Sublingual immunotherapy for Japanese cedar pollinosis: potential biomarkers predicting therapeutic responses

Abstract

Objective: Sublingual immunotherapy (SLIT) for allergic rhinitis due to Japanese cedar ( JC) pollisosis was investigated to examine its clinical efficacy and adverse effects, as well as the changes of serum antibodies.Research design and methods: A placebo-controlled, double-blind study was performed with 12 patients in the SLIT group and 16 patients in the placebo group. Treatment was started before the JC pollen season and was continued until after the pollen season. The SLIT group received daily up-titration of a JC pollen allergen extract over 2 weeks, followed by maintenance therapy twice weekly. The placebo group received the vehicle of the allergen extract at the same dosage. Subjects kept symptom diaries during the JC pollen season.Main outcome measures: Scores were assigned for nasal symptoms (sneezing, itching, rhinorrhea, and obstruction) and the total nasal symptom score (TNSS) was calculated during the pollen season. Immunoglobulin levels were measured before and after treatment.Results: During the 90-day period from February 1 to April 30, the sneezing score, nasal itching score, rhinorrhea score, nasal congestion score, and TNSS were significantly lower in the SLIT group than the placebo group for 15, 15, 33, 22, and 37 days, respectively. Serum levels of JC allergen-specific IgG and IgE showed no significant difference between the 2 groups before treatment, but were significantly higher in the SLIT group than the placebo group after the pollen season. Although JC allergen-specific IgG4 was also higher in the SLIT group after the pollen season, there was no significant difference. The IgG4/IgG ratio showed no significant difference between the two groups either before treatment or after the pollen season. Adverse events were only Grade 1 in both groups and resolved spontaneously.Conclusions: SLIT suppressed symptoms of JC pollinosis and increased the JC-specific IgG4/IgG ratio in the first season of treatment.