Background: Gastrointestinal infections represent a risk factor for functional gastrointestinal and somatoform extraintestinal disorders. We investigated the prevalence and relative risk (RR) of gastrointestinal and somatoform symptoms 5 months after SARS‐CoV‐2 infection compared with a control cohort.Methods: One hundred and sixty‐four SARS‐CoV‐2 infected patients and 183 controls responded to an online questionnaire about symptoms and signs during the acute phase of the infection and after 4.8 ± 0.3 months. Presence and severity of gastrointestinal symptoms, somatization, anxiety, and depression were recorded with standardized questionnaires. Stool form and presence of irritable bowel syndrome (IBS) were also recorded. Any association between exposure to infection and symptoms was evaluated by calculating crude and adjusted RR values and score differences with 95% confidence intervals (CI).Key Results: Fever, dyspnea, loss of smell/taste/weight, diarrhea, myalgia, arthralgia, and asthenia were reported by more than 40% of patients during the acute phase. Compared with controls, adjusted RRs for loose stools, chronic fatigue, and somatization were increased after infection: 1.88 (95% CI 0.99–3.54), 2.24 (95% CI 1.48–3.37), and 3.62 (95% CI 1.01–6.23), respectively. Gastrointestinal sequelae were greater in patients with diarrhea during the acute phase.Conclusions & Inferences: Mild gastroenterological symptoms persist 5 months after SARS‐CoV‐2 infection, in particular in patients reporting diarrhea in the acute phase. Infected patients are at increased risk of chronic fatigue and somatoform disorders, thus supporting the hypothesis that both functional gastrointestinal and somatoform disorders may have a common biological origin.

IFNγ-producing ex-Th17 cells [‘Th1/17’] were shown to play a key pathogenic role in experimental colitis and are abundant in the intestine. Here, we identified and characterised a novel, potentially colitogenic subset of Th17 cells in the intestine of patients with Crohn’s disease [CD]. Human Th17 cells expressing CCR5 [‘pTh17’] co-expressed T-bet and RORC/γt and produced very high levels of IL-17, together with IFN-γ. They had a gene signature of Th17 effector cells and were distinct from established Th1/17 cells. pTh17 cells, but not Th1/17 cells, were associated with intestinal inflammation in CD, and decreased upon successful anti-TNF therapy with infliximab. Conventional CCR5[-]Th17 cells differentiated to pTh17 cells with IL-23 in vitro. Moreover, anti-IL-23 therapy with risankizumab strongly reduced pTh17 cells in the intestine. Importantly, intestinal pTh17 cells were selectively activated by adherent-invasive Escherichia coli [AIEC], but not by a commensal/probiotic E. coli strain. AIEC induced high levels of IL-23 and RANTES from dendritic cells [DC]. Intestinal CCR5⁺Th1/17 cells responded instead to cytomegalovirus and were reduced in ulcerative colitis [UC], suggesting an unexpected protective role. In conclusion, we identified an IL-23–inducible subset of human intestinal Th17 cells. pTh17 cells produced high levels of pro-inflammatory cytokines, were selectively associated with intestinal inflammation in CD, and responded to CD-associated AIEC, suggesting a key colitogenic role.

INKT cells account for a relevant fraction of effector T-cells in the intestine and are considered an attractive platform for cancer immunotherapy. Although iNKT cells are cytotoxic lymphocytes, their functional role in colorectal cancer (CRC) is still controversial, limiting their therapeutic use. Thus, we examined the immune cell composition and iNKT cell phenotype of CRC lesions in patients (n = 118) and different murine models. High-dimensional single-cell flow-cytometry, metagenomics, and RNA sequencing experiments revealed that iNKT cells are enriched in tumor lesions. The tumor-associated pathobiont Fusobacterium nucleatum induces IL-17 and Granulocyte-macrophage colony-stimulating factor (GM-CSF) expression in iNKT cells without affecting their cytotoxic capability but promoting iNKT-mediated recruitment of neutrophils with polymorphonuclear myeloid-derived suppressor cells-like phenotype and functions. The lack of iNKT cells reduced the tumor burden and recruitment of immune suppressive neutrophils. iNKT cells in-vivo activation with α-galactosylceramide restored their anti-tumor function, suggesting that iNKT cells can be modulated to overcome CRC-associated immune evasion. Tumor co-infiltration by iNKT cells and neutrophils correlates with negative clinical outcomes, highlighting the importance of iNKT cells in the pathophysiology of CRC. Our results reveal a functional plasticity of iNKT cells in CRC, suggesting a pivotal role of iNKT cells in shaping the tumor microenvironment, with relevant implications for treatment.

