Spatial map of human T cell compartmentalization and maintenance over decades of life.

Mechanisms for human memory T cell differentiation and maintenance have largely been inferred from studies of peripheral blood, though the majority of T cells are found in lymphoid and mucosal sites. We present here a multidimensional, quantitative analysis of human T cell compartmentalization and maintenance over six decades of life in blood, lymphoid, and mucosal tissues obtained from 56 individual organ donors. Our results reveal that the distribution and tissue residence of naive, central, and effector memory, and terminal effector subsets is contingent on both their differentiation state and tissue localization. Moreover, T cell homeostasis driven by cytokine or TCR-mediated signals is different in CD4+ or CD8+ T cell lineages, varies with their differentiation stage and tissue localization, and cannot be inferred from blood. Our data provide an unprecedented spatial and temporal map of human T cell compartmentalization and maintenance, supporting distinct pathways for human T cell fate determination and homeostasis.

Partial bladder transplantation with en bloc kidney transplant-long-term, 17 years, the outcome of a "bladder patch technique".

A transplant of a portion of the bladder with an en bloc kidney from a 2-year-old donor was previously reported in a 12-month-old girl due to her extremely small bladder. Bilateral kidneys were transplanted en bloc with their ureters connected to a patch of the donor bladder (bladder patch technique). The long-term outcomes and complications of this technique have not been documented. Here, we report a long-term, 17-year follow-up of this patient with an evaluation of whole bladder functions at 18 years of age. The patient has had no episodes of urinary tract infections. Cystoscopy showed a viable transplanted bladder with a well-perfused mucosa. We observed that the native bladder has stretched over time, forming more than half of the bladder wall. Urodynamic studies showed preserved bladder compliance at 43 mL/cmH2O, and native bladder contractility was preserved. Prolonged voiding time and postvoid residual urine were also observed. These findings were suggestive of detrusor underactivity. No reflux across the donor ureterovesical junctions was observed. The recipient was instructed to continue timed voiding and double voiding to empty the bladder. In conclusion, en bloc kidney transplantation with a bladder patch is a feasible and safe option for kidney transplant recipients with a small bladder capacity.

An appraisal of technical variant grafts compared to whole liver grafts in pediatric liver transplant recipients: Multicenter analysis from the SPLIT registry.

BACKGROUND: Shortages of liver allografts for children awaiting transplantation have led to high LT waitlist mortality. Prior studies have shown that usage of TVG can reduce waiting time and waitlist mortality, but their use is not universal. We sought to compare patient and graft survival between WLG and TVG and to identify potential associated risk factors in a contemporary pediatric LT cohort. METHODS: We performed a retrospective analysis of patient survival, graft survival, and biliary and vascular complications for LT recipients <18 years old entered into the Society of Pediatric Liver Transplantation prospective multicenter database. RESULTS: Of 1839 LT recipients, 1029 received a WLG and 810 received a TVG from either a LD or a DD. There was no difference in patient survival or graft survival by graft type. Three-year patient survival and graft survival were 96%, 93%, and 96%, and 95%, 89%, and 92% for TVG-LD, TVG-DD, and WLG, respectively. Biliary complications were more frequent in TVG. Hepatic artery thrombosis was more frequent in WLG. Multivariate analysis revealed primary diagnosis was the only significant predictor of patient survival. Predictors for graft survival included time-dependent development of biliary and vascular complications. CONCLUSIONS: There were no significant differences in patient and graft survival based on graft types in this North American multi-center pediatric cohort. Widespread routine use of TVG should be strongly encouraged to decrease mortality on the waitlist for pediatric LT candidates.

Ex Vivo Liver Resection and Autotransplantation: Should It be Used More Frequently?

