Clinical Efficacy of Halophilic Lactic Acid Bacterium Tetragenococcus halophilus Th221 from Soy Sauce Moromi for Perennial Allergic Rhinitis

Background: Recently, some common foods in daily life, especially lactic acid bacteria, have been found to have anti-allergic effects. We previously isolated a halophilic lactic acid bacterium, Tetragenococcus halophilus Th221, from soy sauce moromi, a mixture of koji and salt solution, and showed that it possesses an immunomodulatory activity that promotes T helper type 1 immunity. Methods: To evaluate the anti-allergic effects of Th221, we performed a randomized, double-blind, placebo-controlled study in 45 subjects with perennial allergic rhinitis (PAR) treated by oral administration of Th221 (high dose, 60 mg/day, 15 subjects; low dose, 20.4 mg/day, 15 subjects) or a placebo (15 subjects) for 8 weeks. Results: There were no significant differences among the groups that ingested Th221 and the placebo group regarding the disease severities, total nasal symptom scores and total nasal sign scores examined by physicians. However, the disease severity examined by physicians significantly improved in the high-dose group at the end of the trial compared with the beginning (p < 0.05). The total score for nasal symptoms of subjects who received a high dose of Th221 also showed a significant improvement at the end of the trial compared with the beginning (p < 0.01). According to the subjects’ diaries, significant improvements in sneezing and rhinorrhea were observed during some periods in the high-dose group. The change in serum total immunoglobulin E improved significantly at the end of the trial compared with the beginning in this group (p < 0.05). The safety of Th221 treatment was confirmed by laboratory tests and inspection of the general condition of each subject. Conclusions: Th221 can be expected to safely improve the symptoms of PAR.