Cellular strategies to induce immune tolerance after liver transplantation: Clinical perspectives.

Liver transplantation (LT) has become the most efficient treatment for pediatric and adult end-stage liver disease and the survival time after transplantation is becoming longer due to the development of surgical techniques and perioperative management. However, long-term side-effects of immunosuppressants, like infection, metabolic disorders and malignant tumor are gaining more attention. Immune tolerance is the status in which LT recipients no longer need to take any immunosuppressants, but the liver function and intrahepatic histology maintain normal. The approaches to achieve immune tolerance after transplantation include spontaneous, operational and induced tolerance. The first two means require no specific intervention but withdrawing immunosuppressant gradually during follow-up. No clinical factors or biomarkers so far could accurately predict who are suitable for immunosuppressant withdraw after transplantation. With the understanding to the underlying mechanisms of immune tolerance, many strategies have been developed to induce tolerance in LT recipients. Cellular strategy is one of the most promising methods for immune tolerance induction, including chimerism induced by hematopoietic stem cells and adoptive transfer of regulatory immune cells. The safety and efficacy of various cell products have been evaluated by prospective preclinical and clinical trials, while obstacles still exist before translating into clinical practice. Here, we will summarize the latest perspectives and concerns on the clinical application of cellular strategies in LT recipients.

[PD-1 is associated with CD8(+)T lymphocyte dysfunction in patients with acute and chronic liver failure].

Objective: To explore whether peripheral blood CD8(+)T lymphocyte dysfunction is correlated with the programmed death receptor-1 (PD-1) expression in patients with acute-on-chronic liver failure (HBV-ACLF). Methods: Peripheral blood mononuclear cells (PBMC) were collected from patients with HBV-ACLF and healthy controls. CD8(+)T lymphocytes number and PD-1 expression condition in CD8(+)T lymphocytes were detected by flow cytometry. CD8(+)T lymphocytes isolated from peripheral blood of HBV-ACLF patients were further cultured in vitro. One group was added with PD-L1-IgG fusion protein (ACLF+PD-1 group), and the other group was added with IgG fusion protein (ACLF group). Proliferation ability (ki67), cell viability (CD69), and secretion ability of effector cytokines (IL-2, IFN-γ, TNF-α) were analyzed. Results: 30 cases with HBV-ACLF and healthy controls were enrolled. CD8(+)T lymphocytes absolute number was significantly lower in the peripheral blood of patients with ACLF group (333.88 ± 147.74)/µl than healthy controls (872.50 ± 206.64)/µl (P < 0.001). PD-1 expression in peripheral blood CD8(+)T lymphocytes were significantly increased in ACLF group (13.33% ± 2.52%), (P = 0.027) than healthy controls (7.02% ± 2.12%). In in vitro culture, compared with healthy controls, the peripheral blood CD8(+)T lymphocytes cell viability (CD69), proliferation ability (ki67) (all P ​​< 0.001), and the level of cytokine production (IL-2, IFN-γ, TNF-α) (all P < 0.05) were equally weakened in patients with ACLF group. Compared with ACLF group, CD8(+)T cell viability (CD69), proliferation ability (KI67) (all P < 0.05), and the level of cytokine production were weakened in ACLF+PD-1 group (all P < 0.05). Conclusion: HBV-ACLF patients have CD8(+)T lymphocyte dysfunction. Therefore, PD-1 may have correlation in the regulation of CD8(+)T lymphocyte dysfunction in ACLF patients.

The Gut Microbiota-Derived Immune Response in Chronic Liver Disease.

In chronic liver disease, the causative factor is important; however, recently, the intestinal microbiome has been associated with the progression of chronic liver disease and the occurrence of side effects. The immune system is affected by the metabolites of the microbiome, and diet is the primary regulator of the microbiota composition and function in the gut-liver axis. These metabolites can be used as therapeutic material, and postbiotics, in the future, can increase or decrease human immunity by modulating inflammation and immune reactions. Therefore, the excessive intake of nutrients and the lack of nutrition have important effects on immunity and inflammation. Evidence has been published indicating that microbiome-induced chronic inflammation and the consequent immune dysregulation affect the development of chronic liver disease. In this research paper, we discuss the overall trend of microbiome-derived substances related to immunity and the future research directions.