OBJECTIVE: We herein advocate for more extensive utilization of ex vivo resection techniques for otherwise unresectable liver tumors by presenting the largest collective American experience. BACKGROUND: Advanced in situ resection and vascular reconstruction techniques have made R0 resection possible for otherwise unresectable liver tumors. Ex vivo liver resection may further expand the limits of resectability but remains underutilized due to concerns about technical complexity and vascular thrombosis. However, we believe that the skillset required for ex vivo liver resection is more widespread and the complications less severe than widely assumed, making ex vivo resection a more attractive option in selected case. METHODS: We retrospectively analyzed 35 cases performed by surgical teams experienced with ex vivo liver resections (at least 4 cases) between 1997 and 2021. RESULTS: We categorized malignancies as highly aggressive (n=18), moderately aggressive (n=14), and low grade (n=3). All patients underwent total hepatectomy, vascular reconstruction and resection in hypothermia on the backtable, and partial liver autotransplantation. Overall survival was 67%/39%/28%, at 1/3/5 years, respectively, with a median survival of 710 days (range: 22-4824). Patient survival for highly aggressive, moderately aggressive, and low-grade tumors was 61%/33%/23%, 67%/40%/22%, and 100%/100%/100% at 1/3/5 years, respectively, with median survival 577 days (range: 22-3873), 444 days (range: 22-4824), and 1825 days (range: 868-3549). CONCLUSIONS: Ex vivo resection utilizes techniques commonly practiced in partial liver transplantation, and we demonstrate relatively favorable outcomes in our large collective experience. Therefore, we propose that more liberal use of this technique may benefit selected patients in centers experienced with partial liver transplantation.

Distribution and compartmentalization of human circulating and tissue-resident memory T cell subsets.

Knowledge of human T cells derives chiefly from studies of peripheral blood, whereas their distribution and function in tissues remains largely unknown. Here, we present a unique analysis of human T cells in lymphoid and mucosal tissues obtained from individual organ donors, revealing tissue-intrinsic compartmentalization of naive, effector, and memory subsets conserved between diverse individuals. Effector memory CD4(+) T cells producing IL-2 predominated in mucosal tissues and accumulated as central memory subsets in lymphoid tissue, whereas CD8(+) T cells were maintained as naive subsets in lymphoid tissues and IFN-γ-producing effector memory CD8(+) T cells in mucosal sites. The T cell activation marker CD69 was constitutively expressed by memory T cells in all tissues, distinguishing them from circulating subsets, with mucosal memory T cells exhibiting additional distinct phenotypic and functional properties. Our results provide an assessment of human T cell compartmentalization as a new baseline for understanding human adaptive immunity.

Stable liver graft post anti-PD1 therapy as a bridge to transplantation in an adolescent with hepatocellular carcinoma.

BACKGROUND: Immunotherapy, specifically immune checkpoint inhibitors (ICIs), including anti-programmed cell death 1 (anti-PD1), has recently received clinical approval for the treatment of adult hepatocellular carcinoma (HCC). However, the safety and efficacy of ICIs prior to solid organ transplant are unknown, especially in pediatrics. Safety reports are variable in adults, with some series describing subsequent allograft rejection and loss while others report successful transplants without allograft rejection.As ICIs stimulate the immune system by blocking the interaction between PD1 and the ligand-receptor pair programmed cell death-ligand 1 (PDL1), the downstream effects of T-cell activation increase the risk of graft rejection. METHODS: Here, we present a case of an adolescent with moderately differentiated non-fibrolamellar HCC treated with pembrolizumab, an anti-PD1 therapy, who subsequently underwent successful orthotopic liver transplantation (OLT). RESULTS: Our patient received an OLT 138 days from the last pembrolizumab dose with graft preservation. The patient has no evidence of recurrent disease or any episode of allograft rejection 48 months post OLT. Staining of tumor and normal tissues from longitudinal specimens finds PDL1 positive Kupffer cells present in normal liver and peritumoral areas with no changes post anti-PD1 therapy. In contrast, tumor cells were negative for PDL1. CONCLUSION: This case represents a basis for optimism in potential use of anti-PD1 therapy in liver transplant candidates and supports further investigation of immune checkpoint inhibitors use in this unique patient population.

Heterochromatin protein 1γ deficiency decreases histone H3K27 methylation in mouse neurosphere neuronal genes.

