## 4 Discussion
In an earlier study, the administration of _Lactobacillus_ and _Bifidobacterium_ species led to a significant increase in the modulation and regulation of immune responses through IL-10 (an anti-inflammatory cytokine) upregulation and TNF-\(\alpha\) (a proinflammatory cytokine) downregulation [31]. There are some adverse effects of probiotics on cytokines; according to [32], after 4 weeks of supplementation of yogurt containing probiotic strains, proinflammatory IFN-\(\gamma\) was observed to increase. There was an increase in TNF-\(\alpha\) and a decrease in IL-10 significantly in the yogurt supplementation group, but there were no statistical differences between the two study groups. However, the current study found that after 12 weeks of probiotic _L. paracasei_ HII01 supplementation, IFN-\(\gamma\) and IL-10 increased, whereas TNF-\(\alpha\) decreased, which is similar to the results of other studies on cytokine production. Another immunomodulatory property of probiotics is the regulation of toxin LPS production from intestinal bacteria. A previous study demonstrated that probioticic strain administration significantly reduced the LPS concentrations in plasma [33]. Moreover, [34] reported that probioticic consumption reduced plasma LPS and inflammatory responses induced by Gram-negative bacteria. Likewise, in the current study, after 12 weeks of the supplementation of _L. paracasei_ HII01, the LPS concentration in plasma appeared to decrease at the end of treatment, and a significant difference between the two groups was observed. Probiotics support gut microbiota to stimulate dendritic cells in order to produce proinflammatory cytokines, and they then promote macrophage/NK cells to neutralize LPS and eliminate pathogenic bacteria [35]. The health-related effects of probiotics, including the increase in IgA production and reduced chances of having a leaky gut, were observed in the current study. Immunoglobulin A has a vital role in encouraging adherence in the intestines and the survival of beneficial microorganisms. The study of probiotic _Lactobacillus_ in a rat model on the immune system's modulation by increasing the IgA levels in saliva showed that the IgA levels in the _Lactobacillus_ supplementation group were significantly higher than those in the control group [36]. Likewise, [37] also reported that probiotics enhanced the body's immune system by inducing IgA formation, macrophage activation, proinflammatory cytokines, and antioxidants. In humans, probiotics can stimulate and enhance secretory IgA production on mucosal surfaces or serum IgA in the circulation. In a probiotic consumption study of IgA concentrations, it was reported that IgA increased by approximately 10% after consuming the probiotic strains. It also supports the findings of the current research that suggest that the supplementation of probiotics increases IgA production. IgA was observed to increase after the supplementation of _L. paracasei_, and was significantly different to that of the placebo group. The human intestine's primary abilities are as follows: nutrient absorption, the provision of a barrier function, and the prevention of antigens and pathogens from entering the mucosal tissues, leading to inflammation and causing diseases. Some chronic inflammatory diseases can affect intestinal permeability, characterized by a leaky intestinal barrier, resulting in intestinal permeability. Tight junctions (TJ) are responsible for intestinal integrity [38]. Furthermore, a recent study reported that the imbalance of microbiota, especially high Gram-negative pathogenic bacteria in the intestines, could cause inflammation and induce increased intestinal permeability [39]. Lactulose mannitol ratio tests are clinically used to detect gut permeability changes due to the difference in the quantity of excreted lactose and mannitol.