Clinical Efficacy of Probiotic Bifidobacterium longum for the Treatment of Symptoms of Japanese Cedar Pollen Allergy in Subjects Evaluated in an Environmental Exposure Unit

Background: Japanese cedar pollinosis (JCPsis) affects nearly one in six Japanese. Oral administration of Bifidobacterium longum BB536 has been shown to be effective in relieving JCPsis symptoms during the pollen season. Methods: This double- two-way crossover study was designed to evaluate the efficacy of BB536 on reducing symptoms in JCPsis patients exposed to Japanese cedar pollen (JCP) in an environmental exposure unit (EeU) outside of the normal JCP season. After a 1-week run-in period, subjects (n=24) were randomly allocated to receive BB536 powder (approximately 5 x 1010) or placebo twice a day for 4 weeks. After a 2-week washout period, subjects were crossed over to another 4 weeks of intake. At the end of each intake period, subjects received controlled JCP exposure for 4 hours in the EEU. Symptoms were self-rated 30 minutes before and every 30 minutes during the exposures. From the first day of exposure through the next 5 successive days, participants self-rated their delayed symptoms and medication uses. Blood samples were taken before the exposures. The mean JCP levels for exposures were 6500 to 7000 grains/m3 air. Results: In comparison with placebo, BB536 intake significantly reduced the ocular symptom scores during JCP exposures. Evaluating delayed symptoms after exposures indicated that scores for disruption of normal activities were significantly lower in the BB536 group compared with the placebo group. Prevalence of medication use was markedly reduced by BB536 intake. Conclusions: These results suggest the potential beneficial effect of BB536 in relieving symptoms of JCP allergy