Heterochromatin protein (HP) 1γ, a component of heterochromatin in eukaryotes, is involved in H3K9 methylation. Although HP1γ is expressed strongly in neural tissues and neural stem cells, its functions are unclear. To elucidate the roles of HP1γ, we analyzed HP1γ -deficient (HP1γ KO) mouse embryonic neurospheres and determined that HP1γ KO neurospheres tended to differentiate after quaternary culture. Several genes normally expressed in neuronal cells were upregulated in HP1γ KO undifferentiated neurospheres, but not in the wild type (WT). Compared to that in the control neurospheres, the occupancy of H3K27me3 was lower around the transcription start sites (TSSs) of these genes in HP1γ KO neurospheres, while H3K9me2/3, H3K4me3, and H3K27ac amounts remained unchanged. Moreover, amounts of the H3K27me2/3 demethylases, UTX, and JMJD3, were increased around the TSSs of these genes. Treatment with GSK-J4, an inhibitor of H3K27 demethylases, decreased the expression of genes upregulated in HP1γ KO neurospheres, along with an increase of H3K27me3 amounts. Therefore, in murine neurospheres, HP1γ protected the promoter sites of differentiated cell-specific genes against H3K27 demethylases to repress the expression of these genes. A better understanding of central cellular processes such as histone methylation will help elucidate critical events such as cell-specific gene expression, epigenetics, and differentiation.

Ex Vivo Resection and Autotransplantation for Conventionally Unresectable Tumors - An 11-year Single Center Experience.

BACKGROUND AND AIMS: Ex vivo surgery may provide a chance at R0 resection for conventionally unresectable tumors. However, long-term outcomes have not been well documented. In this study, we analyze our 11-year outcomes to define its role. STUDY DESIGN: We retrospectively analyzed 46 consecutive patients who underwent ex vivo surgery at our institution 2008-2019. RESULTS: The types of tumors were: carcinoma (n = 20), sarcoma (n = 20) and benign to low grade tumor (n = 6). The type of ex vivo surgery was chosen based on tumor location and vascular involvement. The most commonly performed procedure was ex vivo hepatectomy (n = 18), followed by ex vivo resection and intestinal autotransplantation (n = 12), ex vivo Whipple procedure and liver autotransplantation (n = 8) and multivisceral ex vivo procedure (n = 7). Twenty-three patients (50%) are currently alive with median follow-up of 4.0-years (11 months-11.8 years). The overall survival was 70%/59%/52%, at 1-/3-/5-years, respectively. Patient survival for benign to low grade tumors, sarcoma, and carcinoma was 100%/100%/100%, 65%/60%/50%, and 65%/45%/40%, at 1-/3-/5-years, respectively. Ninety-one percent patients had R0 resection, and 57% had no recurrence to date with median follow-up of 3.1-years. Two patients (4.3%) died within 30 days due to sepsis and gastroduodenal artety (GDA) stump blowout. Two additional patients died between 30 and 90 days due to sepsis. Perioperative mortality in the last 23 consecutive cases was limited to 1 patient who died of sepsis between 30 and 90 days. CONCLUSIONS: For a selected group of patients with conventionally unresectable tumors, ex vivo surgery can offer effective surgical removal with a reasonably low perioperative mortality at experienced centers.

A case of an Infant with SARS-CoV-2 hepatitis early after liver transplantation.

We present a case of a pediatric liver transplant recipient diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection four days after receiving a living donor liver allograft from her mother. The recipient was a 6-month-old with end-stage liver disease due to biliary atresia and failed Kasai. The infant had an uncomplicated implantation, excellent graft function and down-trending liver enzymes until developing fevers, diarrhea, and moderate respiratory distress requiring non-invasive respiratory support. SARS-CoV-2 testing (nasal swab Polymerase Chain Reaction) was positive on post-operative day (POD) 4. Liver enzymes peaked ~1000 U/L (5-fold higher than the previous day) on POD 6. Histology demonstrated a mixed picture of moderate acute hepatitis and classical elements of mild to moderate acute cellular rejection. Her hepatitis and respiratory symptoms improved coincident with completing treatment with hydroxychloroquine, reduced immunosuppression, and intravenous gamma globulin (IVIG).

Ant1 mutant mice bridge the mitochondrial and serotonergic dysfunctions in bipolar disorder.

