Lymphotoxin ß receptor and tertiary lymphoid organs shape acute and chronic allograft rejection.

Solid organ transplantation remains the life-saving treatment for end-stage organ failure, but chronic rejection remains a major obstacle to long-term allograft outcomes and has not improved substantially. Tertiary lymphoid organs (TLO) are ectopic lymphoid structures that form under conditions of chronic inflammation, and evidence from human transplantation suggests that TLO regularly form in allografts undergoing chronic rejection. In this study, we utilized a mouse renal transplantation model and manipulation of the lymphotoxin alpha (LTα) - lymphotoxin beta receptor (LTßR) pathway, which is essential for TLO formation, to define the role of TLO in transplantation. We showed that intragraft TLO are sufficient to activate the alloimmune response and mediate graft rejection in a model where the only lymphoid organs are TLO in the allograft. When transplanted to recipients with a normal set of secondary lymphoid organs, the presence of graft TLO or LTα overexpression accelerated rejection. If the LTßR pathway was disrupted in the donor graft, TLO formation was abrogated, and graft survival prolonged. Intravital microscopy of renal TLO demonstrated that local T and B cell activation in TLOs is similar to that observed in secondary lymphoid organs. In summary, we demonstrated that immune activation in TLO contributes to local immune responses, leading to earlier allograft failure. TLO and the LTαß-LTßR pathway are therefore prime targets to limit local immune responses and prevent allograft rejection. These findings are applicable to other diseases such as autoimmunity or tumors, where either limiting or boosting local immune responses is beneficial and improves disease outcomes.

Anesthetic Spread of Ultrasound-Guided Paraspinal Blocks in Video-Assisted Thoracoscopic Surgery: A Three-Dimensional Reconstruction Image Study.

BACKGROUND: Anesthetic spread of ultrasound-guided paraspinal blocks is still unknown. OBJECTIVES: To compare the drug diffusion qualities of intertransverse process block (ITPB) and erector spinae plane block (ESPB) in clinical practice. STUDY DESIGN: Prospective computed tomography (CT)-3-dimensional (3D) reconstruction image study. SETTING: Operation room in hospital. METHODS: Twenty patients undergoing thoracoscopic pulmonary wedge resection or segmentectomy were enrolled. These procedures require localization of pulmonary nodules using CT-guided needle puncture immediately before surgery. The patients were divided into 2 groups, each consisting of 10 patients. Group I underwent ITPB, while group E underwent ESPB. These interventions were performed 30 minutes before surgery using 20 mL of 0.25% bupivacaine with 2 mL iohexol. Sensory loss of the thoracic dermatomes was assessed using cold stimulation before general anesthesia. Patients' CT localization images were used for 3D reconstruction after surgery, and the diffusion of the drug in each cross-section of the CT images was evaluated. RESULTS: Three-dimensional imaging of the drug showed that in group E, drug diffusion was improved in the cephalocaudal area compared to group I (10 vs 4.5 segments). Drug diffusion in group I was improved anteriorly and laterally ([10/10, 100%] in the paravertebral and intercostal spaces) and reached the front of the vertebral body along the thoracic fascia in certain segments (6/10, 60%). In group E, very few segments of the drug reached the paravertebral (2/10, 20%) and intercostal (3/10, 30%) spaces. All patients in group I had clear signs of loss of cold sensation on the lateral and anterior chest walls, with an average of 4 thoracic dermatomes. In group E, 3 patients had definite lateral and anterior chest wall cold stimulation signs, the thoracic dermatome was discontinuous, and the effect was only present between 1-2 segments. The blocking effect of the paraspinal zone was excellent (100%) in both groups. LIMITATIONS: However, this study has some limitations. First, the sample size was small, and clinical trials with larger samples are required to further verify the effects of ITPB and ESPB. Second, the same local anesthetic drug concentration and volume were used for both techniques in this study, and the effect of volume or concentration on drug diffusion was not further explored. CONCLUSIONS: Compared with ESPB, ITPB yielded increased stability in lateral and anterior chest wall block with improved anterior and intercostal spread, but reduced cephalocaudal spread.

