- D1.520 - Immunological modulation during Apis mellifera venom immunotherapy
Background
Venom immunotherapy with Apis mellifera (VIT) is the most effective treatment for preventing systemic reactions after subsequent stings. The aim of this study was to evaluate the development of new molecular sensitizations during VIT and to analyze the relationship between the evolution of specific IgE and IgG4 levels and clinical tolerance to subsequent stings.
Method
A retrospective observational study was conducted at Hospital Universitario Virgen Macarena including 30 patients with a history of systemic reactions to Apis mellifera stings undergoing venom immunotherapy (VIT). Serum specific IgE and IgG4 levels to whole venom extract and molecular components (Api m 1, Api m 2, Api m 3, Api m 5, and Api m 10) were analyzed at baseline (T0) and at a follow-up time point selected for analysis within a 24–36-month time window (T1).
Results
Two new molecular sensitizations were observed (2/30; 6.7%), both to Api m 5, corresponding to the only patients who showed increases in specific IgE above the analytical positivity threshold (≥ 0.10 UIa/mL). No clinical impact was observed in these patients during immunotherapy or after subsequent stings. The remaining 93.3% of patients showed a decrease in specific IgE, both to whole venom extract and to major components (Api m 1, Api m 3, Api m 5, and Api m 10). A global net increase in IgG4 after immunotherapy was observed in 76.6% of patients.Regarding clinical outcomes, 10 patients (33.3%) underwent controlled sting challenges, with a tolerance rate of 90%. The remaining 20 patients experienced spontaneous stings, all of which were tolerated.
Conclusion
In line with previous literature, VIT with Apis mellifera in our population induces robust immunological modulation, characterized by a predominant reduction in specific IgE and an increase in IgG4, with a low frequency of new molecular sensitizations. These changes are associated with a high degree of clinical tolerance to subsequent stings, supporting the long-term effectiveness and safety of VIT.