Although mitochondrial and serotonergic dysfunctions have been implicated in the etiology of bipolar disorder (BD), the relationship between these unrelated pathways has not been elucidated. A family of BD and chronic progressive external ophthalmoplegia (CPEO) caused by a mutation of the mitochondrial adenine nucleotide translocator 1 (ANT1, SLC25A4) implicated that ANT1 mutations confer a risk of BD. Here, we sequenced ANT1 in 324 probands of NIMH bipolar disorder pedigrees and identified two BD patients carrying heterozygous loss-of-function mutations. Behavioral analysis of brain specific Ant1 heterozygous conditional knockout (cKO) mice using lntelliCage showed a selective diminution in delay discounting. Delay discounting is the choice of smaller but immediate reward than larger but delayed reward and an index of impulsivity. Diminution of delay discounting suggests an increase in serotonergic activity. This finding was replicated by a 5-choice serial reaction time test. An anatomical screen showed accumulation of COX (cytochrome c oxidase) negative cells in dorsal raphe. Dorsal raphe neurons in the heterozygous cKO showed hyperexcitability, along with enhanced serotonin turnover in the nucleus accumbens and upregulation of Maob in dorsal raphe. These findings altogether suggest that mitochondrial dysfunction as the genetic risk of BD may cause vulnerability to BD by altering serotonergic neurotransmission.

Reduction behaviors of permanganate by microbial cells and concomitant accumulation of divalent cations of Mg2+, Zn2+, and Co2.

Permanganate treatment is widely used for disinfection of bacteria in surface-contaminated water. In this paper, the fate of the dissolved permanganate in aqueous solution after contact with cells of Pseudomonas fluorescens was studied. Concomitant accumulation of divalent cations of Mg2+, Zn2+, and Co2+ during precipitation of Mn oxides was also studied. The time course of the Mn concentration in solution showed an abrupt decrease after contact of Mn(VII) with microbial cells, followed by an increase after ~24 hr. XRD analysis of the precipitated Mn oxides, called biomass Mn oxides, showed the formation of low-crystalline birnessite. Visible spectroscopy and X-ray absorption near edge structure (XANES) analyses indicated that dissolved Mn(VII) was reduced to form biomass Mn oxides involving Mn(IV) and Mn(III), followed by reduction to soluble Mn(II). The numbers of electron transferred from microbial cells to permanganate and to biomass Mn oxides for 24 hr after the contact indicated that the numbers of electron transfer from microbial cell was approximately 50 times higher to dissolved permanganate than to the biomass Mn oxides in present experimental conditions. The 24 hr accumulation of divalent cations during formation of biomass Mn oxides was in the order of Co2+ > Zn2+ > Mg2+. XANES analysis of Co showed that oxidation of Co2+ to Co3+ resulted in higher accumulation of Co than Zn and Mg. Thus, treatment of surface water by KMnO4 solution is effective not only for disinfection of microorganisms, but also for the elimination of metal cations from surface water.

Pure Laparoscopic Donor Hepatectomies: Ready for Widespread Adoption?

OBJECTIVE: In order to minimize the impact of donation, fully laparoscopic donor hepatectomy (LDH) is being investigated at a few centers throughout the world. We report here our experience with 51 living donor pure laparoscopic hepatectomies. BACKGROUND: Adoption of minimal access techniques to living donor liver transplantation (LDLT) has been slowed by concerns about donor safety and the quality of the grafts. METHODS: Of 344 donor hepatectomies (DHs) for living donor liver transplantation (LDLT) since 1998, 51 pure LDH have been performed since 2009. We report here our experience with 51 living donor pure laparoscopic hepatectomy (LH), based on prospectively collected data. There were 31 left lateral sectionectomy and 20 full lobectomies LH. We matched full lobe LH to open DH prior to introduction of LH. RESULTS: LH increased from 21% of all DH in first 5 years of performing LH to 45% of DH in the most recent 3 years. Laparoscopic donors were more likely female, had lower body mass index, smaller total livers, and smaller allografts but longer operating room times. In the total LD experience, total 5 donors were converted to open surgery (10%), 2 donors required transfusion (4%), and there was 2 donor bile leaks (4%). Recipient patient and graft 1-year survival was 98% and 94%. CONCLUSIONS: Our experience indicates that LDH for LDLT can be safely used with appropriate attention to learning curve and progression from left lateral sectionectomy to right hepatectomy.

Liver atrophy and regeneration in noncirrhotic portal vein thrombosis: Effect of surgical shunts.

