Self-renewing resident arterial macrophages arise from embryonic CX3CR1(+) precursors and circulating monocytes immediately after birth.

Resident macrophages densely populate the normal arterial wall, yet their origins and the mechanisms that sustain them are poorly understood. Here we use gene-expression profiling to show that arterial macrophages constitute a distinct population among macrophages. Using multiple fate-mapping approaches, we show that arterial macrophages arise embryonically from CX3CR1(+) precursors and postnatally from bone marrow-derived monocytes that colonize the tissue immediately after birth. In adulthood, proliferation (rather than monocyte recruitment) sustains arterial macrophages in the steady state and after severe depletion following sepsis. After infection, arterial macrophages return rapidly to functional homeostasis. Finally, survival of resident arterial macrophages depends on a CX3CR1-CX3CL1 axis within the vascular niche.

Congenic hematopoietic stem cell transplantation promotes survival of heart allografts in murine models of acute and chronic rejection.

The ability to induce tolerance would be a major advance in the field of solid organ transplantation. Here, we investigated whether autologous (congenic) hematopoietic stem cell transplantation (HSCT) could promote tolerance to heart allografts in mice. In an acute rejection model, fully MHC-mismatched BALB/c hearts were heterotopically transplanted into C57BL/6 (CD45.2) mice. One week later, recipient mice were lethally irradiated and reconstituted with congenic B6 CD45.1 Lin-Sca1+ckit+ cells. Recipient mice received a 14-day course of rapamycin both to prevent rejection and to expand regulatory T cells (Tregs). Heart allografts in both untreated and rapamycin-treated recipients that did not undergo HSCT were rejected within 33 days (median survival time = 8 days for untreated recipients, median survival time = 32 days for rapamycin-treated recipients), whereas allografts in HSCT-treated recipients had a median survival time of 55 days (P < 0.001 vs. both untreated and rapamycin-treated recipients). Enhanced allograft survival following HSCT was associated with increased intragraft Foxp3+ Tregs, reduced intragraft B cells, and reduced serum donor-specific antibodies. In a chronic rejection model, Bm12 hearts were transplanted into C57BL/6 (CD45.2) mice, and congenic HSCT was performed two weeks following heart transplantation. HSCT led to enhanced survival of allografts (median survival time = 70 days vs. median survival time = 28 days in untreated recipients, P < 0.01). Increased allograft survival post-HSCT was associated with prevention of autoantibody development and absence of vasculopathy. These data support the concept that autologous HSCT can promote immune tolerance in the setting of allotransplantation. Further studies to optimize HSCT protocols should be performed before this procedure is adopted clinically.

Evaluation of a gene expression biomarker to identify operationally tolerant liver transplant recipients: the LITMUS trial.

LITMUS was a single-centre, Phase 2a study designed to investigate whether the gene biomarker FGL2/IFNG previously reported for the identification of tolerance in murine models could identify operationally tolerant liver transplant recipients. Multiplex RT-PCR was used to amplify eight immunoregulatory genes in peripheral blood mononuclear cells (PBMC) from 69 adult liver transplant recipients. Patients with PBMC FGL2/IFNG ≥ 1 and a normal liver biopsy underwent immunosuppression (IS) withdrawal. The primary end point was the development of operational tolerance. Secondary end points included correlation of tolerance with allograft gene expression and immune cell markers. Twenty-eight of 69 patients (38%) were positive for the PBMC tolerance biomarker and 23 proceeded to IS withdrawal. Nine of the 23 patients had abnormal baseline liver biopsies and were excluded. Of the 14 patients with normal biopsies, eight (57%) have achieved operational tolerance and are off IS (range 12-57 months). Additional studies revealed that all of the tolerant patients and only one non-tolerant patient had a liver gene ratio of FOXP3/IFNG ≥ 1 prior to IS withdrawal. Increased CD4+ T regulatory T cells were detected both in PBMC and livers of tolerant patients following IS withdrawal. Higher expression of SELE (gene for E-selectin) and lower expression of genes associated with inflammatory responses (GZMB, CIITA, UBD, LSP1, and CXCL9) were observed in the pre-withdrawal liver biopsies of tolerant patients by RNA sequencing. These results suggest that measurement of PBMC FGL2/IFNG may enrich for the identification of operationally tolerant liver transplant patients, especially when combined with intragraft measurement of FOXP3/IFNG. Clinical Trial Registration: ClinicalTrials.gov (LITMUS: NCT02541916).