A modified perioperative regimen for deceased donor kidney transplantation in presensitized recipients without prior desensitization therapy.

Background: Renal transplantation in HLA-presensitized recipients entails an increased risk of antibody-mediated rejection (AMR) and graft loss. There is currently no accepted standard treatment protocol that can help transplant surgeons safely perform deceased donor (DD) kidney transplantation in presensitized patients without pretransplant desensitization. Methods: Fifty-one panel-reactive antibody (PRA)-positive recipients and 62 PRA-negative retransplant recipients (control) who received DD renal transplantation were included. Patients in the presensitized group (donor-specific antibody [DSA]-positive, n=25; DSA-negative, n=26) without desensitization received a modified perioperative treatment starting on day 0 or -1 with rituximab, thymoglobulin, and low daily doses of intravenous immunoglobulin (IVIG, 10-20 g/d, for 14 days). Plasmapheresis was performed once before surgery in DSA-positive recipients. Results: The median follow-up time was 51 months in the presensitized group and 41 months in the control group. The incidence of early acute rejection (AR) and AMR (including mixed rejection) was 35.3% and 13.7% in the presensitized group, respectively, significantly higher than in the control group (14.5% and 1.6%, respectively). Within the presensitized group, the DSA-positive subgroup had more AMR than the DSA-negative subgroup (24.0% vs. 3.8%), but the incidence of T cell-mediated rejection was comparable (20.0% vs. 23.4%). In the presensitized group, all rejections were successfully reversed, and graft function remained stable during follow-up. The 1-year and 3-year survival rates of the grafts and recipients in this group were 98.0%. Conclusion: With a modified IVIG-based perioperative regimen, excellent intermediate-term graft and recipient survival outcomes can be achieved in presensitized patients who received DD kidney transplantation without prior desensitization.

Tissue-resident memory T cell maintenance during antigen persistence requires both cognate antigen and interleukin-15.

Our understanding of tissue-resident memory T (TRM) cell biology has been largely developed from acute infection models in which antigen is cleared and sterilizing immunity is achieved. Less is known about TRM cells in the context of chronic antigen persistence and inflammation. We investigated factors that underlie TRM maintenance in a kidney transplantation model in which TRM cells drive rejection. In contrast to acute infection, we found that TRM cells declined markedly in the absence of cognate antigen, antigen presentation, or antigen sensing by the T cells. Depletion of graft-infiltrating dendritic cells or interruption of antigen presentation after TRM cells were established was sufficient to disrupt TRM maintenance and reduce allograft pathology. Likewise, removal of IL-15 transpresentation or of the IL-15 receptor on T cells during TRM maintenance led to a decline in TRM cells, and IL-15 receptor blockade prevented chronic rejection. Therefore, antigen and IL-15 presented by dendritic cells play nonredundant key roles in CD8 TRM cell maintenance in settings of antigen persistence and inflammation. These findings provide insights that could lead to improved treatment of chronic transplant rejection and autoimmunity.

Can Kunxian Capsule, a Novel Tripterygium Preparation be Used as an Adjuvant Treatment of Early Recurrent Focal Segmental Glomerular Sclerosis After Renal Transplantation? A Case Report.

Focal segmental glomerular sclerosis (FSGS) tends to recur after kidney transplantation, particularly when genetic testing is negative. Once the recurrence happens, the renal graft function can rapidly become impaired, following a massive urine protein loss. Despite intensive plasmapheresis and high-dose rituximab treatment, the complete remission rate remains below 50%. The Kunxian capsule, representing a new generation of tripterygium preparation, has shown promising results in controlling proteinuria in patients with IgA nephropathy. It is unclear whether Kunxian capsule treatment would also produce a favorable response in cases of FSGS recurrence. Here we report favorable results with this approach in a patient with early recurrent FSGS after kidney transplantation; we treated this patient successfully with a Kunxian capsule, a low dose of rituximab (200 mg), and reduced sessions of plasmapheresis. Complete remission, with a 90% reduction in total urine protein (0.81 g/24 h vs 8.3 g/24 h), was achieved within 2 weeks post-treatment. Of interest, the complete remission state in this patient has been maintained over 20 months with continuous administration of Kunxian capsules after the cessation of plasmapheresis. The potential mechanisms involved here include direct podocyte protection and the anti-inflammatory and immunosuppressive properties of triptolide in the Kunxian capsule. Our case may offer a new reference option for treating recurrent FSGS in the future.