The prognostic and diagnostic significance of the neutrophil-to-lymphocyte ratio in hepatocellular carcinoma: a prospective controlled study.

BACKGROUND: The neutrophil-lymphocyte ratio (NLR), a presumed measure of the balance between neutrophil-associated pro-tumour inflammation and lymphocyte-dependent antitumour immune function, has been suggested as a prognostic factor for several cancers, including hepatocellular carcinoma (HCC). METHODS: In this study, a prospectively accrued cohort of 781 patients (493 HCC and 288 chronic liver disease (CLD) without HCC) were followed-up for more than 6 years. NLR levels between HCC and CLD patients were compared, and the effect of baseline NLR on overall survival amongst HCC patients was assessed via multivariable Cox regression analysis. RESULTS: On entry into the study ('baseline'), there was no clinically significant difference in the NLR values between CLD and HCC patients. Amongst HCC patients, NLR levels closest to last visit/death were significantly higher compared to baseline. Multivariable Cox regression analysis showed that NLR was an independent prognostic factor, even after adjustment for the HCC stage. CONCLUSION: NLR is a significant independent factor influencing survival in HCC patients, hence offering an additional dimension in prognostic models.

Clinical Course and Risk Factors for Infection in Severe Forms of Alcohol-Associated Liver Disease.

BACKGROUND AND AIMS: Infection is a major driver of mortality in patients with advanced alcohol-associated liver disease (ALD). The epidemiology and clinical course of patients infected with life-threatening forms of ALD, including severe alcohol-associated hepatitis (sAH) and decompensated alcohol-associated cirrhosis (DAC), and specific risk factors for infection remain mostly unknown. APPROACH AND RESULTS: In this observational study, we assessed all infectious episodes occurring within a 90-day period from diagnosis in all consecutive patients with biopsy-proven sAH (modified Maddrey's discriminant function ≥ 32, Model for End-Stage Liver Disease [MELD] ≥ 18) and DAC (MELD ≥ 18) without alcohol-associated hepatitis in our tertiary hospital between 2003 and 2016. A total of 207 patients were included: 139 with sAH and 68 with DAC. One hundred seventeen (84%) patients with sAH and 41 (60%) patients with DAC experienced at least one infection episode at 90 days (P < 0.001). In multivariable analysis, factors associated with the development of infection were the presence of sAH and baseline MELD score. Bacterial infections represented the most common infection in the two groups, and only the MELD score was independently associated with the occurrence of bacterial infection. In both groups, pneumonia was the most prevalent bacterial infection, and gram-negative bacilli were the main pathogens. Invasive fungal infections (IFI) occurred in 20 (14.5%) patients with sAH and 3 (4.5%) with patients with DAC (P < 0.05). Multivariable regression showed that younger age, higher MELD, and corticosteroid therapy were independently associated with IFI. The 90-day cumulative incidence of death in patients infected with sAH and patients infected with DAC was 46% and 41.5%, respectively (P = 0.43). CONCLUSIONS: Patients with sAH are more susceptible to develop infection than those with DAC. In life-threatening forms of ALD, patients who were infected share a similar mortality rate. Corticosteroid treatment, not sAH, seems to be the main risk factor triggering IFI.

Cholangiopathy After Severe COVID-19: Clinical Features and Prognostic Implications.

