Purpose of the Study. Live Lactobacillus paracasei 33 (LP33) may effectively improve the quality of life for patients with perennial allergic rhinitis. It has been demonstrated that heat-killed lactic acid bacteria suppress specific immunoglobulin E synthesis and stimulate interleukin-12 production in animals. The aim of this study, therefore, was to evaluate the efficacy of heat-killed LP33 in the treatment of allergic rhinitis induced by house-dust mite in human subjects.
Study Population. A total of 90 patients older than 5 years with perennial allergic rhinitis characterized by intermittent or continuous nasal symptoms for >1 year were enrolled in a randomized, double-blind, placebo-controlled trial and assigned to 3 treatment groups.
Methods. Patients in groups A and B received 2 capsules per day of live or heat-killed lactic acid bacteria (5 × 109 colony-forming units per capsule), respectively, over a period of 30 days, whereas those in group C received placebo capsules. A modified questionnaire on pediatric rhinoconjunctivitis-related quality of life was administered to all subjects or their parents during each clinical visit.
Results. The overall quality-of-life score decreased for groups A and B compared with the placebo group in terms of both frequency (9.47 ± 2.89, 6.30 ± 2.19, and −3.47 ± 1.53, respectively; P < .0001) and level of bother (5.91 ± 3.21, 6.04 ± 2.44, and −2.80 ± 1.64, respectively; P = .004) after the 30-day treatment. The efficacy of the heat-killed LP33 was not inferior to the live variant. No obvious adverse effects were reported for either active-treatment group during the study period.
Conclusions. The results suggest that heat-killed LP33 can effectively improve the overall quality of life for patients with allergic rhinitis and that it may be efficacious as an alternative treatment.
Reviewer Comments. The hygiene hypothesis suggests that lack of early exposure to microorganisms is a factor in the recent rise in allergic disorders. Studies have shown the certain gut flora, including Lactobacillus, may have immunomodulatory effects that may be beneficial in regulating allergic responses. Concerns over safety of administering live bacteria as a therapeutic agent led Peng and Hsu to investigate the effectiveness of heat-killed lactobacillus in the treatment of allergic rhinitis. The authors demonstrate that the heat-killed version is effective in improving the quality of life of patients suffering from allergic rhinitis.
- Copyright © 2006 by the American Academy of Pediatrics