BACKGROUND:The novel coronavirus disease 2019 (COVID-19) has become a global health emergency. The cumulative number of new confirmed cases and deaths are still increasing out of China. Independent predicted factors associated with fatal outcomes remain uncertain.RESEARCH QUESTION: The goal of the current study was to investigate the potential risk factors associated with fatal outcomes from COVID-19 through a multivariate Cox regression analysis and a nomogram model. STUDY DESIGN AND METHODS:A retrospective cohort of 1,590 hospitalized patients with COVID-19 throughout China was established. The prognostic effects of variables, including clinical features and laboratory findings, were analyzed by using Kaplan-Meier methods and a Cox proportional hazards model. A prognostic nomogram was formulated to predict the survival of patients with COVID-19. RESULTS:In this nationwide cohort, nonsurvivors included a higher incidence of elderly people and subjects with coexisting chronic illness, dyspnea, and laboratory abnormalities on admission compared with survivors. Multivariate Cox regression analysis showed that age $ 75 years (hazard ratio [HR], 7.86; 95% CI, 2. 44-25.35), age between 65 and 74 years (HR, 3.43; 95% CI, 1.24-9.5), coronary heart disease (HR, 4.28; 95% CI, 1.14-16.13), cerebrovascular disease (HR, 3.1; 95% CI, 1.07-8.94), dyspnea (HR, 3.96; 95% CI,, procalcitonin level > 0.5 ng/mL (HR, 8.72; 95% CI,, and aspartate aminotransferase level > 40 U/L (HR, 2.2; 95% CI, 1.1-6.73) were independent risk factors associated with fatal outcome. A nomogram was established based on the results of multivariate analysis. The internal bootstrap resampling approach suggested the nomogram has sufficient discriminatory power with a C-index of 0.91 (95% CI, 0.85-0.97). The calibration plots also showed good consistency between the prediction and the observation. INTERPRETATION:The proposed nomogram accurately predicted clinical outcomes of patients with COVID-19 based on individual characteristics. Earlier identification, more intensive surveillance, and appropriate therapy should be considered in patients at high risk.

The role of macrophages in the pathogenesis of acetaminophen (APAP)-induced liver injury remains controversial, as it has been demonstrated that these cells display pro-toxicant and hepato-protective functions. This controversy may stem from the heterogeneity and/or plasticity of macrophages and the difficulty in distinguishing and differentially studying subpopulations of macrophages in the liver. In the present study, using flow cytometric analysis and fluorescence-labeled antibodies against specific cell surface macrophage markers, we were able to, for the first time, identify an APAP-induced macrophage (IM) population distinct from resident Kupffer cells. The data demonstrated that the IMs were derived from circulating monocytes that infiltrated the liver following APAP-induced liver injury. The IMs exhibited a phenotype consistent with that of alternatively activated macrophages and demonstrated the ability to phagocytize apoptotic cells and induce apoptosis of neutrophils. Furthermore, in the absence of the IMs, the resolution of hepatic damage following APAP-induced hepatotoxicity was delayed in CCR2(-/-) mice compared with wild-type mice. These findings likely contribute to the role of the IMs in the processes of tissue repair, including counteracting inflammation and promoting angiogenesis. The present study also demonstrated the ability of separating populations of macrophages and delineating distinct functions of each group in future studies of inflammatory disease in the liver and other tissues.

The liver is known to favor the induction of immunological tolerance rather than immunity. Although Kupffer cells (KC) have been indicated to play a role in liver tolerance to allografts and soluble antigens, the mechanisms involved remain unclear. We hypothesized that KCs could promote immune tolerance by acting as incompetent antigen-presenting cells (APC), as well as actively suppressing T cell activation induced by other potent APCs. The expression of antigen presentation-related molecules by KCs was phenotyped by flow cytometry. The abilities of KCs to act as APCs and to suppress T cell activation induced by splenic dendritic cells (DC) were examined by in vitro proliferation assays using CD4 ؉ OVA-TCR (ovalbumin T cell receptor) transgenic T cells. We found that, compared with DCs, KCs expressed significantly lower levels of major histocompatibility complex (MHC) II, B7-1, B7-2, and CD40. This result is consistent with our observation that KCs were not as potent as DCs in eliciting OVA-specific T cell proliferation. However, KCs isolated from polyinosinic:polycytidylic acid-treated mice expressed significantly higher levels of MHC II and costimulatory molecules than did naïve KCs and could stimulate stronger T cell responses. More importantly, we found that KCs could inhibit DC-induced OVA-specific T cell activation. Further investigation of the underlying mechanism revealed that prostaglandins produced by KCs played an important role. The results ruled out the possible involvement of interleukin-10, nitric oxide, 2,3-dioxygenase, and transforming growth factor ␤ in KC-mediated T cell suppression. Conclusion: Our data indicate that KCs are a tolerogenic APC population within the liver. These findings suggest that KCs may play a critical role in regulating immune reactions within the liver and contributing to liver-mediated systemic immune tolerance. (HEPATOLOGY 2008;48:978-990.)