INTRODUCTION: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 virus, is a predominantly respiratory tract infection with the capacity to affect multiple organ systems. Abnormal liver tests, mainly transaminase elevations, have been reported in hospitalized patients. We describe a syndrome of cholangiopathy in patients recovering from severe COVID-19 characterized by marked elevation in serum alkaline phosphatase (ALP) accompanied by evidence of bile duct injury on imaging. METHODS: We conducted a retrospective study of COVID-19 patients admitted to our institution from March 1, 2020, to August 15, 2020, on whom the hepatology service was consulted for abnormal liver tests. Bile duct injury was identified by abnormal liver tests with serum ALP > 3x upper limit of normal and abnormal findings on magnetic resonance cholangiopacreatography. Clinical, laboratory, radiological, and histological findings were recorded in a Research Electronic Data Capture database. RESULTS: Twelve patients were identified, 11 men and 1 woman, with a mean age of 58 years. Mean time from COVID-19 diagnosis to diagnosis of cholangiopathy was 118 days. Peak median serum alanine aminotransferase was 661 U/L and peak median serum ALP was 1855 U/L. Marked elevations of erythrocyte sedimentation rate, C-reactive protein, and D-dimers were common. Magnetic resonance cholangiopacreatography findings included beading of intrahepatic ducts (11/12, 92%), bile duct wall thickening with enhancement (7/12, 58%), and peribiliary diffusion high signal (10/12, 83%). Liver biopsy in 4 patients showed acute and/or chronic large duct obstruction without clear bile duct loss. Progressive biliary tract damage has been demonstrated radiographically. Five patients were referred for consideration of liver transplantation after experiencing persistent jaundice, hepatic insufficiency, and/or recurrent bacterial cholangitis. One patient underwent successful living donor liver transplantation. DISCUSSION: Cholangiopathy is a late complication of severe COVID-19 with the potential for progressive biliary injury and liver failure. Further studies are required to understand pathogenesis, natural history, and therapeutic interventions.

Macrophages in Chronic Liver Failure: Diversity, Plasticity and Therapeutic Targeting.

Chronic liver injury results in immune-driven progressive fibrosis, with risk of cirrhosis development and impact on morbidity and mortality. Persistent liver cell damage and death causes immune cell activation and inflammation. Patients with advanced cirrhosis additionally experience pathological bacterial translocation, exposure to microbial products and chronic engagement of the immune system. Bacterial infections have a high incidence in cirrhosis, with spontaneous bacterial peritonitis being the most common, while the subsequent systemic inflammation, organ failure and immune dysregulation increase the mortality risk. Tissue-resident and recruited macrophages play a central part in the development of inflammation and fibrosis progression. In the liver, adipose tissue, peritoneum and intestines, diverse macrophage populations exhibit great phenotypic and functional plasticity determined by their ontogeny, epigenetic programming and local microenvironment. These changes can, at different times, promote or ameliorate disease states and therefore represent potential targets for macrophage-directed therapies. In this review, we discuss the evidence for macrophage phenotypic and functional alterations in tissue compartments during the development and progression of chronic liver failure in different aetiologies and highlight the potential of macrophage modulation as a therapeutic strategy for liver disease.

Functional Characterization of Organoids Derived From Irreversibly Damaged Liver of Patients With NASH.

BACKGROUND AND AIMS: NASH will soon become the leading cause of liver transplantation in the United States and is also associated with increased COVID-19 mortality. Currently, there are no Food and Drug Administration-approved drugs available that slow NASH progression or address NASH liver involvement in COVID-19. Because animal models cannot fully recapitulate human NASH, we hypothesized that stem cells isolated directly from end-stage liver from patients with NASH may address current knowledge gaps in human NASH pathology. APPROACH AND RESULTS: We devised methods that allow the derivation, proliferation, hepatic differentiation, and extensive characterization of bipotent ductal organoids from irreversibly damaged liver from patients with NASH. The transcriptomes of organoids derived from NASH liver, but not healthy liver, show significant up-regulation of proinflammatory and cytochrome p450-related pathways, as well as of known liver fibrosis and tumor markers, with the degree of up-regulation being patient-specific. Functionally, NASH liver organoids exhibit reduced passaging/growth capacity and hallmarks of NASH liver, including decreased albumin production, increased free fatty acid-induced lipid accumulation, increased sensitivity to apoptotic stimuli, and increased cytochrome P450 metabolism. After hepatic differentiation, NASH liver organoids exhibit reduced ability to dedifferentiate back to the biliary state, consistent with the known reduced regenerative ability of NASH livers. Intriguingly, NASH liver organoids also show strongly increased permissiveness to severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) vesicular stomatitis pseudovirus as well as up-regulation of ubiquitin D, a known inhibitor of the antiviral interferon host response. CONCLUSION: Expansion of primary liver stem cells/organoids derived directly from irreversibly damaged liver from patients with NASH opens up experimental avenues for personalized disease modeling and drug development that has the potential to slow human NASH progression and to counteract NASH-related SARS-CoV-2 effects.

