Lactobacilli Supplemented with Larch Arabinogalactan and Colostrum Stimulates an Immune Response towards Peripheral NK Activation and Gut Tolerance.

Probiotics possibly affect local and systemic immune reactions and maintain the intestinal immune homeostasis in healthy individuals and patients with diseases such as irritable bowel syndrome (IBS). In this single-center, blinded trial, we enrolled 40 individuals (20 patients with IBS and 20 healthy individuals) whose blood and fecal samples were collected before and after a 21-day administration of a product comprising Lactobacillus spp., larch arabinogalactan, and colostrum. The percentage of HLA-DR+ natural killer (NK) cells was higher in healthy individuals (p = 0.03) than in patients with IBS after product supplementation. In the fecal samples of patients with IBS, we observed a decline in IL-6, IFN-γ, TNF-α, and secretory IgA levels and, simultaneously, an increase in IL-10 and IL-17A levels after supplementation, although non-significant, whereas, in healthy individuals, we observed a significant decline in IL-6 and IFN-γ levels after supplementation (p < 0.001). Nevertheless, we observed a clinical improvement of symptoms in 65-75% of patients with IBS and the complete resolution of the initial symptoms in five of the 20 patients. We also observed a possible prophylactic effect by the inducing system antiviral impact accompanied by a trend for local immune tolerance in the gut in healthy individuals, where it is the desirable state.