Comparison of the Safety Profiles of 3 Different Hymenoptera Venom Immunotherapy Protocols: A Retrospective 2-Center Study of 143 Patients.

Venom immunotherapy (VIT) is highly effective and the treatment of choice for patients with a history of systemic anaphylactic reactions to a Hymenoptera sting. It has been assumed that VIT protocols with a rapid dose increase during the induction phase are associated with a higher frequency of systemic reactions (SR); however, study data addressing this issue are conflicting. The aim of this study was to compare the safety of 3 different Hymenoptera VIT protocols (half-day ultra-rush, 3-day rush, 3-week cluster). This retrospective 2-center study included 143 Hymenoptera venom-allergic patients, who underwent 147 VIT procedures during the years 2015-2018. Twenty cluster, 75 rush, and 52 ultra-rush VIT protocols were performed with honeybee (54 protocols) and wasp (93 protocols) venom. All documented side effects were classified into large local and SR (Ring and Messmer classification). SR were observed during 11 (7.5%) VIT procedures and did not exceed severity grade II. SR occurred more frequently in cluster compared to accelerated protocols. This result was observed for both honeybee (cluster: 25%, rush: 8.7%, and ultra-rush: 15.8%) and wasp VIT (cluster: 12.5%, rush: 0%, and ultra-rush: 6.1%), though the differences were statistically significant only in the wasp VIT subgroup. Honeybee venom elicited more SR than wasp venom (14.8 and 3.2%, respectively, p = 0.01). The risk for SR did not depend on age, sex, concomitant antihypertensive medication, hypertryptasemia, or severity of the index sting reaction. Accelerated VIT protocols, namely, rush and ultra-rush protocols are safe therapeutic options for Hymenoptera venom-allergic patients and displayed fewer SR than cluster VIT protocols in our study