Circulating Macrophage Activation Markers Predict Transplant-Free Survival in Patients With Primary Sclerosing Cholangitis.

INTRODUCTION: Primary sclerosing cholangitis (PSC) is a progressive liver disease characterized by bile duct inflammation and fibrosis. The role of macrophages in PSC development and progression is less studied. Macrophage activation markers soluble (s)CD163 and mannose receptor (sMR) are associated with disease severity and outcome in other liver diseases, but not previously investigated in PSC. We evaluated sCD163 and sMR regarding disease severity and prognosis in patients with PSC. METHODS: We investigated 2 independent PSC cohorts from Oslo (n = 138) and Helsinki (n = 159) and analyzed blood sCD163 and sMR levels. The Mayo score, Enhanced Liver Fibrosis Test, and Amsterdam-Oxford model were assessed for comparison. RESULTS: Median (interquartile range) sCD163 was 3.32 (2.27-5.60) and 1.96 (1.47-2.70) mg/L in the Oslo and Helsinki cohorts, respectively, reflecting differences in disease severity between cohorts. Median sMR was similar in both cohorts, 0.28 (0.22-0.44) and 0.28 mg/L (0.20-0.36), respectively. In both cohorts, sCD163 and sMR levels raised with increasing disease severity (liver enzymes, Mayo score, and enhanced liver fibrosis test). Patients with high baseline levels of sCD163 had shorter transplant-free survival than patients with low baseline levels. Furthermore, sCD163 was associated with transplant-free survival in univariate cox-regression analyses. Both sCD163 and sMR performed better in the Oslo cohort of more severely diseased patients than those in the Helsinki cohort of more mildly diseased patients. DISCUSSION: Macrophage activation markers are elevated according to disease severity suggesting an important role of macrophages in PSC. Furthermore, sCD163 was identified as a prognostic marker and predictor of transplant-free survival in PSC (see Visual Abstract, Supplementary Digital Content 4, http://links.lww.com/CTG/A516).

Association between neutrophil-lymphocyte ratio change during living donor liver transplantation and graft survival.

Preoperative neutrophil-lymphocyte ratio (NLR), has shown a predictive value in living donor liver transplantation (LDLT). However, the change in the NLR during LDLT has not been fully investigated. We aimed to compare graft survival between the NLR increase and decrease during LDLT. From June 1997 to April 2019, we identified 1292 adult LDLT recipients with intraoperative NLR change. The recipients were divided according to NLR change: 103 (8.0%) in the decrease group and 1189 (92.0%) in the increase group. The primary outcome was graft failure in the first year. In addition, variables associated with NLR change during LDLT were evaluated. During 1-year follow-up, graft failure was significantly higher in the decrease group (22.3% vs. 9.1%; hazard ratio 1.87; 95% confidence interval 1.10-3.18; p = 0.02), but postoperative complications did not differ between two groups. This finding was consistent for the overall follow-up. Variables associated with NLR decrease included preoperative NLR > 4, model for end-stage liver disease score, intraoperative inotropic infusion and red blood cell transfusion, and operative duration. The least absolute shrinkage and selection operator model yielded similar results. NLR decrease during LDLT appeared to be independently associated with graft survival. Further studies are needed to confirm our findings.

Systemic inflammation increases across distinct stages of advanced chronic liver disease and correlates with decompensation and mortality.