Complete Cycle Mapping Using a Quantitative At-Home Hormone Monitoring System in Prediction of Fertile Days, Confirmation of Ovulation, and Screening for Ovulation Issues Preventing Conception.

Background and Objectives: To achieve pregnancy, it is highly beneficial to identify the time of ovulation as well as the greater period of fertile days during which sperm may survive leading up to ovulation. Confirming successful ovulation is also critical to accurately diagnose ovulatory disorders. Ovulation predictor kits, fertility monitors, and tracking apps are all available to assist with detecting ovulation, but often fall short. They may not detect the full fertile window, provide accurate or real-time information, or are simply expensive and impractical. Finally, few over-the-counter products provide information to women about their ovarian reserve and future fertility. Therefore, there is a need for an easy, over-the-counter, at-home quantitative hormone monitoring system that assesses ovarian reserve, predicts the entire fertile window, and can screen for ovulatory disorders. Materials and Methods: Proov Complete is a four-in-one at-home multihormone testing system that utilizes lateral flow assay test strips paired with the free Proov Insight App to guide testing of four hormones-FSH, E1G, LH, and PdG-across the woman's cycle. In a pilot study, 40 women (including 16 with a fertility-related diagnosis or using fertility treatments) used Complete for one cycle. Results: Here, we demonstrate that Proov Complete can accurately and sensitively predict ovarian reserve, detect up to 6 fertile days and confirm if ovulation was successful, in one easy-to-use kit. Ovulation was confirmed in 38 cycles with a detectable PdG rise. An average of 5.3 fertile days (from E1G rise to PdG rise) were detected, with an average of 2.7 days prior to LH surge. Ovulation was confirmed via PdG rise an average of 2.6 days following the LH surge. While 38/40 women had a PdG rise, only 22 had a sustained PdG level above 5 µg/mL throughout the critical implantation window, indicating ovulatory dysfunction in 16 women. Conclusions: Proov Complete can detect the entire fertile window of up to 6 fertile days and confirm ovulation, while also providing information on ovarian reserve and guidance to clinicians and patients.

Donor outcomes in anonymous live liver donation.

BACKGROUND & AIMS: Death rates on liver transplant waiting lists range from 5%-25%. Herein, we report a unique experience with 50 anonymous individuals who volunteered to address this gap by offering to donate part of their liver to a recipient with whom they had no biological connection or prior relationship, so called anonymous live liver donation (A-LLD). METHODS: Candidates were screened to confirm excellent physical, mental, social, and financial health. Demographics and surgical outcomes were analyzed. Qualitative interviews after donation examined motivation and experiences. Validated self-reported questionnaires assessed personality traits and psychological impact. RESULTS: A total of 50 A-LLD liver transplants were performed between 2005 and 2017. Most donors had a university education, a middle-class income, and a history of prior altruism. Half were women. Median age was 38.5 years (range 20-59). Thirty-three (70%) learned about this opportunity through public or social media. Saving a life, helping others, generativity, and reciprocity for past generosity were motivators. Social, financial, healthcare, and legal support in Canada were identified as facilitators. A-LLD identified most with the personality traits of agreeableness and conscientiousness. The median hospital stay was 6 days. One donor experienced a Dindo-Clavien Grade 3 complication that completely resolved. One-year recipient survival was 91% in 22 adults and 97% in 28 children. No A-LLD reported regretting their decision. CONCLUSIONS: This is the first and only report of the characteristics, motivations and facilitators of A-LLD in a large cohort. With rigorous protocols, outcomes are excellent. A-LLD has significant potential to reduce the gap between transplant organ demand and availability. LAY SUMMARY: We report a unique experience with 50 living donors who volunteered to donate to a recipient with whom they had no biological connection or prior relationship (anonymous living donors). This report is the first to discuss motivations, strategies and facilitators that may mitigate physical, social and ethical risk factors in this patient population. With rigorous protocols, anonymous liver donation and recipient outcomes are excellent; with appropriate clinical expertise and system facilitators in place, our experience suggests that other centers may consider the procedure for its significant potential to reduce the gap between transplant organ demand and availability.

