Background: Little is known whether sublingual immunotherapy using Japanese cedar pollen extract (cedar SLIT) is effective for not only Japanese cedar pollinosis but also Japanese cypress pollinosis. We investigated the prevalence rate of Japanese cypress pollinosis, efficacy of cedar SLIT on cypress pollinosis and patients' wish to receive cypress SLIT.
Methods: We investigated a multi-center (31 institutions), cross-sectional survey using a self-administrated questionnaire with four questions for patients received cedar SLIT aged from 5 to 69 years old.
Results: 2523 subjects were enrolled for analysis. 83.4% of them had pollinosis symptoms during cypress season before cedar SLIT. In such patients, 37.4% experienced lessened efficacy of cedar SLIT during cypress season. Both the prevalence of cypress pollinosis and the lessened efficacy of cedar SLIT on cypress pollinosis were significantly seen in western Japan as compared to eastern Japan. 76.1% of the subject having cypress pollinosis before SLIT wished to receive cypress SLIT if it is available.
Conclusion: A lessened efficacy of cedar SLIT during cypress season was broadly seen in Japan, and further showed a regional difference. Together with the finding of high wish by patients, these results suggest a development of cypress SLIT is desirable.
Keywords: Japanese cedar pollinosis; Japanese cypress pollinosis; allergen component; questionnaire; sublingual immunotherapy.