BACKGROUND & AIMS: Distinct prognostic stages of advanced chronic liver disease (ACLD) are defined by severity of portal hypertension (PH) and the presence/absence of clinical complications. We characterised the degree of liver dysfunction, PH, and systemic inflammation across the distinct prognostic stages and assessed their relative impact on decompensation and mortality. METHODS: A single-centre, prospective cohort of ACLD patients undergoing hepatic venous pressure gradient (HVPG) measurement between 01/2017 and 08/2019 were classified into 6 prognostic stages: mild PH (HVPG 6-9 mmHg, S0), clinically significant PH (HVPG ≥10 mmHg without varices, S1), presence of varices (S2), history of variceal bleeding (S3), first non-bleeding decompensation (S4), and further decompensation (S5). The model for end-stage liver disease (MELD), C-reactive protein (CRP), and IL-6 levels were assessed in relation to their predictive value for decompensation and death. RESULTS: Among 168 ACLD patients 78 had compensated (cACLD, S0 = 13; S1 = 21; S2 = 44) and 90 had decompensated (dACLD, S3 = 10; S4 = 58; S5 = 22) disease. MELD increased across all stages (p <0.001), whereas HVPG mostly increased within cACLD substages. Significant increases in CRP and IL-6 levels were only noted across dACLD substages. IL-6 was an independent predictor of decompensation at 1-year follow-up in cACLD (hazard ratio [HR] 1.06, 95% CI 1.01-1.10; p = 0.013). In dACLD patients, IL-6 levels predicted death/transplantation after 1-year of follow-up (HR 1.02, 95% CI 1.01-1.03; p = 0.004). CONCLUSION: HVPG progression occurs mostly in cACLD patients, whereas systemic inflammation, as reflected by IL-6 levels, only increases substantially across dACLD stages. IL-6 levels correlate with the risk of first decompensation in cACLD and of death/transplantation in dACLD patients. LAY SUMMARY: Patients with advanced chronic liver disease (ACLD; i.e. liver cirrhosis) have a certain risk of mortality according to their stage of disease. Progression of disease is greatly influenced by increased pressure in the portal venous system (i.e. portal hypertension) and occurrence of clinical complications (i.e. decompensation). Our study demonstrates that systemic inflammation markedly increases across highest disease stages, and the inflammation biomarker IL-6 in blood may specifically indicate risk of disease progression in patients with ACLD. CLINICAL TRIALS REGISTRATION: The study is registered at ClinicalTrials.gov (NCT03267615).

Evidence for Increased Inflammatory Cytokine Profile in Hepatitis E Virus-Infected Obese Patients: Implications for Chronic Liver Disease.

We aimed to characterize the contribution of hepatitis E virus (HEV) in perpetuating the cytokine-mediated inflammatory setting related to liver damage in the context of obesity. Herein, serum samples from patients with liver disease were retrospectively analyzed and categorized as normal-weight patients (NW), overweight patients (OW), obese patients (ObP), and high alcohol consumer patients (HAC), and biochemical, anthropometrical, and transient elastography measurements were obtained. The positivity for immunoglobulin M (IgM) and immunoglobulin G (IgG) anti-HEV antibodies in samples was determined by enzyme-linked immunosorbent assay. Available samples from ObP were tested by reverse transcription-nested polymerase chain reaction for the presence of HEV-RNA. Cytokine profile in the serum of ObP was identified using a multiplexed immune assay. Globally, the highest frequency of IgG anti-HEV was found in ObP (57.5%), followed by HAC (20%), OW (15%), and NW (7.5%). A strong association between HEV serology and obesity was found (odds ratio = 4.21, confidence interval = 1.91.9.27) with a cutoff of 29.3 kg/m2 (area under curve [AUC] = 0-66; p = 0.003) and, a 23.7% of available samples of ObP provided amplification of HEV genome. Cytokine analysis revealed significantly higher levels of proinflammatory cytokines (interleukin [IL]-12, interferon [IFN]-γ, and IL-1ß) in IgG anti-HEV-positive ObP than in IgG anti-HEV-negative ObP. Moreover, a high proportion of patients with positive serology showed advanced liver damage. In conclusion, the high percentage of anti-HEV antibodies and viral RNA detection in the setting of an excess of fat, along with an associated proinflammatory cytokine profile found in IgG anti-HEV-positive ObP with more severe liver disease, support an interplay between HEV and obesity.