Surgical Complications after Right Hepatectomy for Live Liver Donation: Largest Single-Center Western World Experience.

The authors assessed the incidence, management, and risk factors for postoperative complications after right lobe (RL) live donor hepatectomy in a high-volume center in North America. All donors undergoing an RL live donor hepatectomy between 2000 and 2017 at our institution were included. The primary outcome was the development of complications (both medical and surgical). Predictors of postoperative complications were determined by logistic regression. A total of 587 patients underwent RL live donor hepatectomy. Among those, 187 postoperative complications were diagnosed in 141 (24%) patients. One patient had >90-day morbidity, and there were no donor deaths. Overall complications were significantly higher in the first era, 2000 to 2008 (81 [57.4%]) versus the second era, 2009 to 2017 (60 [42.6%]) (p = 0.01). On multivariate analysis, the only predictor of postoperative complications was the center volume of RL live donor hepatectomy in the previous 12 months with an odds ratio of 0.97 (95% confidence interval: 0.95-0.99). In conclusion, increasing center volume is associated with lower rates of postoperative complications after RL living liver donation.

Inhibition of the Fibrinogen-Like Protein 2:FcγRIIB/RIII immunosuppressive pathway enhances antiviral T-cell and B-cell responses leading to clearance of lymphocytic choriomeningitis virus clone 13.

Persistent viruses evade immune detection by interfering with virus-specific innate and adaptive antiviral immune responses. Fibrinogen-like protein-2 (FGL2) is a potent effector molecule of CD4+  CD25+  FoxP3+ regulatory T cells and exerts its immunosuppressive activity following ligation to its cognate receptor, FcγRIIB/RIII. The role of FGL2 in the pathogenesis of chronic viral infection caused by lymphocytic choriomeningitis virus clone-13 (LCMV cl-13) was assessed in this study. Chronically infected fgl2+/+ mice had increased plasma levels of FGL2, with reduced expression of the maturation markers, CD80, CD86 and MHC-II on macrophages and dendritic cells and impaired production of neutralizing antibody. In contrast, fgl2-/- mice or fgl2+/+ mice that had been pre-treated with antibodies to FGL2 and FcγRIIB/RIII and then infected with LCMV cl-13 developed a robust CD4+ and CD8+ antiviral T-cell response, produced high titred neutralizing antibody to LCMV and cleared LCMV. Treatment of mice with established chronic infection with antibodies to FGL2 and FcγRIIB/RIII was shown to rescue the number and functionality of virus-specific CD4+ and CD8+ T cells with reduced total and virus-specific T-cell expression of programmed cell death protein 1 leading to viral clearance. These results demonstrate an important role for FGL2 in viral immune evasion and provide a rationale to target FGL2 to treat patients with chronic viral infection.

Efficacy and safety of everolimus with reduced tacrolimus in living-donor liver transplant recipients: 12-month results of a randomized multicenter study.