The goal of the study is to characterize the relationship between portal vein thrombosis (PVT) and hepatic atrophy in patients without cirrhosis and the effect of various types of surgical shunts on liver regeneration and splenomegaly. Patients without cirrhosis with PVT suffer from presinusoidal portal hypertension, and often hepatic atrophy is a topic that has received little attention. We hypothesized that patients with PVT have decreased liver volumes, and shunts that preserve intrahepatic portal flow enhance liver regeneration. Sixty-four adult and pediatric patients with PVT who underwent surgical shunt placement between 1998 and 2011 were included in a retrospective study. Baseline liver volumes from adult patients were compared with standard liver volume (SLV) as well as a group of healthy controls undergoing evaluation for liver donation. Clinical assessment, liver function tests, and liver and spleen volumes from cross-sectional imaging were compared before and after surgery. A total of 40 patients received portal flow-preserving shunts (32 mesoportal and 8 selective splenorenal), whereas 24 received portal flow-diverting shunts (16 nonselective splenorenal and 8 mesocaval). Baseline adult liver volumes were 26% smaller than SLV (1248 versus 1624 cm3 ; P = 0.02) and 20% smaller than the control volumes (1248 versus 1552 cm3 ; P = 0.02). Baseline adult spleen volumes were larger compared with controls (1258 versus 229 cm3 ; P < 0.001). Preserving shunts were associated with significant increase in liver volumes (886 versus 1131 cm3 ; P = 0.01), whereas diverting shunts were not. Diverting shunts significantly improved splenomegaly. In conclusion, we have demonstrated that patients without cirrhosis with PVT have significant liver atrophy and splenomegaly. Significant liver regeneration was achieved after portal flow-preserving shunts. Liver Transplantation 24 881-887 2018 AASLD.

New insights into the role of Jmjd3 and Utx in axial skeletal formation in mice.

Jmjd3 and Utx are demethylases specific for lysine 27 of histone H3. Previous reports indicate that Jmjd3 is essential for differentiation of various cell types, such as macrophages and epidermal cells in mice, whereas Utx is involved in cancer and developmental diseases in humans and mice, as well as Hox regulation in zebrafish and nematodes. Here, we report that Jmjd3, but not Utx, is involved in axial skeletal formation in mice. A Jmjd3 mutant embryo (Jmjd3Δ18/Δ18), but not a catalytically inactive Utx truncation mutant (Utx-/y), showed anterior homeotic transformation. Quantitative RT-PCR and microarray analyses showed reduced Hox expression in both Jmjd3Δ18/Δ18 embryos and tailbuds, whereas levels of Hox activators, such as Wnt signaling factors and retinoic acid synthases, did not decrease, which suggests that Jmjd3 plays a regulatory role in Hox expression during axial patterning. Chromatin immunoprecipitation analyses of embryo tailbud tissue showed trimethylated lysine 27 on histone H3 to be at higher levels at the Hox loci in Jmjd3Δ18/Δ18 mutants compared with wild-type tailbuds. In contrast, trimethylated lysine 4 on histone H3 levels were found to be equivalent in wild-type and Jmjd3Δ18/Δ18 tailbuds. Demethylase-inactive Jmjd3 mutant embryos showed the same phenotype as Jmjd3Δ18/Δ18 mice. These results suggest that the demethylase activity of Jmjd3, but not that of Utx, affects mouse axial patterning in concert with alterations in Hox gene expression.-Naruse, C., Shibata, S., Tamura, M., Kawaguchi, T., Abe, K., Sugihara, K., Kato, T., Nishiuchi, T., Wakana, S., Ikawa, M., Asano, M. New insights into the role of Jmjd3 and Utx in axial skeletal formation in mice.

Recurrence After Liver Transplantation for Hepatocellular Carcinoma: A New MORAL to the Story.

