title: Daily intake of Lactobacillus casei Shirota increases natural killer cell activity in smokers.
abstract: Dietary probiotics supplementation exerts beneficial health effects. Since cigarette smoking reduces natural killer (NK) activity, we evaluated the effect of Lactobacillus casei Shirota (LcS) intake on NK cytotoxic activity in male smokers. The double-blind, placebo-controlled, randomised study was conducted on seventy-two healthy Italian blue-collar male smokers randomly divided for daily intake of LcS powder or placebo. Before and after 3 weeks of intake, peripheral blood mononuclear cells were isolated and NK activity and CD16⁺ cells' number were assessed. Daily LcS intake for 3 weeks significantly increased NK activity (P < 0.001). The increase in NK activity was paralleled by an increase in CD16⁺ cells (P < 0.001). Before intake, NK cytotoxic activity inversely correlated with the number of cigarettes smoked (R - 0.064). LcS intake prevented the smoke-dependent expected NK activity reduction. The analysis of the distribution of changes in smoke-adjusted NK activity demonstrated that the positive variations were significantly associated with LcS intake, while the negative variations were associated with placebo intake (median value of distributions of differences, 20.98 lytic unit (LU)/10⁷ cells for LcS v. - 4.38 LU/10⁷ cells for placebo, P = 0.039). In conclusion, 3 weeks of daily LcS intake in Italian male smokers was associated with a higher increase in cytotoxic activity and CD16⁺ cells' number in comparison to the placebo intake group.
authors.affiliation: Department of Oncology and Experimental Medicine, Nuovo Polo Didattico, University G. d'Annunzio, Chieti, Italy.
authors.forename: Marcella
authors.initials: M
authors.lastname: Reale
authors.forename: Paolo
authors.initials: P
authors.lastname: Boscolo
authors.forename: Veronica
authors.initials: V
authors.lastname: Bellante
authors.forename: Chiara
authors.initials: C
authors.lastname: Tarantelli
authors.forename: Marta
authors.initials: M
authors.lastname: Di Nicola
authors.forename: Laura
authors.initials: L
authors.lastname: Forcella
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Kanehisa
authors.initials: K
authors.lastname: Morimoto
authors.forename: Raffaella
authors.initials: R
authors.lastname: Muraro
mesh_terms: D000328:Adult; D001007:Anxiety / Q000517:prevention & control; D001294:Attitude to Health; D003602:Cytotoxicity, Immunologic; D004311:Double-Blind Method; D004651:Employment; D006304:Health Status; D006801:Humans; D007558:Italy; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D007780:Lacticaseibacillus casei / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D019936:Probiotics / Q000008:administration & dosage*; D017452:Receptors, IgG / Q000378:metabolism; D012907:Smoking / Q000009:adverse effects* / Q000276:immunology; D013312:Stress, Physiological; D013315:Stress, Psychological / Q000517:prevention & control; D011795:Surveys and Questionnaires
chemical_list: D017452:Receptors, IgG