91 Efficacy of Venom Immunotherapy Given Every 3 or 4 Months. A Direct Prospective Comparison With the Conventional Regimen

relationship to proportion of regulatory T cells. Methods: Forty-five patients with history of systemic symptoms of allergy to Hymenoptera venom were included. Basophil reactivity before the treatment and after one year of allergen immunotherapy (AIT) was measured by CD63 expression, CD203c marker used for basophil identification. Cells were stimulated by aqueous solution of allergen in concentration range 0.01 to 1 mg/mL. T regulatory cells were identified as CD4 positive, CD25 bright and CD127 negative at the same interval of treatment. Monoclonal antibodies conjugated with fluorochromes were used, measured by FACSCalibur. Paired t test and correlation analysis used for statistical evaluation. Results: Median Treg proportion before therapy was 2.160, after IT 1.960, basophil specific response (proportion of CD63 positive cells) at the same interval were 3.65 and 4.11 at 0.01 mg/mL, 13.1 and 16.1 for 0.1 mg/mL and 33.85 and 40.8 for 1 mg/mL. All differences were not statistically significant. Differences of basophil activation were not significantly related to proportion of T regulatory cells. Conclusions: In our group of patients with HV allergy, treated by AIT, we did not found any relationship between basophil specific activation during allergen immunotherapy and proportion of T regulatory cells.