Suplatast tosilate affects the initial increase in specific IgE and interleukin-4 during immunotherapy for perennial allergic rhinitis.

Suplatast tosilate can inhibit IL-4 production and suppress IgE synthesis in vitro. However, the theory that the agent causes changes in production of IL-4 and IgE in vivo has little experimental support. Immunotherapy could decrease the specific IgE response, but such a favourable effect is only possible with prolonged therapy after an initial increase in specific IgE. The use of suplatast tosilate together with immunotherapy may blunt the initial rise in specific IgE and decrease serum levels of specific IgE more quickly. Eighty-three adult patients with perennial allergic rhinitis due to Dermatophagoides farinae (D. farinae) were treated for 6 months with one of 3 treatments. Seventeen patients were treated with oral administration of 300 mg/day suplatast tosilate alone. Forty-six patients were treated with immunotherapy using standardized D. farinae alone. Twenty patients were treated with immunotherapy together with concurrent oral administration of 300 mg/day suplatast tosilate. Serum samples were collected 3 times from each patient, at enrollment, at 3 months and at 6 months after enrollment. Oral administration of suplatast tosilate for 3 and 6 months significantly decreased serum levels of IL-4 and specific IgE, and the rate of decrease in specific IgE correlated significantly with the rate of decrease in IL-4. The rates of decrease in IL-4 and specific IgE at 3 and 6 months were significantly greater in the patients treated with suplatast tosilate and immunotherapy than in those treated with immunotherapy alone. In conclusion, suplatast tosilate is able significantly to decrease serum levels of IL-4 and specific IgE, and the use of the drug together with immunotherapy can blunt the initial increase in specific IgE during the first 6 months of immunotherapy.