Objective: To evaluate the spectrum of comorbidities and its impact on the clinical outcome in patients with coronavirus disease 2019 . Design: Retrospective case studiesSetting: 575 hospitals in 31 province/autonomous regions/provincial municipalities across China Participants: 1,590 laboratory-confirmed hospitalized patients. Main outcomes and measures: Epidemiological and clinical variables (in particular, comorbidities)were extracted from medical charts. The disease severity was categorized based on the American Thoracic Society guidelines for community-acquired pneumonia. The primary endpoint was the composite endpoints, which consisted of the admission to intensive care unit (ICU), or invasive ventilation, or death. The risk of reaching to the composite endpoints was compared among patients with COVID-19 according to the presence and number of comorbidities.Results: Of the 1,590 cases, the mean age was 48.9 years. 686 patients (42.7%) were females. 647 (40.7%) patients were managed inside Hubei province, and 1,334 (83.9%) patients had a contact history of Wuhan city. Severe cases accounted for 16.0% of the study population. 131 (8.2%) patients reached to the composite endpoints. 399 (25.1%) reported having at least one comorbidity. : medRxiv preprint 5 malignancy and immunodeficiency, respectively. 130 (8.2%) patients reported having two or more comorbidities. Patients with two or more comorbidities had significantly escalated risks of reaching to the composite endpoint compared with those who had a single comorbidity, and even more so as compared with those without (all P<0.05). After adjusting for age and smoking status, patients with COPD (HR 2.681, 95%CI 1.424-5.048), diabetes (HR 1.59, 95%CI 1.03-2.45), hypertension (HR 1.58, 95%CI 1.07-2.32) and malignancy (HR 3.50, 95%CI 1.60-7.64) were more likely to reach to the composite endpoints than those without. As compared with patients without comorbidity, the HR (95%CI) was 1.79 (95%CI 1.16-2.77) among patients with at least one comorbidity and 2.59 (95%CI 1.61-4.17) among patients with two or more comorbidities. Conclusion:Comorbidities are present in around one fourth of patients with COVID-19 in China, and predispose to poorer clinical outcomes. FUNDING: Supported by National Health Commission, Department of Science and Technology of Guangdong Province. The funder had no role in the conduct of the study.

h Galectin-9 is a pleiotropic immune modulator affecting numerous cell types of innate and adaptive immunity. Patients with chronic infection with either hepatitis C virus (HCV) or HIV have elevated circulating levels. Limited data exist on the regulation of natural killer (NK) cell function through interaction with galectin-9. We found that galectin-9 ligation downregulates multiple immune-activating genes, including eight involved in the NK cell-mediated cytotoxicity pathway, impairs lymphokine-activated killing, and decreases the proportion of gamma interferon (IFN-␥)-producing NK cells that had been stimulated with interleukin-12 (IL-12)/IL-15. We demonstrate that the transcriptional and functional changes induced by galectin-9 are independent of Tim-3. Consistent with these results for humans, we find that the genetic absence of galectin-9 in mice is associated with greater IFN-␥ production by NK cells and enhanced degranulation. We also show that in the setting of a short-term (4-day) murine cytomegalovirus infection, terminally differentiated NKs accumulate in the livers of galectin-9 knockout mice, and that hepatic NKs spontaneously produce significantly more IFN-␥ in this setting. Taken together, our results indicate that galectin-9 engagement impairs the function of NK cells, including cytotoxicity and cytokine production.

