薬理と治療

Abstract

Background　Daily intake of heat-killed Lactobacillus plantarum L-137（HK L-137）augmented acquired immunity and decreased incidence of upper respiratory symptoms（URS）in healthy adults under stress. However, effects of HK L-137 on URS-related cytokines are poorly understood. Therefore, we investigated the effects of HK L-137 on serum type-interferon（IFN）and incidence of URS in low immunological responders who might be susceptible to upper respiratory infection due to immunosuppression by higher stress. Methods　We reanalyzed our published data from a randomized, double-blind, placebo-controlled trials in seventy-eight healthy participants with high levels of psychological stress （mean age 50.6 y）（J Nutr Sci 2013; 2: e39）and performed a stratified analysis by using stress levels. In the study, participants took a tablet with or without 10 mg HK L-137 daily for 12 weeks, and we examined serum IFN-β concentrations and episodes of URS in low immunological responders（participants whose psychological and physical stress levels were in top two thirds at baseline）.Results　In the low immunological responders, the percent change from baseline in serum IFN-β concentrations at week 8 and at week 12 were significantly higher in the HK L-137 group than in the control group（P＜0.05）. The URS incidence and duration of medication during the study were significantly lower（P＜0.05）in the HK L-137 group than in the control group Conclusions　These results suggest that a daily intake of HK L-137 augments natural immunity in the low immunological responders, thereby improving upper respiratory conditions.（Jpn Pharmacol Ther 2022；50：1871‒80）