In a multicenter, open-label, study, 284 living-donor liver transplant patients were randomized at 30 ± 5 days posttransplant to start everolimus+reduced tacrolimus (EVR+rTAC) or continue standard tacrolimus (TAC Control). EVR+rTAC was non-inferior to TAC Control for the primary efficacy endpoint of treated BPAR, graft loss or death at 12 months posttransplant: difference -0.7% (90% CI -5.2%, 3.7%); P < .001 for non-inferiority. Treated BPAR occurred in 2.2% and 3.6% of patients, respectively. The key secondary endpoint, change in estimated glomerular filtration rate (eGFR) from randomization to month 12, achieved non-inferiority (P < .001 for non-inferiority), but not superiority and was similar between groups overall (mean -8.0 vs. -12.1 mL/min/1.73 m2 , P = .108), and in patients continuing randomized treatment (-8.0 vs. -13.3 mL/min/1.73 m2 , P = .046). In the EVR+rTAC and TAC control groups, study drug was discontinued in 15.5% and 17.6% of patients, adverse events with suspected relation to study drug occurred in 57.0% and 40.4%, and proteinuria ≥1 g/24 h in 9.3% and 0%, respectively. Everolimus did not negatively affect liver regeneration. At 12 months, hepatocellular recurrence was only seen in the standard TAC-treated patients (5/62; 8.1%). In conclusion, early introduction of EVR+rTAC was non-inferior to standard tacrolimus in terms of efficacy and renal function at 12 months, with hepatocellular carcinoma recurrence only in TAC Control patients. ClinicalTrials.gov Identifier: NCT01888432.

Live donor liver transplantation with older donors: Increased long-term graft loss due to HCV recurrence.

Using our prospectively collected database all adult hepatitis C virus (HCV)-positive patients receiving an adult-to-adult LDLT between October 2000 and May 2014 were identified. Outcome of LDLT with grafts from younger (<50 years=128) vs older donors (≥50 years=31) was compared. Post-transplant graft function, postoperative complications and incidence of HCV recurrence were evaluated. Long-term graft and patient survival was calculated. No difference in graft function was observed between younger and older grafts. Overall complications were similar between both groups. The severity of complications determined by the Dindo-Clavien score was similar. Graft loss from HCV recurrence was significantly less frequent in younger grafts (18% vs 62%, P = 0.001). Young vs older livers had a trend toward improved 1-, 5-, and 10-year graft survival (89% vs 87%, 77% vs 69%, 70% vs 55%, P = 0.096), while patient survival was comparable between both groups (91% vs 90%, 78% vs 69%, 71% vs 60%, P = 0.25). In conclusion, LDLT with older vs younger grafts are more frequently associated with long-term graft loss due to HCV recurrence. Differences in graft survival might be more prominent with prolonged (≥5-year) follow-up. Living donor-recipient matching is particularly important for younger HCV-positive recipients.

Acute Rejection Increases Risk of Graft Failure and Death in Recent Liver Transplant Recipients.

BACKGROUND & AIMS: Acute rejection is detrimental to most transplanted solid organs, but is considered to be less of a consequence for transplanted livers. We evaluated risk factors for and outcomes after biopsy-proven acute rejection (BPAR) based on an analysis of a more recent national sample of recipients of liver transplants from living and deceased donors. METHODS: We analyzed data from the Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL) from 2003 through 2014 as the exploratory cohort and the Scientific Registry of Transplant Recipients (SRTR) from 2005 through 2013 as the validation cohort. We examined factors associated with time to first BPAR using multivariable Cox regression or discrete-survival analysis. Competing risks methods were used to compare causes of death and graft failure between recipients of living and deceased donors. RESULTS: At least 1 BPAR episode occurred in 239 of 890 recipients in A2ALL (26.9%) and 7066 of 45,423 recipients in SRTR (15.6%). In each database, risk of rejection was significantly lower when livers came from biologically related living donors (A2ALL hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.43-0.76; and SRTR HR, 0.78; 95% CI, 0.66-0.91) and higher in liver transplant recipients with primary biliary cirrhosis, of younger age, or with hepatitis C. In each database, BPAR was associated with significantly higher risks of graft failure and death. The risks were highest in the 12 month post-BPAR period in patients whose first episode occurred more than 1 year after liver transplantation: HRs for graft failure were 6.79 in A2ALL (95% CI, 2.64-17.45) and 4.41 in SRTR (95% CI, 3.71-5.23); HRs for death were 8.81 in A2ALL (95% CI, 3.37-23.04) and 3.94 in SRTR (95% CI, 3.22-4.83). In analyses of cause-specific mortality, associations were observed for liver-related (graft failure) causes of death but not for other causes. CONCLUSIONS: Contrary to previous data, acute rejection after liver transplant is associated with significantly increased risk of graft failure, all-cause mortality, and graft failure-related death, regardless of primary liver disease etiology. Living donor liver transplantation from a biologically related donor is associated with decreased risk of rejection.