Extracellular gp96 is a crucial mediator for driving immune hyperactivation and liver damage.

Liver failure leads to the massive necrosis of hepatocytes, releasing large amounts of intracellular components including damage-associated molecular patterns (DAMPs). We found that extracellular gp96 levels in serum were elevated in patients with chronic hepatitis B infection (CHB) and acute-on-chronic liver failure (ACLF). Meanwhile, the gp96 level positively correlated with hepatic necroinflammation. We employed two mouse liver damage and liver failure models induced by lipopolysaccharide (LPS) plus D-galactosamine (D-Galn), and concanavalin A (ConA) to identify the function of extracellular gp96. As a result, the inhibition of extracellular gp96 by a specific peptide efficiently mitigated both LPS/D-Galn- and ConA-induced liver injury and immune hyperactivation, whereas exogenous gp96 aggravated the symptoms of hepatic injury in mice but not in Kupffer cells-ablated mice. The exposure of Kupffer cells to gp96 induced the secretion of pro-inflammatory cytokines. Collectively, our data demonstrate that gp96 released from necrotic hepatocytes aggravates immune hyperactivation and promotes liver damage and possibly the development of liver failure mainly by activating Kupffer cells.

Diagnosis and treatment of primary biliary cholangitis.

Primary biliary cholangitis is a cholestatic, chronic autoimmune liver disease with a wide individual variation in disease progression. The diagnosis is predominantly based on chronic elevation of alkaline phosphatase and the presence of anti-mitochondrial antibodies or other specific antinuclear antibodies (i.e. anti-gp210 and anti-sp100). Even in early-stage disease, health-related quality of life can be severely impaired by symptoms such as pruritus, fatigue, and sicca syndrome and metabolic bone disease should be assessed and treated. The prognosis of the disease is, however, largely determined by the development of cirrhosis and its complications. Ursodeoxycholic acid is associated with an improved prognosis and should be initiated and continued in all patients. Clinical outcome is related to the biochemical response to ursodeoxycholic acid, but the prognosis of those with an incomplete response is still better than those who remain untreated. Obeticholic acid was recently approved as second-line treatment and bezafibrate may serve as an adequate off-label alternative, particularly in patients with pruritus. Preliminary data suggest an additive effect of triple therapy with ursodeoxycholic acid, obeticholic acid, and bezafibrate, whereas other promising drugs are being evaluated in clinical trials.

Peritoneal Level of CD206 Associates With Mortality and an Inflammatory Macrophage Phenotype in Patients With Decompensated Cirrhosis and Spontaneous Bacterial Peritonitis.

BACKGROUND & AIMS: Peritoneal macrophages (PMs) regulate inflammation and control bacterial infections in patients with decompensated cirrhosis. We aimed to characterize PMs and associate their activation with outcomes of patients with spontaneous bacterial peritonitis (SBP). METHODS: We isolated PMs from ascites samples of 66 patients with decompensated cirrhosis (19 with SBP) and analyzed them by flow cytometry, quantitative real-time polymerase chain reaction, functional analysis, and RNA microarrays. We used ascites samples of a separate cohort of 111 patients with decompensated cirrhosis (67 with SBP) and quantified the soluble form of the mannose receptor (CD206) and tumor necrosis factor by enzyme-linked immunosorbent assay (test cohort). We performed logistic regression analysis to identify factors associated with 90-day mortality. We validated our findings using data from 71 patients with cirrhosis and SBP. Data from 14 patients undergoing peritoneal dialysis for end-stage renal disease but without cirrhosis were included as controls. RESULTS: We used surface levels of CD206 to identify subsets of large PMs (LPM) and small PMs (SPM), which differed in granularity and maturation markers, in ascites samples from patients with cirrhosis. LPMs vs SPMs from patients with cirrhosis had different transcriptomes; we identified more than 4000 genes that were differentially regulated in LPMs vs SPMs, including those that regulate the cycle, metabolism, self-renewal, and immune cell signaling. LPMs had an inflammatory phenotype, were less susceptible to tolerance induction, and released more tumor necrosis factor than SPMs. LPMs from patients with cirrhosis produced more inflammatory cytokines than LPMs from controls. Activation of PMs by Toll-like receptor agonists and live bacteria altered levels of CD206 on the surface of LPMs and release of soluble CD206. Analysis of serial ascites fluid from patients with SBP revealed loss of LPMs in the early phase of SBP, but levels increased after treatment. In the test and validation cohorts, patients with SBP and higher concentrations of soluble CD206 in ascites fluid (>0.53 mg/L) were less likely to survive for 90 days than those with lower levels. CONCLUSIONS: Surface level of CD206 can be used to identify mature, resident, inflammatory PMs in patients with cirrhosis. Soluble CD206 is released from activated LPMs and increased concentrations in patients with cirrhosis and SBP indicate reduced odds of surviving for 90 days.

