Leukocyte phenotype changes induced by specific immunotherapy in patients with birch allergy.

ABSTRACT

BACKGROUND: The underlying mechanisms of allergen-specific immunotherapy (SIT) are not fully understood. OBJECTIVES: The present study aimed to investigate how leukocyte phenotypes are affected by SIT. METHODS: Blood samples were taken from 10 patients with birch pollen--induced allergic rhinitis before, during, and immediately after SIT. Further samples were obtained after 1 year and 3 years. All samples were analyzed by flow cytometry and leukocyte differentiation. RESULTS: SIT caused a decrease in cell-bound immunoglobulin (Ig) E on granulocytes, along with a corresponding increase in the high-affinity IgG receptor. Accordingly, a lower level of allergen-specific IgE was found after 3 years. The treatment induced a decrease in neutrophil CD1 1b levels, a shift in monocyte subsets, and an increase in the number of activated T lymphocytes, manifested as an upregulation of CD69 and CD98, and an expansion of the CD4+CD25+ T-cell pool. CONCLUSION: The present study shows that the clinical effects of SIT are mirrored by systemic changes in cellular events and in antibodies, and offers new targets for immunomodulation.