A reduction in allergen-induced Fc epsilon R2/CD23 expression on peripheral B cells correlates with successful hyposensitization in grass pollinosis.

BACKGROUND

The cellular basis for the mechanism of specific hyposensitization is still unclear.

OBJECTIVE

We prospectively studied the effect of immunotherapy on allergen-induced proliferation and Fc epsilon R2/CD23 expression of lymphocytes.

METHODS

Mononuclear cells prepared from the peripheral blood of 22 patients with grass pollen (GP) allergy before, during, and after a preseasonal immunotherapy period with GP were stimulated with GP or control antigens. Tritiated thymidine uptake and percentage of CD23+ B cells were determined daily during days 6 to 8 and compared with lymphocyte responsiveness of 11 only symptomatically treated atopic patients and 14 nonatopic individuals.

RESULTS

GP-induced lymphocyte proliferative response of both hyposensitized and symptomatically treated GP-allergic patients decreased markedly before the pollen season and rose again after seasonal allergen exposure, whereas a long-lived decrease in GP-induced Fc epsilon R2/CD23+ B cells was only observed in GP-treated patients. Alterations in Fc epsilon R2/CD23 expression were closely related to changes in symptoms and medication requirement during the following pollen season. In contrast, immunotherapy had no effect on Fc epsilon R2/CD23 expression of B cells without stimulation or on B cells cultured in the presence of control antigens.

CONCLUSION

Because Fc epsilon R2/CD23 expression on B cells is antagonistically regulated by the cytokines interleukin-4 and interferon-gamma, the decrease of allergen-induced Fc epsilon R2/CD23+ B cells indicates an altered cytokine secretion pattern of the allergen-specific T lymphocytes with a predominance of interferon-gamma.