Mucosal-Associated Invariant T Cells Redistribute to the Peritoneal Cavity During Spontaneous Bacterial Peritonitis and Contribute to Peritoneal Inflammation.

BACKGROUND & AIMS: Mucosal-associated invariant T (MAIT) cells are depleted from blood in patients with advanced liver disease and show features of immune dysfunction. Because circulating MAIT cells differ from organ-resident MAIT cells, we aimed to investigate the frequency, phenotype, and function of peritoneal MAIT cells from patients with cirrhosis and spontaneous bacterial peritonitis (SBP). METHODS: MAIT cells in blood and ascitic fluid from patients with cirrhosis were characterized using flow cytometry. Healthy individuals and noncirrhotic patients undergoing peritoneal dialysis served as controls. MAIT cell migration was studied in transwell assays. Cytokine release in response to infected ascitic fluid and bacterial products was assessed in vitro. RESULTS: Peritoneal CD3+ CD161hi Vα7.2+ T cells had an inflammatory, tissue retention phenotype, expressing the alpha E integrin, the chemokine receptors CCR5 and CXCR3, and the activation marker CD69 at higher levels than their circulating equivalents. Seventy-seven percent bound to MR1 tetramers loaded with the pyrimidine intermediate 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil. The ratio of peritoneal to blood MAIT cell frequency increased from 1.3 in the absence of SBP to 2.6 at diagnosis and decreased by day 3. MAIT cells migrated toward infected ascitic fluid containing CCL5 and CCL20 and released cytokines in an MR1-restricted fashion. Whereas the depleted circulating MAIT cell pool displayed features of immune exhaustion, peritoneal MAIT cells remained competent producers of inflammatory cytokines in response to bacterial products. Peritoneal MAIT activation correlated with systemic inflammation, suggesting a possible link between peritoneal and systemic immunity. CONCLUSIONS: Peritoneal MAIT cells phenotypically and functionally differ from circulating MAIT cells in decompensated cirrhosis and redistribute to the peritoneum during SBP.

Infections developing in patients undergoing liver transplantation: Recipients of living donors may be more prone to bacterial/fungal infections.

BACKGROUND/AIMS: Despite surgical advances in liver transplantation and effective prophylactic strategies, posttransplant infections are the most important cause of morbidity and mortality. Diagnosis and management of infections because of developing immunosuppression is difficult and adversely affects mortality. This study aimed to review bacterial and fungal infections in patients after liver transplantation and to reveal the resistance rates. MATERIALS AND METHODS: A total of 107 patients who underwent liver transplantation between January 2017 and February 2018 were evaluated retrospectively with regard to demographic characteristics, causes of transplantation, conditions that may lead to infection, postoperative infections, pathogens, and resistance patterns. RESULTS: Of the 107 patients who underwent liver transplantation, 48 (44.8%) had an infection. Bacterial infections were detected in 41% of the patients, and fungal infections were found in 13%. When we compared living and cadaveric transplants in terms of infection development, these rates were found to be 53% and 33%, respectively (p=0.034). No statistically significant results could be obtained when evaluating conditions such as sex, presence of underlying primary disease, Model for End-Stage Liver Disease MELD score, diabetes status, total parenteral nutrition, and risk factors for infection. CONCLUSION: After liver transplantation, infections are often seen in the first month of the postoperative period. Knowing the most common pathogens and resistance states in this process reduces infection-related deaths by providing appropriate treatment regimens at the right time.