Objectives: Ulcerative colitis (UC) is a chronic inflammatory disorder of unknown aetiology. Gut virome dysbiosis is fundamental in UC progression, although its role in the early phases of the disease is far from fully understood. Therefore, we sought to investigate the role of a virome-associated protein encoded by the Orthohepadnavirus genus, the hepatitis B virus X protein (HBx), in UC aetiopathogenesis. Design: HBx positivity of UC patient-derived blood and gut mucosa was assessed by RT-PCR and Sanger sequencing and correlated with clinical characteristics by multivariate analysis. Transcriptomics was performed on HBx-overexpressing endoscopic biopsies from healthy donors. C57BL/6 mice underwent intramucosal injections of liposome-conjugated HBx-encoding plasmids or the control, with or without antibiotic treatment. Multidimensional flow cytometry analysis was performed on colonic samples from HBx-treated and control animals. Transepithelial electrical resistance measurement, proliferation assay, chromatin immunoprecipitation assay with sequencing and RNA-sequencing were performed on in vitro models of the gut barrier. HBx-silencing experiments were performed in vitro and in vivo . Results: HBx was detected in about 45% of patients with UC and found to induce colonic inflammation in mice, while its silencing reverted the colitis phenotype in vivo . HBx acted as a transcriptional regulator in epithelial cells, provoking barrier leakage and altering both innate and adaptive mucosal immunity ex vivo and in vivo . Conclusion: This study described HBx as a contributor to the UC pathogenesis and provides a new perspective on the virome as a target for tailored treatments.

Aim: The aim of this study was to evaluate the correlation between hepatitis B core‐related antigen (HBcrAg) and hepatitis B virus (HBV) DNA and hepatitis B surface antigen (HBsAg) levels, and to investigate HBcrAg kinetics during nucleos(t)ide analogue (NA) or pegylated‐interferon (PEG‐IFN)‐α treatment in a cohort of chronic hepatitis B (CHB) genotype D patients.Methods: One hundred thirty eight sequential serum samples were collected from 28 hepatitis B e antigen‐negative CHB genotype D patients (20 men and 8 women; median age, 54 years [range, 47–58 years]) who underwent NA (n = 20) or PEG‐IFN‐α (n = 8) treatment. Serum HBcrAg levels were determined by chemiluminescent enzyme immunoassay. Longitudinal analysis was carried out at 6, 12, 24, and 36 months after NA treatment initiation and at 6, 12, and 18 months and at follow‐up month 6 after PEG‐IFN‐α treatment.Results: Basal HBcrAg levels were 4.7 ± 1.8 Log U/mL and 3.3 ± 1.6 Log U/mL in NA‐ and PEG‐IFN‐α‐treated patients, respectively. Hepatitis B core‐related antigen showed a moderate correlation with HBV DNA (r = 0.498, P < 0.0001) and no correlation with HBsAg (r = 0.192, P = 0.0669). In serial serum samples, a significant HBcrAg reduction was observed only in patients receiving NA (P = 0.019). In these patients, we observed a group (n = 12) with an early HBcrAg decline to undetectable levels between months 6–12, whereas the other group (n = 8) still had detectable HBcrAg at month 36 (4.4 ± 0.6 Log U/mL), independently from HBV DNA and HBsAg kinetics.Conclusions: Serum HBcrAg correlates with HBV DNA levels, most likely through expression of viral replication activity. We observed two different HBcrAg kinetics in NA‐treated patients, suggesting different relapse risk related to NA cessation. Further studies on larger patient cohorts will elucidate the role of HBcrAg in the safe discontinuation of NA in CHB genotype D patients.