GITR intrinsically sustains early type 1 and late follicular helper CD4 T cell accumulation to control a chronic viral infection.

CD4 T cells are critical for control of persistent infections; however, the key signals that regulate CD4 T help during chronic infection remain incompletely defined. While several studies have addressed the role of inhibitory receptors and soluble factors such as PD-1 and IL-10, significantly less work has addressed the role of T cell co-stimulatory molecules during chronic viral infection. Here we show that during a persistent infection with lymphocytic choriomeningitis virus (LCMV) clone 13, mice lacking the glucocorticoid-induced tumor necrosis factor receptor related protein (GITR) exhibit defective CD8 T cell accumulation, increased T cell exhaustion and impaired viral control. Differences in CD8 T cells and viral control between GITR+/+ and GITR-/- mice were lost when CD4 T cells were depleted. Moreover, mixed bone marrow chimeric mice, as well as transfer of LCMV epitope-specific CD4 or CD8 T cells, demonstrated that these effects of GITR are largely CD4 T cell-intrinsic. GITR is dispensable for initial CD4 T cell proliferation and differentiation, but supports the post-priming accumulation of IFNγ+IL-2+ Th1 cells, facilitating CD8 T cell expansion and early viral control. GITR-dependent phosphorylation of the p65 subunit of NF-κB as well as phosphorylation of the downstream mTORC1 target, S6 ribosomal protein, were detected at day three post-infection (p.i.), and defects in CD4 T cell accumulation in GITR-deficient T cells were apparent starting at day five p.i. Consistently, we pinpoint IL-2-dependent CD4 T cell help for CD8 T cells to between days four and eight p.i. GITR also increases the ratio of T follicular helper to T follicular regulatory cells and thereby enhances LCMV-specific IgG production. Together, these findings identify a CD4 T cell-intrinsic role for GITR in sustaining early CD8 and late humoral responses to collectively promote control of chronic LCMV clone 13 infection.

Live Donor Liver Transplantation With Older (≥50 Years) Versus Younger (<50 Years) Donors: Does Age Matter?

OBJECTIVE: To compare the outcome of adult live donor liver transplantation (LDLT) with grafts from older versus younger donors. INTRODUCTION: Using older donor grafts for adult LDLT may help expand the donor pool. However, the risks of LDLT with older donors remain controversial, and many centers are reluctant to use live donors aged 45 years or older for adult LDLT. METHODS: Outcomes of patients receiving a LDLT graft from donors aged 50 years or older (n = 91) were compared with those receiving a live donor graft from donors younger than 50 years (n = 378). RESULTS: Incidences of biliary (LDLT <50: 24% vs LDLT ≥50: 23%; P = 0.89) and major complications (LDLT <50: 24% vs LDLT ≥50: 24%; P = 1) were similar between both groups of recipients. No difference was observed in 30-day recipient mortality (LDLT <50: 3% vs LDLT ≥50: 0%; P = 0.13). The 1- (90% vs 90%), 5- (82% vs 73%), and 10- (71% vs 58%) year graft survival was statistically similar between both groups (P = 0.075). Likewise, patient survival after 1- (92% vs 96%), 5- (83% vs 79%), and 10- (76% vs 69%) years was also similar (P = 0.686). Overall, donors rate of major complications (Dindo-Clavien ≥3b) within 30 days was low (n = 2.3%) and not different in older versus younger donors (P = 1). Donor median hospital stay in both groups was identical [LDLT <50: 6 (4-17) vs LDLT ≥50: 6 (4-14) days; P = 0.65]. No donor death occurred and all donors had full recovery and returned to baseline activity. CONCLUSIONS: Right lobe LDLT with donors aged 50 years or older results in acceptable recipient outcome without increased donor morbidity or mortality. Potential live donors should not be declined on the basis of age alone.

