records. The VIT protection rate was determined by the results of the sting challenge test (SCT).

Results: We evaluated 648 individuals treated with NC-HV and compared their results with data from 1,258 individuals treated with SE-HV. The frequency of systemic reactions (SRs) with NC-HV in HBV-IT was 25.6%, and that with YJV-IT was 10.1%. Compared with previous experience with SE-HV, the use of NC-HV was associated with an increased frequency of SRs (SR rates of HBV-IT 10.4 and YJV-IT 6.3%). The protection rate in HBV-IT, as determined by SCT, was 100% with NC-HV, which is notably higher than the 95.4% previously reported with SE-HV. The efficacy of YJV-IT was equivalent to 99.0% for NC-HV and 99.6% for SE-HV.

Conclusion: Nearly complete protection was achieved with the NC-HV. The efficacy gap between HBV-IT and YJV-IT, which has limited VIT for decades, can be overcome with NC-HV in combination with a high total venom dose rush protocol.