Background: The efficacy of specific immunotherapy has been verified. There is accumulating evidence focusing on the T lymphocyte-eosinophil interaction in the pathogenesis of asthma. The aim of this study was to clarify whether immunotherapy affects the production of eosinophil chemotactic activity (ECA) from peripheral blood mononuclear cells (PBMC).
Methods: PBMC obtained from persons with bronchial asthma who were sensitive to Dermatophagoides farinae (Df) or from healthy volunteers were cultured for 96 hours in the presence or absence of Df. ECA in culture supernatants was assayed by means of the modified Boyden's chamber method.
Results: There was no significant difference in the baseline levels of ECA between asthmatic persons treated with immunotherapy and those without immunotherapy. The addition of Df (10 to 10(4) ng/ml) enhanced the ECA production in a dose-dependent fashion in asthmatic persons without immunotherapy, and there was a statistically significant correlation between the concentrations of Df and the levels of ECA (rk = 0.34; p < 0.05). In contrast, Df-dependent ECA production was suppressed in asthmatic persons with immunotherapy, and the suppressive effect was observed from 4 weeks after rush immunotherapy.
Conclusions: These results indicate that immunotherapy induces the suppression of antigen-dependent production of ECA from PBMC. This may contribute to the attenuation of eosinophil infiltration into the airways in asthma patients.