Safety profile of autologous macrophage therapy for liver cirrhosis.

Therapies to reduce liver fibrosis and stimulate organ regeneration are urgently needed. We conducted a first-in-human, phase 1 dose-escalation trial of autologous macrophage therapy in nine adults with cirrhosis and a Model for End-Stage Liver Disease (MELD) score of 10-16 (ISRCTN 10368050). Groups of three participants received a single peripheral infusion of 107, 108 or up to 109 cells. Leukapheresis and macrophage infusion were well tolerated with no transfusion reactions, dose-limiting toxicities or macrophage activation syndrome. All participants were alive and transplant-free at one year, with only one clinical event recorded, the occurrence of minimal ascites. The primary outcomes of safety and feasibility were met. This study informs and provides a rationale for efficacy studies in cirrhosis and other fibrotic diseases.

Research Status of Mesenchymal Stem Cells in Liver Transplantation.

Liver transplantation has been deemed the best choice for end-stage liver disease patients but immune rejection after surgery is still a serious problem. Patients have to take immunosuppressive drugs for a long time after liver transplantation, and this often leads to many side effects. Mesenchymal stem cells (MSCs) gradually became of interest to researchers because of their powerful immunomodulatory effects. In the past, a large number of in vitro and in vivo studies have demonstrated the great potential of MSCs for participation in posttransplant immunomodulation. In addition, MSCs also have properties that may potentially benefit patients undergoing liver transplantation. This article aims to provide an overview of the current understanding of the immunomodulation achieved by the application of MSCs in liver transplantation, to discuss the problems that may be encountered when using MSCs in clinical practice, and to describe some of the underlying capabilities of MSCs in liver transplantation. Cell-cell contact, soluble molecules, and exosomes have been suggested to be critical approaches to MSCs' immunoregulation in vitro; however, the exact mechanism, especially in vivo, is still unclear. In recent years, the clinical safety of MSCs has been proven by a series of clinical trials. The obstacles to the clinical application of MSCs are decreasing, but large sample clinical trials involving MSCs are still needed to further study their clinical effects.

Long-term Seroprotection of Varicella-zoster Immunization in Pediatric Liver Transplant Recipients.

BACKGROUND: Chickenpox is a highly contagious vaccine-preventable disease that can lead to severe complications, especially in immunocompromised patients. Varicella-zoster virus (VZV) vaccine appears to be safe and immunogenic in pediatric solid organ transplant recipients, but there are few data on the long-term vaccine-induced seroprotection. METHODS: In this prospective interventional study, we offered 2 doses of VZV vaccine to all eligible and nonseroprotected children seen 1 year after liver transplant. Vaccine responses were measured 1 month later and yearly thereafter. Vaccine safety was closely monitored. A supplementary dose was administered if protective levels were not reached/maintained. RESULTS: Among 121 enrolled patients, 49 were vaccinated and followed during 5.5 years (interquartile range, 3.7-8.0). Their seroconversion rate reached 100% (97.5% confidence interval [CI], 92.7-100). Low VZV-antibody concentration (≤400 UI/L) after the first 1-2 dose/s was associated with the need for a supplementary dose (odds ratio, 15.0; 95% CI, 3.4-67.0, P = 0.001) and was given to 31% (15/47) of children at 1.1 year (interquartile range, 0.9-3.9). Although antibody concentrations declined during follow-up, 96% (95% CI, 86.0-99.5) of patients maintained protective antibody concentrations at a median of 5.5 years after vaccination. One breakthrough disease was identified. CONCLUSIONS: VZV immunization of pediatric solid organ transplant recipients confers sustained seroprotection.