Basophil Sensitivity in Patients Not Responding to Venom Immunotherapy

BACKGROUND: Treatment failure of venom immunotherapy (VIT) is not rare and the risk and pathogenic factors for those failures are so far poorly understood. For that reason we evaluated allergen-specific basophil sensitivity in patients who did not tolerate field re-stings after completed VIT treatment. METHODS: Basophil responsiveness was evaluated by flow cytometry analyses of basophil CD63 surface expression induced by different concentrations of bee or wasp venom (1, 0.1 and 0.01 microg/ml) in 14 treated patients who had experienced systemic allergic reactions (Muller grades II-III) and 17 treated patients who had no reactions after the field re-stings. We also included a group of 28 Hymenoptera venom-allergic patients who had not received VIT. RESULTS: In 14 patients who still reacted to bee or wasp sting, basophil response at a venom concentration of 0.1 microg/ml was significantly higher than in patients who tolerated field re-stings (p = 0.03; t test). Basophil response was also slightly higher at a concentration of 1 microg/ml, but not to statistical significance (p = 0.12; t test). There was no difference in the response to direct cross-linking of the IgE and in venom-specific IgE and IgG4 serum concentrations between those 2 groups (p > 0.8; Fisher's exact test, t test). Patients who tolerated field re-stings have also significantly lower basophil response in comparison to patients who had not received VIT, both at 0.1 and 1 microg/ml of venom concentrations (p < 0.001; t test). CONCLUSIONS: The results suggest that basophil venom-specific sensitivity is associated with the efficiency of VIT.