The effect of silk peptide on immune system, A randomized, double-blind, placebo-controlled clinical trial

In this study, we evaluated the immunostimulatory effect of silk peptide in subjects with peripheral blood leukocyte levels of 4–8 × 10 ³ /μl by a randomized, double-blind, placebo-controlled clinical trial. The subjects were randomly assigned to one of two groups, the placebo control or silk peptide intervention group, for 8 weeks. As a result, evaluation of efficacy in 97 subjects showed no significant difference between the groups in immunostimulatory parameters. However, after separate analysis of 61 non-season influenza vaccine subjects, the natural killer cell activity (%) with an effector cell: target cell (E: T) ratio of 10:1 was increased significantly from 30.7 ± 2.28% at week 0 to 41.8 ± 2.71% at week 8 (p < 0.01) in the silk peptide groups. In addition, IL-2, IL-12, and IFN-γ levels were increased in the silk peptide group and decreased in the placebo group. These results suggested that silk peptide is effective for enhancing immune activity.