Small intestinal bacterial overgrowth (SIBO) is a condition hallmarked by an increase in the concentration of colonic-type bacteria in the small bowel. Watery diarrhea, bloating, abdominal pain and distension are the most common clinical manifestations. Additionally, malnutrition and vitamin (B12, D, A, and E) as well as minerals (iron and calcium) deficiency may be present. SIBO may mask or worsen the history of some diseases (celiac disease, irritable bowel disease), may be more common in some extra-intestinal disorders (scleroderma, obesity), or could even represent a pathogenetic link with some diseases, in which a perturbation of intestinal microbiota may be involved. On these bases, we performed a review to explore the multiple links between SIBO and digestive and extra-intestinal diseases.

Inflammatory bowel disease (IBD) may show a wide range of extraintestinal manifestations. In this context, liver involvement is a focal point for both an adequate management of the disease and its prognosis, due to possible serious comorbidity. The association between IBD and primary sclerosing cholangitis is the most known example. This association is relevant because it implies an increased risk of both colorectal cancer and cholangiocarcinoma. Additionally, drugs such as thiopurines or biologic agents can cause drug-induced liver damage; therefore, this event should be considered when planning IBD treatment. Additionally, particular consideration should be given to the evidence that IBD patients may have concomitant chronic viral hepatitis, such as hepatitis B and hepatitis C. Chronic immunosuppressive regimens may cause a hepatitis flare or reactivation of a healthy carrier state, therefore careful monitoring of these patients is necessary. Finally, the spread of obesity has involved even IBD patients, thus increasing the risk of non-alcoholic fatty liver disease, which has already proven to be more common in IBD patients than in the non-IBD population. This phenomenon is considered an emerging issue, as it will become the leading cause of liver cirrhosis.

Background Suboptimal anti-Sars-Cov2 vaccine response has been demonstrated during immunosuppressive treatments. Liver Transplant Recipients (LTRs) and Inflammatory Bowel Disease (IBD) patients are different setting of populations who are both undergoing immunosuppressive treatments. In this work, we pooled and compared, retrospectively, these two populations to evaluate anti-SARS-CoV2 seroconversion after the second dose of vaccination. Different comorbidities and therapies outcomes have been explored as well. Methods The antibody titres standardized of the two cohorts have been analysed. Matched patients of both populations for comorbidities and therapies with application of propensity score have been investigated. Results 240 LTRs and 424 IBD patients were analysed. Most have received an mRNA based vaccine (BNT162b2 or mRNA-1273: 99.1%). The seroconversion rate of 84% for LTRs and 93% for IBD patients was recorded. To multivariate analysis, hypertension (OR 2.8618, 95% CI 1.0012 to 8.1802), the mycophenolate administration (OR 2.9733, 95% CI 1.1820 to 7.4794) and the steroid use (OR 5.4531, 95% CI 1.0706 to 27.7761) were significantly associated with reduced seroconversion in LTRs cohort; meanwhile, the older age (OR 1.0369, 95% CI 1.0076 to 1.0670) and the thiopurine consumption (OR 2.9484, 95% CI 1.0089 to 8.6166) with that in IBD population. After Propensity Score Matching application, the seroconversion rates, not statistically different, of 86% for LTRs and 92% for IBD patients were found. Hypertension (OR 2.73, 95%CI 1.1258 to 6.6138), diabetes (OR 3.16, 95% CI 1.1888 to 8.4217), age > 65y (OR 2.93, 95% CI 1.1712 to 7.3153) and the female sex (OR 2.54, 95% CI 1.0963 to 5.9104) were correlated with reduced seroconversion in both populations. Conclusion After Propensity Score Matching, the seroconversion rates of IBD and LTR patients were not statistically different. Hypertension, diabetes and age > 65y revealed a significant influence on seroconversion and the female showed a reduced seroconversion in comparison to male.

IntroductionThe study of immune response to SARSCoV-2 infection in different solid organ transplant settings represents an opportunity for clarifying the interplay between SARS-CoV-2 and the immune system. In our nationwide registry study from Italy, we specifically evaluated, during the first wave pandemic, i.e., in non-vaccinated patients, COVID-19 prevalence of infection, mortality, and lethality in liver transplant recipients (LTRs), using non-liver solid transplant recipients (NL-SOTRs) and the Italian general population (GP) as comparators.MethodsCase collection started from February 21 to June 22, 2020, using the data from the National Institute of Health and National Transplant Center, whereas the data analysis was performed on September 30, 2020.To compare the sex- and age-adjusted distribution of infection, mortality, and lethality in LTRs, NL-SOTRs, and Italian GP we applied an indirect standardization method to determine the standardized rate.ResultsAmong the 43,983 Italian SOTRs with a functioning graft, LTRs accounted for 14,168 patients, of whom 89 were SARS-CoV-2 infected. In the 29,815 NL-SOTRs, 361 cases of SARS-CoV-2 infection were observed. The geographical distribution of the disease was highly variable across the different Italian regions. The standardized rate of infection, mortality, and lethality rates in LTRs resulted lower compared to NL-SOTRs [1.02 (95%CI 0.81-1.23) vs. 2.01 (95%CI 1.8-2.2); 1.0 (95%CI 0.5-1.5) vs. 4.5 (95%CI 3.6-5.3); 1.6 (95%CI 0.7-2.4) vs. 2.8 (95%CI 2.2-3.3), respectively] and comparable to the Italian GP.DiscussionAccording to the most recent studies on SOTRs and SARS-CoV-2 infection, our data strongly suggest that, in contrast to what was observed in NL-SOTRs receiving a similar immunosuppressive therapy, LTRs have the same risk of SARS-CoV-2 infection, mortality, and lethality observed in the general population. These results suggest an immune response to SARS-CoV-2 infection in LTRS that is different from NL-SOTRs, probably related to the ability of the grafted liver to induce immunotolerance.