Improvements in seasonal allergic disease with Lactobacillus plantarum No. 14

We conducted two randomized, placebo-controlled, double-blind studies of Lactobacillus plantarum No. 14 (LP14) in female students with seasonal allergic diseases. We also examined the mitogenic activity and cytokine inducibility of LP14 using Peyer's patch cells and mesenteric lymph node cells of swine. For subjects who took 8.7×10(8) of LP14, a significant improvement in ocular symptom-medication score was observed. In the placebo group, the T helper type 1 (Th1)/T helper type 2 (Th2) ratio tended to decrease after a 6-week intake period, while in the LP14 group, the percentage of Th1 cells significantly increased. Post-intake eosinophil counts significantly increased in comparison to those at intake cessation in the placebo group, but it appeared to be suppressed in the LP14 group. There were no changes in fecal microflora. LP14 strongly induced the gene expression of Th1-type cytokines. This study indicates the clinical effects of LP14 on seasonal allergic diseases.