Japanese cedar sublingual immunotherapy

Japanese cedar sublingual immunotherapy (SLIT) is a targeted allergen-specific immunotherapy used to treat Japanese cedar pollinosis, a widespread seasonal allergic rhinitis in Japan caused by pollen from *Cryptomeria japonica*. The therapy involves the regular administration of standardized extracts of Japanese cedar pollen under the tongue to induce immunological tolerance. Its mechanism of action centers on modulating the immune response to primary allergens, such as Cry j 1 and Cry j 2, by shifting the T-cell balance from a pro-allergic Th2 profile toward a Th1 profile and stimulating the induction of regulatory T cells (Tregs). These Tregs release inhibitory cytokines like IL-10 and TGF-β, which suppress allergic inflammation, reduce allergen-specific IgE production, and promote the synthesis of protective IgG4 and IgA antibodies. In Japan, the therapy is primarily available as Cedartolen (liquid drops) and Cedarcure (sublingual tablets), both developed by Torii Pharmaceutical. Clinical research, such as the PLUS trial, continues to evaluate optimized dosing regimens, including preseasonal re-administration, to maintain symptom control in pediatric and adolescent populations.

Brand names

CedarcureCedartolen

Other names

Japanese cedar pollen allergen extractJapanese cedar SLITCryptomeria japonica pollen extract