抄録
This study was designed to investigate whether prophylactic immunotherapy for individuals sensitized to Japanese cedar pollen could prevent an outbreak of pollen-induced allergic rhinitis. A total of 13 non-atopic volunteers and 67 patients sensitized to Dermatophagoides farinae (D. farinae) and Japanese cedar pollen were enrolled in the study. Before enrollment in the study, all of the 67 patients had perennial nasal symptoms due to D. farinae, but no seasonal aggravation of nasal symptoms. 32 patients were treated with immunotherapy using standardized D. farinae extracts alone (control group), and the remaining 35 patients were treated with immunotherapy using the same D. farinae extracts and Japanese cedar pollen extracts (immunotherapy group). The following results were derived from the study:
1. Prophylactic immunotherapy significantly decreased incidences of the outbreak of seasonal allergic rhinitis due to pollen.
2. IL-4 synthesis during the pollen season by peripheral blood T cells stimulated with the cedar pollen allergen were enhanced in the control group, whereas IL-4 synthesis during the season was not enhanced in the immunotherapy group. In particular, IL-4 synthesis during the season did not differ between the non-atopic volunteers and the patients who were treated with prophylactic immunotherapy for more than 3 years.
In conclusion, prophylactic immunotherapy could prevent the outbreak of seasonal allergic rhinitis in those who had been sensitized to the pollen. Therefore, it is likely that prophylactic immunotherapy is a new method of decreasing the incidence of seasonal allergic rhinitis in Japan.