Identification and Verification of Potential Biomarkers in Renal Ischemia-Reperfusion Injury by Integrated Bioinformatic Analysis.

Background: Renal ischemia-reperfusion injury (RIRI) plays an important role in the poor prognosis of patients with renal transplants. However, the potential targets and mechanism of IRI are still unclear. Method: Differential gene expression (DEG) analysis and weighted correlation network analysis (WGCNA) were performed on the GSE27274 dataset. Pathway enrichment analysis on the DEGs was performed. To identify the hub DEGs, we constructed a protein-protein interaction (PPI) network. Finally, the hub genes were verified, and candidate drugs were screened from the DsigDB database. Results: A hundred DEGs and four hub genes (Atf3, Psmb6, Psmb8, and Psmb10) were screened out. Pathway enrichment analysis revealed that 100 DEGs were mainly enriched in apoptosis and the TNF signaling pathway. The four hub genes were verified in animal models and another dataset (GSE148420). Thereafter, a PPI network was used to identify the four hub genes (Atf3, Psmb6, Psmb8, and Psmb10). Finally, eight candidate drugs were identified as potential drugs. Conclusion: Three hub genes (Psmb6, Psmb8, and Psmb10) were associated with RIRI and could be potential novel biomarkers for RIRI.

Graft-versus-host disease is locally maintained in target tissues by resident progenitor-like T cells.

In allogeneic hematopoietic stem cell transplantation, donor αß T cells attack recipient tissues, causing graft-versus-host disease (GVHD), a major cause of morbidity and mortality. A central question has been how GVHD is sustained despite T cell exhaustion from chronic antigen stimulation. The current model for GVHD holds that disease is maintained through the continued recruitment of alloreactive effectors from blood into affected tissues. Here, we show, using multiple approaches including parabiosis of mice with GVHD, that GVHD is instead primarily maintained locally within diseased tissues. By tracking 1,203 alloreactive T cell clones, we fitted a mathematical model predicting that within each tissue a small number of progenitor T cells maintain a larger effector pool. Consistent with this, we identified a tissue-resident TCF-1+ subpopulation that preferentially engrafted, expanded, and differentiated into effectors upon adoptive transfer. These results suggest that therapies targeting affected tissues and progenitor T cells within them would be effective.

Bioinformatics analysis of immune-related prognostic genes and immunotherapy in renal clear cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is an immunogenic tumor, and investigating the immunorelated genes is essential. To investigate the immunoprognostic genes of ccRCC, we analyzed the data assimilated from a public database (The Cancer Genome Atlas (TCGA) database and the gene expression omnibus (GEO) database) using bioinformatics. Then, an immunoprognosis model was constructed to identify four hub genes with moderate predictive values for the prognosis of ccRCC patients. These four genes were associated with the prognosis of ccRCC patients based on Oncomine and Gena Expression Profiling Interactive Analysis (GEPIA) databases. The correlation analysis between the immune infiltrate, immune checkpoints, and immunotherapy and this immunoprognosis model showed that immune infiltration could predict the immunotherapy effects. We also conducted a quantitative real-time polymerase chain reaction analysis and found that the expressions of three hub genes were associated with tumor progression (P<0.1). In conclusion, four genes that may serve as potential biomarkers in ccRCC were identified with respect to prognosis.

Case Report: Successful ABO-Incompatible Deceased Donor Kidney Transplantation in an Infant Without Pre-transplant Immunological Treatment.

