Sublingual Immunotherapy for Asthma: Affects T-Cells but Does not Impact Basophil Activation

Allergen-specific immunotherapy (SIT) is the unique modifying treatment of atopic diseases. Dysregulation of T-cell apoptosis plays a crucial role in the in the development of asthma. Nevertheless, the effect of sublingual immunotherapy (SLIT) on T-cell apoptosis has not been elucidated. The aim of the study was to evaluate the influence of 1 year of SIT in atopic children on the frequency of Th1 and Th2 cells in peripheral blood, on T-cell apoptosis, and on the response of basophils to allergen challenge. Children suffering from bronchial asthma were treated with SLIT for 12 months (Staloral 300). Basophil activation was evaluated by measurement of CD203c antigen expression. Th1 and Th2 cells frequencies and their associated frequencies of apoptosis by the expression of Bcl-2 were evaluated with flow cytometry. Basophil activation showed no difference in response before and after therapy. The frequency of Th1 cells increased (p=0.01, n=19), whereas the frequency of Th2 cells remained stable. Additionally, a significant increase of Bcl-2 positive Th1 cells was found (p=0.0465, n=19). We conclude that the increase in frequency of Th1 cells secondary to SLIT might be associated with increased resistance to apoptotic signals. The basophil activation is not useful in evaluation of patient desensitization.