A Double-blind Trial of Lactobacillus paracasei Strain KW3110 Administration for Immunomodulation in Patients with Pollen Allergy

Lactobacillus paracasei strain KW3110 has been shown by in vitro cytokine secretion analysis to be a potent Th1 inducer and Th2 repressor. Oral administration of L. paracasei strain KW3110 also represses IgE elevation in the ovalbumin sensitized mouse allergy model. During pollen season from January to April in 2003, a daily dose of 4x1010 cfu L. paracasei strain KW3110 was fed for 12 weeks as a yogurt to 14 pollen allergy patients(mean age 39.0 years). A yogurt made with Lactobacillus delbrueckii strain B, shown to be a poor Th1 inducer and Th2 repressor in a former study, was also fed at a daily dose of 4x1010 cfu for 12 weeks to 14 pollen allergy patients(mean age, 39.0 years). Blood samples were collected every 4 weeks. Eosinophils, eosinophil cationic protein(ECP), non-specific serum IgE, cedar pollen specific serum IgE, and Th1/Th2 ratios were quantified. Twelve weeks after ingestion of the yogurts, the group that was fed L. delbrueckii group showed significant reductions in the Th1/Th2 ratios between the first observation in January and last observation in April, representing the four month study period, due to increases in Th2 cells. Significant increases in ECP were also observed in the group fed L. delbrueckii between January and April. In contrast, the group fed L. paracasei had no significant changes in the ECP and Th1/Th2 ratios. Our results suggest that ingestion of the L. paracasei strain KW3110 is associated with both repression of Th2 cell generation and eosinophil activation. Our data point to the possibility that specific lactic acid bacteria may be useful for allergy therapy.