This pilot study shows that CNCM I-1572 is able to modulate gut microbiota structure/function and reduce immune activation in IBS. As no statistically significant effect on IBS-symptoms was found, further studies are necessary to determine the role of this probiotic in IBS. The study was registered at ClinicalTrials.gov registry under identifier NCT02371499.

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Irritable bowel syndrome (IBS), a common functional gastrointestinal disorder, is classified according to bowel habits as IBS with constipation (IBS-C), with diarrhea (IBS-D), with alternating constipation and diarrhea (IBS-M), and unsubtyped (IBS-U). The mechanisms leading to the different IBS forms are mostly unknown. This study aims to evaluate whether specific fecal bacterial taxa and/or short-chain fatty acids (SCFAs) can be used to distinguish IBS subtypes and are relevant for explaining the clinical differences between IBS subcategories. We characterized five fecal samples collected at 4-weeks intervals from 40 IBS patients by 16S rRNA gene profiling and SCFA quantification. Finally, we investigated the potential correlations in IBS subtypes between the fecal microbial signatures and host physiological and clinical parameters. We found significant differences in the distribution of Clostridiales OTUs among IBS subtypes and reduced levels of SCFAs in IBS-C compared to IBS-U and IBS-D patients. Correlation analyses showed that the diverse representation of Clostridiales OTUs between IBS subtypes was associated with altered levels of SCFAs; furthermore, the same OTUs and SCFAs were associated with the fecal cytokine levels and stool consistency. Our results suggest that intestinal Clostridiales and SCFAs might serve as potential mechanistic biomarkers of IBS subtypes and represent therapeutic targets.

The current scientific research is continuously aiming at identifying new therapeutic targets with the purpose of modifying the immune response to allergens. The evolution in immunological methods has led to the identification of immunoglobulin E (IgE) as both a diagnostic biomarker and potential therapeutic target in allergic diseases, such as allergic rhinitis. Allergen immunotherapy has been used for more than 100 years to treat allergic diseases and it is today considered the only disease-modifying treatment capable of inducing a long-lasting immunological and clinical tolerance toward the causal allergen. During the past 20 years, major advances have been made in understanding the molecular and cellular mechanisms of allergen tolerance in humans. Moreover, there has been considerable progress in allergen extract modifications and additions to standard extracts. The recognition that IgE plays a pivotal role in basic regulatory mechanisms of allergic inflammation has recently stimulated research into the therapeutic potential of directly targeting this antibody. Omalizumab, the most advanced humanized anti-IgE monoclonal antibody, is currently approved for the treatment of uncontrolled allergic asthma and chronic spontaneous urticaria. Interesting results also arise from studies in which omalizumab was administered in patients with allergic rhinitis. The aim of this review is to provide an update on current findings on immunological and clinical effects of allergen immunotherapy and anti-IgE therapy, which have been shown to have synergistic modes of action for the treatment of allergic rhinitis.