Endometrial Effects of Prolonged Therapy with the Selective Progesterone Receptor Modulator Ulipristal Acetate: A Case Report.

BACKGROUND: Prolonged exposure to a selective progesterone receptor modulator (ulipristal acetate) in a patient with benign metastasizing leiomyoma did not result in endometrial hyperplasia or neoplasia. CASE: A woman with history of benign metastasizing leiomyoma underwent medical treatment for 5 years with ulipristal acetate. Endometrial biopsies were performed at established intervals to monitor for intraepithelial neoplasia or progesterone receptor modulator-associated endometrial changes (PAECs). The patient tolerated UPA therapy well; there was no evidence of hyperplasia or proliferative changes associated with progesterone-associated endometrial changes. CONCLUSION: In this case prolonged exposure to ulipristal acetate did not result in premalignant or malignant endometrial pathology.

Fostering liver living donor liver transplantation.

PURPOSE OF REVIEW: The review discusses issues pertinent to fostering professional and public interest in living donor liver transplantation. We discuss practices that we have adopted at our center, issues that have arisen and provide suggestions to expand live donor transplantation. RECENT FINDINGS: To bridge the gap between the current supply and demand of deceased donor organs, the transplant program in Toronto established the busiest live donor liver transplant program in the western world. To date, we have performed 664 live liver donor procedures with no donor deaths and excellent recipient and donor outcomes. To foster and grow live donation, we established a strong culture supporting live donation; hired a full-time, dedicated team of individuals to support the live donor program; obtained financial support for donors through a partnership agreement with the Trillium Gift of Life Network; developed linkages with the media, community service groups and the general public; generated patient education materials; and established a website. SUMMARY: With the present and future trends of deceased donation worldwide, we anticipate that live liver donation will remain an important option to fully meet the needs of patients requiring liver transplantation for the foreseeable future.

The regulatory T cell effector molecule fibrinogen-like protein 2 is necessary for the development of rapamycin-induced tolerance to fully MHC-mismatched murine cardiac allografts.

Therapies that promote tolerance in solid organ transplantation will improve patient outcomes by eliminating the need for long-term immunosuppression. To investigate mechanisms of rapamycin-induced tolerance, C3H/HeJ mice were heterotopically transplanted with MHC-mismatched hearts from BALB/cJ mice and were monitored for rejection after a short course of rapamycin treatment. Mice that had received rapamycin developed tolerance with indefinite graft survival, whereas untreated mice all rejected their grafts within 9 days. In vitro, splenic mononuclear cells from tolerant mice maintained primary CD4(+) and CD8(+) immune responses to donor antigens consistent with a mechanism that involves active suppression of immune responses. Furthermore, infection with lymphocytic choriomeningitis virus strain WE led to loss of tolerance suggesting that tolerance could be overcome by infection. Rapamycin-induced, donor-specific tolerance was associated with an expansion of regulatory T (Treg) cells in both the spleen and allograft and elevated plasma levels of fibrinogen-like protein 2 (FGL2). Depletion of Treg cells with anti-CD25 (PC61) and treatment with anti-FGL2 antibody both prevented tolerance induction. Tolerant allografts were populated with Treg cells that co-expressed FGL2 and FoxP3, whereas rejecting allografts and syngeneic grafts were nearly devoid of dual-staining cells. We examined the utility of an immunoregulatory gene panel to discriminate between tolerance and rejection. We observed that Treg-associated genes (foxp3, lag3, tgf-ß and fgl2) had increased expression and pro-inflammatory genes (ifn-γ and gzmb) had decreased expression in tolerant compared with rejecting allografts. Taken together, these data strongly suggest that Treg cells expressing FGL2 mediate rapamycin-induced tolerance. Furthermore, a gene biomarker panel that includes fgl2 can distinguish between rejecting and tolerant grafts.

Protein interferon-stimulated gene 15 conjugation delays but does not overcome coronavirus proliferation in a model of fulminant hepatitis.

