In inflammatory bowel diseases (IBD), the therapeutic benefit and mucosal healing from specific probiotics may relate to the modulation of dendritic cells (DCs). Herein, we assessed the immunomodulatory effects of four probiotic strains including Lactobacillus salivarius, Bifidobacterium bifidum, Bacillus coagulans and Bacillus subtilis natto on the expression of co-stimulatory molecules, cytokine production and gene expression of signal-transducing receptors in DCs from IBD patients. Human monocyte-derived DCs from IBD patients and healthy controls were exposed to four probiotic strains. The expression of co-stimulatory molecules was assessed and supernatants were analyzed for anti-inflammatory cytokines. The gene expression of toll-like receptors (TLRs), IL-12p40 and integrin αvβ8 were also analyzed. CD80 and CD86 were induced by most probiotic strains in ulcerative colitis (UC) patients whereas only B. bifidum induced CD80 and CD86 expression in Crohn’s disease (CD) patients. IL-10 and TGF-β production was increased in a dose-independent manner while TLR expression was decreased by all probiotic bacteria except B. bifidum in DCs from UC patients. TLR-4 and TLR-9 expression was significantly downregulated while integrin ß8 was significantly increased in the DCs from CD patients. IL-12p40 expression was only significantly downregulated in DCs from CD patients. Our findings point to the general beneficial effects of probiotics in DC immunomodulation and indicate that probiotic bacteria favorably modulate the expression of co-stimulatory molecules, proinflammatory cytokines and TLRs in DCs from IBD patients.

Inflammatory bowel diseases (IBDs) are immune-mediated, chronic relapsing diseases with a rising prevalence worldwide in both adult and pediatric populations. Treatment options for immune-mediated diseases, including IBDs, are traditional steroids, immunomodulators, and biologics, none of which are capable of inducing long-lasting remission in all patients. Dendritic cells (DCs) play a fundamental role in inducing tolerance and regulating T cells and their tolerogenic functions. Hence, modulation of intestinal mucosal immunity by DCs could provide a novel, additional tool for the treatment of IBD. Recent evidence indicates that probiotic bacteria might impact immunomodulation both in vitro and in vivo by regulating DCs’ maturation and producing tolerogenic DCs (tolDCs) which, in turn, might dampen inflammation. In this review, we will discuss this evidence and the mechanisms of action of probiotics and their metabolites in inducing tolDCs in IBDs and some conditions associated with them.

In this study we indicated that impaired serological responses to SARS‐CoV‐2 infection among patients with IBD, could have significant implications for this group of patients and should be considered in vaccination program.

Ulcerative colitis (UC) is a chronic, relapsing inflammatory disease of the colon, often associated with gut microbial dysbiosis. Although anti-TNF-α agents, such as Adalimumab (Cinnora^®), are used to treat moderate-to-severe UC, the treatment response is highly variable. Identifying early microbial biomarkers of response could help support personalized therapeutic strategies and prevent unnecessary exposure to ineffective treatments. However, the long-term effects of anti-TNF therapy on both stool and mucosal microbiota remain poorly understood. This prospective longitudinal study included 23 corticosteroid-refractory or -dependent UC patients who started Adalimumab after endoscopy-confirmed flare-ups. Stool samples and inflamed colonic biopsies were collected at baseline, and 3 and 6 months. Microbiota profiling was performed using 16S rRNA sequencing. Microbial changes were analyzed over time and compared between responders (Mayo score 0–1) and non-responders (Mayo score ≥ 2). Sixty percent of patients achieved clinical remission. In responders, stool microbiota showed increased Bacteroidetes and decreased Proteobacteria abundances, along with an enrichment of beneficial taxa including Faecalibacterium prausnitzii, Bifidobacterium, and Akkermansia muciniphila. Mucosal microbiota exhibited persistent dysbiosis, characterized by an increase in Proteobacteria and a reduced Firmicutes/Proteobacteria ratio. Notably, responders showed distinct compartment-specific microbial changes, with a decrease in Gammaproteobacteria in stool and an increase in Corynebacterium in tissue. Adalimumab induces divergent microbial changes in stool and mucosa. While stool microbiota trends toward eubiosis in responders, persistent mucosal dysbiosis may reflect asymptomatic inflammation. These findings underscore the importance of niche-specific microbiome profiling in UC and support its integration into personalized treatment monitoring.