CD56pos natural killer (NK)/natural T (NT) cells are important innate effectors providing the first line of defense against viral infection. Enhanced NK activity has been shown to protect from human immunodeficiency virus-1 infection. However, the role played by these innate effectors in protection against or development of hepatitis C virus (HCV) infection is unknown. We characterized CD56 pos populations in 11 injection drug users (IDUs) who remained uninfected despite being repeatedly exposed to HCV. NK profiles in exposed but uninfected (EU) individuals were compared with preinfection samples (median 90 days prior to HCV seroconversion) collected from 14 IDUs who were exposed and subsequently became infected (EI) and unexposed normal control subjects (n 5 8). Flow cytometric analysis of CD56 pos populations demonstrated that EUs had a higher proportion of CD56 low mature (P 5 0.0011) NK cells compared with EI subjects. Bead-isolated NKs (>90% purity) from EUs had significantly higher interleukin-2 (IL-2)-induced cytolytic activity against the NK-sensitive cell line K562 at an effector-to-target ratio of 10:1 (P < 0.0001). NKp30, a natural cytotoxicity receptor involved in NK activation, is highest on NK/NT cells in EUs relative to infected subjects. Using the JFH-1 infection system, we demonstrated that NKp30 high cells in the absence of exogenous stimulation significantly reduce infection of hepatocytes. Conclusion: CD56 pos populations in EUs are enriched for effector NKs displaying enhanced IL-2-induced cytolytic activity and higher levels of the natural cytotoxicity receptor NKp30-activating receptor. In addition, NKp30 high cells are more effective in preventing infection of Huh-7.5 cells than their NKp30 low/neg counterparts. These data support the hypothesis that NK cells contribute to anti-HCV defense in vivo in the earliest stages of infection, providing innate protection from HCV acquisition. (HEPATOLOGY 2010;52:1581-1589 H epatitis C virus (HCV), a member of the Flaviviridae family, is known for its high propensity to establish persistent infection.

Drug-induced liver injury (DILI) is a major safety concern in drug development. Its prediction and prevention have been hindered by limited knowledge of the underlying mechanisms, in part the result of a lack of animal models. We developed a mouse model of halothane-induced liver injury and characterized the mechanisms accounting for tissue damage. Female and male Balb/c, DBA/1, and C57BL/6J mice were injected intraperitoneally with halothane. Serum levels of alanine aminotransferase and histology were evaluated to determine liver injury. Balb/c mice were found to be the most susceptible strain, followed by DBA/1, with no significant hepatotoxicity observed in C57BL/6J mice. D rug-induced liver injury (DILI) represents a major health problem that challenges not only health care professionals but also the pharmaceutical industry and drug-regulatory agencies. In the United States, DILI accounts for as many as 25% of liver failure cases in intensive care units. 1 Due to its association with significant patient morbidity and mortality, DILI is currently the most common cause for the withdrawal of drugs from the pharmaceutical market. 2 The key to predicting and preventing DILI is a thorough understanding of the underlying mechanisms. Prospective human clinical trials would be impossible given the unpredictable nature and low incidence of DILI. Retrospective studies may be conducted; however, they will not yield mechanistic information on the development of DILI. In vitro experiments may be used as a means to understand isolated events in DILI development, but these experiments are not likely to provide insights into the complex molecular and cellular mechanisms of DILI. The best approach for these purposes is to perform animal studies.At present, the only widely studied model of DILI is the acetaminophen (APAP)-induced liver injury model, particularly in mice. Although important information on the mechanism(s) of drug-induced acute inflammatory injury has been obtained using this model, 3-10 APAP hepatotoxicity in mice or humans does not encompass the complete clinical spectrum nor all possible mechanistic

Corona Virus Disease 2019(COVID-19)-affected patients with severe immune abnormalities have a risk of cytokine release syndrome. The definition, prevention, and treatment of symptoms of cytokine release syndrome in critically ill patients with COVID-19 are important problems. This was a single-center case series of 11 COVID-19 patients with acute respiratory distress syndrome (ARDS) from The First Affiliated Hospital of Guangzhou Medical University in China from January 26, 2020 to February 18, 2020. The termination date of follow-up was February 19, 2020. In this single-center analysis of 11 critically ill patients with COVID-19, 8 patients were determined to have characteristics of cytokine release syndrome (CRS), including pulmonary inflammation, fever, and dysfunction of non-pulmonary organs; an increase of- Interleukin-6 (IL-6) in peripheral blood was the highest risk factor and an early indicator of CRS in COVID-19.