UNLABELLED: Coronaviruses express a deubiquitinating protein, the papain-like protease-2 (PLP2), that removes both ubiquitin and the ubiquitin-like interferon (IFN)-stimulated gene 15 (ISG15) protein from target proteins. ISG15 has antiviral activity against a number of viruses; therefore, we examined the effect of ISG15 conjugation (ISGylation) in a model of acute viral hepatitis induced by the murine hepatitis virus strain 3 (MHV-3) coronavirus. Mice deficient in the ISG15 deconjugating enzyme, ubiquitin-specific peptidase-18 (USP18), accumulate high levels of ISG15-conjugated proteins and are hypersensitive to type I IFN. Infecting USP18(-/-) mice with MHV-3 resulted in extended survival (8 ± 1.2 versus 4 days) and in improved liver histology, a decreased inflammatory response, and viral titers 1 to 2 logs lower than in USP18(+/+) mice. The suppression of viral replication was not due to increased IFN since infected USP18(-/-) mice had neither increased hepatic IFN-α, -ß, or -γ mRNA nor circulating protein. Instead, delayed MHV-3 replication coincided with high levels of cellular ISGylation. Decreasing ISGylation by knockdown of the ISG15 E1 enzyme, Ube1L, in primary USP18(+/+) and USP18(-/-) hepatocytes led to increased MHV-3 replication. Both in vitro and in vivo, increasing MHV-3 titers were coincident with increased PLP2 mRNA and decreased ISGylation over the course of infection. The pharmacologic inhibition of the PLP2 enzyme in vitro led to decreased MHV-3 replication. Overall, these results demonstrate the antiviral effect of ISGylation in an in vivo model of coronavirus-induced mouse hepatitis and illustrate that PLP2 manipulates the host innate immune response through the ISG15/USP18 pathway. IMPORTANCE: There have been a number of serious worldwide pandemics due to widespread infections by coronavirus. This virus (in its many forms) is difficult to treat, in part because it is very good at finding "holes" in the way that the host (the infected individual) tries to control and eliminate the virus. In this study, we demonstrate that an important host viral defense-the ISG15 pathway-is only partially effective in controlling severe coronavirus infection. Activation of the pathway is very good at suppressing viral production, but over time the virus overwhelms the host response and the effects of the ISG15 pathway. These data provide insight into host-virus interactions during coronavirus infection and suggest that the ISG15 pathway is a reasonable target for controlling severe coronavirus infection although the best treatment will likely involve multiple pathways and targets.

Liver transplantation in patients with end-stage liver disease requiring intensive care unit admission and intubation.

Data regarding transplantation outcomes in ventilated intensive care unit (ICU)-dependent patients with end-stage liver disease (ESLD) are conflicting. This single-center cohort study investigated the outcomes of patients with ESLD who were intubated with mechanical support before liver transplantation (LT). The ICU plus intubation group consisted of 42 patients with decompensated cirrhosis and mechanical ventilation before transplantation. LT was considered for intubated ICU patients if the fraction of inspired oxygen was ≤40% with a positive end-expiratory pressure ≤ 10, low pressor requirements, and the absence of an active infection. Intubated ICU patients were compared to 80 patients requiring ICU admission before transplantation without intubation and to 126 matched non-ICU-bound patients. Patients requiring ICU care with intubation and ICU care alone had more severe postoperative complications than non-ICU-bound patients. Intubation before transplantation was associated with more postoperative pneumonias (15% in intubated ICU transplant candidates, 5% in ICU-bound but not intubated patients, and 3% in control group patients; P = 0.02). Parameters of reperfusion injury and renal function on postoperative day (POD) 2 and POD 7 were similar in all groups. Bilirubin levels were higher in the ICU plus intubation group at POD 2 and POD 7 after transplantation but were normalized in all groups within 3 months. The ICU plus intubation group versus the ICU-only group and the non-ICU group had decreased 1-, 3-, and 5-year graft survival (81% versus 84% versus 92%, 76% versus 78% versus 87%, and 71% versus 77% versus 84%, respectively; P = 0.19), but statistical significance was not reached. A Glasgow coma scale score of <7 versus >7 before transplantation was associated with high postoperative mortality in ICU-bound patients requiring intubation (38% versus 23%; P = 0.01). In conclusion, ICU admission and mechanical ventilation should not be considered contraindications for LT. With careful patient selection, acceptable long-term outcomes can be achieved despite increased postoperative complications.

