Evaluation of receptor expression on immune system cells in the peripheral blood of asthmatic children undergoing food challenges.
BACKGROUND
The role of food allergens in the induction of allergic reactions in the airways is not completely understood. The aim of the present study was to evaluate fluorocytometric assays of the peripheral blood during food challenge tests in children with asthma and food allergy.


PATIENTS AND METHODS
22 children with asthma and concomitant food allergy and 18 children with asthma without food allergy participated in the study. Oral challenge tests were performed using double-blind, placebo-controlled food challenge. Blood samples were collected before and 4 and 24 h after the challenge. CD25 and CD23 antigen expression was determined with monoclonal antibodies using a FACSCalibur flow.


RESULTS
The evaluation of the CD25+ T subpopulation and CD19+CD23+ B lymphocytes revealed statistically significant differences between the study group and the control group. In children with asthma and food allergy, the cell pool consisted (on average) of 9 +/- 2.8% of CD3+CD25+ cells before the challenge and of 10.3 +/- 3.8% (mean delta: 1.623; p = 0.01) after the provocation. However, placebo challenge did not significantly change the number of this T-lymphocyte subpopulation (mean delta: -0.121; p > 0.05). The highest increase in the CD25+ T-subpopulation expression was found in patients with respiratory reactions during the positive food challenge (mean delta: 4.065; p < 0.004).


CONCLUSIONS
An increase in CD25+ T-lymphocyte and CD23 B-lymphocyte populations after food allergen challenge may indicate their significant role in the pathogenesis of the active phase of the immunoinflammatory process in children with asthma and concomitant food allergy.