Table 1.
Clinical studies reporting regulatory effect of probiotic bacteria on immune responses.
| Study design | Subjects | Probiotics used | Main findings |
|---|---|---|---|
| An open-label, parallel-group trial [85] | 2783 schoolchildren (6–12 years of age) | Lactobacillus brevis KB290 (KB290), 5 days per week for 8 weeks in the form of test drink containing 6 × 109 CFU | The risk of infection ↓ |
| A retrospective study [86] | 15 patients | Clostridium butyricum, three times per day at the dose of 108 CFU/tablet prior to H7N9 infection | Microbiota diversity after antibiotic cessation ↑ |
| A randomized, double-blind, placebo-controlled pilot trial [88] | 209 nursing home residents (65 years of age and older) | Lactobacillus rhamnosus GG, twice a day for 6 months in the form of capsule containing 1010 CFU | The risk of influenza infection ↓not statically significance (NS) The risk of other respiratory viral infections ↓(NS) |
| A randomized controlled, open labeled study [89] | 982 women (aged 20 or older) | Lactobacillus bulgaricus OLL1073R-1 and Streptococcus thermophiles, daily for 16 weeks in the form of yoghurt containing 109 CFU | IFN-γ production in serum ↑ |
| A randomized, double-blind, placebo-controlled trial [92] | 190 adult volunteers | Bifidobacterium animalis, daily for 33 days in the form of a sachet containing a minimum of 2 × 109 CFU | Nasal lavage viral titers ↓ virus shedding in the nasal secretions ↓ |
| A randomized, double-blind, placebo-controlled study [94] | 94 preterm infants(Aged between days 3 and 60 of life) | Lactobacillus rhamnosus GG, daily for 30 days in the form of capsule at the dose of 1 × 109/2 × 109 | Incidence of RTIs ↓ |
| The clinical and experimental randomized, double-blind, placebo-controlled, pilot study [96] | 59 healthy subjects (aged 18–65 years) | Lactobacillus rhamnosus GG, daily for 6 weeks in the form of juice containing 109 CFU | Rhinovirus infection rate ↓(NS) |
| A randomized, double-blinded, and placebo-controlled parallel group intervention study [98] | 523 children attending day care (aged 2–6 years) | Lactobacillus rhamnosus GG, daily for 25 weeks in the form of milk at the dose of 108 CFU | The number of days with respiratory symptoms ↓ |