Background: We investigated the effect of sublingual immunotherapy (SLIT) on Japanese cedar and cypress pollinosis in a mass scattering year of cedar pollen (total counts: 12353 grains/cm2, approximately four times the average).
Methods: SLIT patients of 84 in the first year, 107 in the second year and 67 in the third year treated with Cedarcure® were included. During the 2023 cedar and cypress pollen dispersal season, nasal and eye symptoms and general symptoms were examined using a visual analog scale (VAS).
Results: The VAS during the cedar season significantly decreased to improve with the number of years of SLIT, but the VAS during the cypress period slightly increased. A questionnaire survey before SLIT revealed that only 0.9% to 3.6% of patients had strong cypress symptoms. However, sneezing (p＜0.01), rhinorrhea, itchy eyes and total symptoms (p＜0.05) in the third year of SLIT were significantly stronger during the cypress period than during the cedar period. The VAS of total symptoms during the Japanese cedar pollen season were not affected by the pollen count, and the cure rate was affected by SLIT in the third year.
Conclusion: The clinical efficacy of cedar SLIT on cedar pollinosis was high even in a mass scattering year, and the effect increased with the number of years of treatment. On the other hand, it was shown that the clinical efficacy on cypress pollinosis was insufficient.
Keywords: Cedarcure®; cedar pollen; clinical efficacy; cypress pollen; sublingual immunotherapy.