OBJECTIVE: We sought to develop a "Model Of Recurrence After Liver transplant" (MORAL) for hepatocellular carcinoma (HCC). BACKGROUND: The Milan criteria are used to allocate livers to patients with HCC requiring liver transplantation (LT) but do not include objective measures of tumor biology. Biological markers including the neutrophil-lymphocyte ratio (NLR) and alpha-fetoprotein (AFP) have been associated with recurrence risk. METHODS: Prospective cohort study of adults undergoing LT for HCC between January 2001 and December 2012. RESULTS: A total of 339 patients were included. On multivariable Cox regression analysis, 3 preoperatively available factors were independent predictors of worse recurrence-free survival (RFS), namely, an NLR ≥ 5 (P < 0.0001, hazard ratio, HR: 6.2), AFP > 200 (P < 0.0001, HR: 3.8), and Size >3 cm (P < 0.001, HR: 3.2). The Pre-MORAL score was constructed from the hazard ratios and assigning patients points in an additive fashion, with a minimum of 0 points (no factors) and a maximum of 13 points (all 3 factors). The highest risk patients in the Pre-MORAL had a 5-year RFS of 17.9% compared with 98.6% for the low risk group (P < 0.0001). The post-MORAL was constructed similarly using the 4 postoperatively available independent predictors of worse RFS, grade 4 HCC's (P < 0.0001, HR: 5.6), vascular invasion (P = 0.019, HR: 2.0), size >3 cm (P < 0.0001, HR: 3.2) and number >3 (P = 0.048, HR: 1.8). The pre- and post-MORAL were superior to Milan at predicting recurrence with c-statistics of 0.82 and 0.87, compared with 0.63, respectively. We then combined the scores to produce a combo-MORAL, with a c-statistic of 0.91 for predicting recurrence. CONCLUSIONS: The MORAL score provides a simple, highly accurate tool for predicting recurrence and risk-stratification pre- and postoperatively.

Expanding the Margins: High Volume Utilization of Marginal Liver Grafts Among >2000 Liver Transplants at a Single Institution.

OBJECTIVE: Marginal livers (ML) have been used to expand the donor pool. National utilization of MLs is variable, and in some centers, they are never used. We examined the outcomes of MLs in the largest single center series of MLs used to date and compared outcomes to standard (SL) and living donor (LD) livers. METHODS: Analysis of a prospectively maintained database of all liver transplants performed at our institution from 1998 to 2016. ML grafts were defined as livers from donors >70, livers discarded regionally and shared nationally, livers with cold ischemic time >12 hours, livers from hepatitis C virus positive donors, livers from donation after cardiac death donors, livers with >30% steatosis, and livers split between 2 recipients. RESULTS: A total of 2050 liver transplant recipients were studied, of these 960 (46.8%) received ML grafts. ML recipients were more likely to have lower MELDs and have hepatocellular carcinoma. Most MLs used were from organs turned down regionally and shared nationally (69%) or donors >70 (22%). Survival of patients receiving MLs did not significantly differ from patients receiving SL grafts (P = 0.08). ML and SL recipients had worse survival than LDs (P < 0.01). Despite nearly half of our recipients receiving MLs, overall survival was significantly better than national survival over the same time period (P = 0.04). Waitlist mortality was significantly lower in our series compared with national results (19% vs 24.0%, P < 0.0001). CONCLUSIONS: Outcomes of recipients of ML grafts are comparable to SL transplants. Despite liberal use of these grafts, we have been able to successfully reduce waitlist mortality while exceeding national post-transplant survival metrics.

Leaning to the Left: Increasing the Donor Pool by Using the Left Lobe, Outcomes of the Largest Single-center North American Experience of Left Lobe Adult-to-adult Living Donor Liver Transplantation.

OBJECTIVE: Centers offering adult living donor liver transplantation (LDLT) mostly use right lobe grafts due to fears of providing recipients with insufficient hepatic volume, and the technical challenges presented by using left lobe grafts (LLGs). LLGs therefore represent approximately 5% of adult LDLTs performed in the United States. Here we present the largest North American experience with the use of LLG for adult LDLT. METHODS: Analysis of a prospectively maintained database of LDLTs performed from 1998 to 2015 at our institution. RESULTS: A total of 214 adult LDLTs were studied. Fifty-six patients (26%) received LLG. LLG recipients were more likely to be women, had significantly lower BMI, graft weight, and graft-weight-recipient-weight ratios (P < 0.05 for all). There were no significant differences in vascular or biliary complication between the groups. No significant differences existed in patient or graft survival at 1, 3, and 5 years (P = 0.747 and P = 0.398 respectively). Despite significantly increased risk of small-for-size syndrome in LLG, there was no increased risk of retransplant within 90-days or perioperative mortality in LLG recipients (P = 0.308 and P = 0.932 respectively). Graft type did not predict patient or graft outcomes on regression analysis (P = 0.857 and 0.399 respectively). CONCLUSIONS: Despite smaller graft sizes, outcomes of adult LDLT using LLG are comparable to right lobe grafts transplants. Left lobes can provide an important resource in an era of severe organ shortages, and these data should serve to allay the concerns of the transplant community in the United States.