Valerio Pravettoni, Cristoforo Incorvaia, Marta Piantanida and Erminia Ridolo
Patients with systemic reactions (SR) to Hymenoptera stings are successfully treated by venom immunotherapy (VIT), but there is not yet a general agreement on the criteria for stopping VIT. We discuss the importance of the venom-specific IgE levels among these criteria. In particular, the results from a recent study evaluating the IgE changes during a 5-year VIT, in patients stung and protected within the first 3 years (SP 0-3) or in the last 2 years (SP 3-5), and in patients not stung (NS) are considered. A total of 232 yellow jacket venom (YJV) allergic patients were included and divided into the following groups: 84 NS, 72 SP 0-3 and 76 SP 3-5. IgE levels decreased during VIT compared to baseline values (χ2=346.029, p<0.001). Recent vespid stings accounted for significantly higher IgE levels despite clinical protection. IgE levels after 5 years of VIT correlated significantly with Mueller grade (F=2.778, p=0.012) and age (F=6.672, p=0.002). More than one third of the contacted patients had at least one tolerated sting during a prolonged follow-up (up to 10 years) after stopping VIT. The stopping criterion of a duration of 5 years resulted in a decrease of IgE levels ranging from 58% to 70%, but no negative level was detected. This confirms the adequacy of the temporal criterion compared to the immunological criterion of developing negative IgE tests to decide for stopping VIT for vespid venom.