Fluctuation of fecal microbiota in individuals with Japanese cedar pollinosis during the pollen season and influence of probiotic intake.

We have previously reported the results of a randomized, double-blind, placebo-controlled trial that found the intake of yogurt supplemented with a probiotic strain, Bifidobacterium longum BB536, alleviates symptoms and affects blood parameters in individuals with Japanese cedar pollinosis (JCPsis) during the pollen season.In the present study, fecal microbiota were investigated to examine whether any changes occur during the pollen season and whether any influence is exerted by probiotic intake.Yogurt either with BB536 (BB536 yogurt) or without BB536 (placebo yogurt) was administered for 14 weeks at 2 x 100 g per day to 40 subjects (17 men, 23 women) with a clinical history of JCPsis. Fecal samples were obtained from 23 subjects (placebo group, n=13; BB536 group, n=10) before and during the intervention (weeks 4, 9 and 13) and fecal microbiota were analyzed using terminal-restriction fragment length polymorphism and real-time polymerase chain reaction (PCR) methods.From the fluctuation patterns of terminal-restriction fragments, the Bacteroides fragilis group and bifidobacteria were among the species that changed most with pollen dispersion. Real-time PCR analyses indicated that the cell numbers of the B fragilis group increased significantly along with pollen dispersion in both BB536 and placebo groups. Cell numbers of bifidobacteria were significantly higher in the BB536 group compared with the placebo group (P < .05 at weeks 4 and 9). The ratio of cell numbers of the B fragilis group to bifidobacteria increased significantly during the pollen season in the placebo group (P < .01 at weeks 9 and 14), but not in the BB536 group. An in vitro study using peripheral blood mononuclear cells from JCPsis subjects indicated that strains of the B fragilis group induced significantly more helper T cell (T(H)) type2 cytokines (interleukin [IL]-6) but fewer T(H)1 cytokines (IL-12 and interferon) compared with those of bifidobacteria.These results suggest a relationship between fluctuation in intestinal microbiota and pollinosis allergy. Furthermore, intake of BB536 yogurt appears to exert positive ihfluences on the formation of anti-allergic microbiota.