Recipient factors associated with having a potential living donor for liver transplantation.

Because of a persistent discrepancy between the demand for liver transplantation (LT) and the supply of deceased donor organs, there is an interest in increasing living donation rates at centers trained in this method of transplantation. We examined a large socioeconomically heterogeneous cohort of patients listed for LT to identify recipient factors associated with living donation. We retrospectively reviewed 491 consecutive patients who were listed for LT at our center over a 24-month period. Demographic, medical, and socioeconomic data were extracted from electronic records and compared between those who had a potential living donor (LD) volunteer for assessment and those who did not; 245 patients (50%) had at least 1 potential LD volunteer for assessment. Multivariate logistic regression analysis identified that patients with a LD were more likely to have Child-Pugh C disease (odds ratio [OR], 2.44; P = 0.02), and less likely to be older (OR, 0.96; P = 0.002), single (OR, 0.34; P = 0.006), divorced (OR, 0.53; P = 0.03), immigrants (OR, 0.38; P = 0.049), or from the lowest income quintile (OR, 0.44; P = 0.02). In conclusion, this analysis has identified several factors associated with access to living donation. More research is warranted to define and overcome barriers to living donor liver transplantation through targeted interventions in underrepresented populations.

High preoperative bilirubin values protect against reperfusion injury after live donor liver transplantation.

Heme Oxygenase-1 and its product biliverdin/bilirubin have been demonstrated to protect against ischemia/reperfusion injury (IRI). We investigated whether increased preoperative bilirubin values of transplant recipients decrease IRI. Preoperative bilirubin levels of live donor liver recipients were correlated to postoperative liver transaminase as a marker of IRI. Additionally, two recipient groups with pretransplant bilirubin levels >24 µmol/l (n = 348) and ≤24 µmol/l (n = 118) were compared. Post-transplant liver function, complications, length of hospital stay, and patient and graft survival were assessed. Preoperative bilirubin levels were negatively correlated to the postoperative increase in transaminases suggesting a protective effect against IRI. The maximal rise of ALT after transplantation in high versus low bilirubin patients was 288 (-210-2457) U/l vs. 375 (-11-2102) U/l, P = 0.006. Bilirubin remained a significant determining factor in a multivariate linear regression analysis. The MELD score and its individual components as a marker of severity of chronic liver disease were significantly higher in the high versus low bilirubin group (P < 0.001). Despite this, overall complication rate (21.0% vs. 21.2%, P = 0.88), hospital stay [13 (4-260) vs. 14 (6-313) days, P = 0.93), and 1-year graft survival (90.8% vs. 89.0%, P = 0.62) were similar in both groups. High bilirubin levels of liver recipients before live donor transplantation is associated with decreased postoperative IRI.

Making sense of regulatory T cell suppressive function.

Several types of regulatory T cells maintain self-tolerance and control excessive immune responses to foreign antigens. The major regulatory T subsets described over the past decade and novel function in transplantation will be covered in this review with a focus on CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cells. Multiple mechanisms have been proposed to explain how Treg cells inhibit effector cells but none can completely explain the observed effects in toto. Proposed mechanisms to explain suppressive activity of Treg cells include the generation of inhibitory cytokines, induced death of effector cells by cytokine deprivation or cytolysis, local metabolic perturbation of target cells mediated by changes in extracellular nucleotide/nucleoside fluxes with alterations in intracellular signaling molecules such as cyclic AMP, and finally inhibition of dendritic cell functions. A better understanding of how Treg cells operate at the molecular level could result in novel and safer therapeutic approaches in transplantation and immune-mediated diseases.