Basophil sensitivity in patients not responding to venom immunotherapy

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.

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.

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).

The results suggest that basophil venom-specific sensitivity is associated with the efficiency of VIT.