ABO blood group antibodies have not been generated or are at low titer during early infancy. Therefore, in theory, ABO-incompatible kidney transplantation (ABOi KT) may be successfully achieved in small infants without any pre-transplant treatment. We report here the first ABO-incompatible deceased donor kidney transplantation (ABOi DDKT) in an infant. The recipient infant was ABO blood group O, and the donor group A. The recipient was diagnosed with a Wilms tumor gene 1 (WT1) mutation and had received peritoneal dialysis for 4 months prior to transplant. At 7 months and 27 days of age, the infant underwent bilateral native nephrectomy and single-kidney transplantation from a 3-year-old brain-dead donor. No pre- or post-transplantation antibody removal treatment was performed, since the recipient's anti-iso-hemagglutinin-A Ig-M/G antibody titers were both low (1:2) before transplantation and have remained at low levels or undetectable to date. At 11 months post-transplant, the recipient is at home, thriving, with normal development and graft function. This outcome suggests that ABOi DDKT without antibody removal preparatory treatment is feasible in small infants, providing a new option for kidney transplantation in this age range.

Case report: Daratumumab for treatment of refractory late or chronic active antibody-mediated rejection in renal allograft recipients with high levels of de novo donor-specific antibodies.

Background: Late or chronic active antibody-mediated rejection (AMR) associated with de novo donor-specific antibodies (dnDSA) after renal transplantation is a great clinical challenge because it is often resistant to conventional therapies. Daratumumab, an anti-CD38 monoclonal antibody that can deplete plasma cells, may be effective for the treatment of late or chronic active AMR. Methods: We designed a novel regimen that included early intensive therapy with daratumumab plus plasmapheresis (PP)/intravenous immunoglobulins (IVIG) and later maintenance therapy with daratumumab alone, and used this regimen to treat late or chronic active AMR in two kidney transplant recipients with extremely high levels of anti-DQ7 dnDSA. Results: Both patients had a limited clinical response to the early treatment with rituximab and PP/IVIG (with or without splenic irradiation); however, they had a remarkable decrease in anti-DQ7 DSA (MFI value from ~20,000 to ~5,000) after 2-3 months of intensive therapy with daratumumab plus PP/IVIG. Over 20 months of follow-up, patient 1 maintained a low DSA (as low as 1,572) and normal renal function on daratumumab maintenance therapy. Patient 2 retained a low DSA and improved renal function and pathological lesions within one year after treatment but then deteriorated because of acute T cell-mediated rejection. Conclusions: Our daratumumab-based regimen has shown promising results in the treatment of refractory late active or chronic active AMR in renal transplant recipients with high-level dnDSA. This may provide a reference for better use of daratumumab in the treatment of late or chronic active AMR.

LncRNA H19 secreted by umbilical cord blood mesenchymal stem cells through microRNA-29a-3p/FOS axis for central sensitization of pain in advanced osteoarthritis.

OBJECTIVE: To explore the molecular mechanism of umbilical cord blood mesenchymal stem cells (UCBMSCs) in the treatment of advanced osteoarthritis pain. METHODS: Normal healthy rats were selected to establish advanced osteoarthritis (OA) model, and the rats were randomly divided into control group, intravenous group, intracavitary group and intrathecal group. The intravenous group received intravenous injection of UCBMSCs, intracavitary group received intra-articular injection of UCBMSCs, and intrathecal group received subarachnoid injection of UCBMSCs. The pain behavior and serum pro-inflammatory factor levels were evaluated before and after treatment. microRNA-29a-3p and FOS mRNA in spinal dorsal horn was detected using qPCR, the phosphorylation of c-fos protein and NR1, NR2B, ERK and PKCg was detected using Western blot, and the level of LncRNA H19 was detected using qPCR. RESULTS: LncRNA H19 was enriched in the exosomes of UCBMSCs. microRNA-29a-3p was the target gene of LncRNA H19, while FOS was the downstream target of microRNA-29a-3p. Pain and inflammation of rats in the intrathecal group improved best, and the phosphorylation levels of c-fos and NR1, NR2B, ERK and PKCg in the spinal dorsal horn of the intrathecal group decreased. LncRNA H19 regulated the central sensitization of astrocytes through microRNA-29a-3p/FOS axis. CONCLUSION: Intrathecal injection of umbilical cord blood mesenchymal stem cells can improve the pain and central sensitization of advanced osteoarthritis through LncRNA H19/microRNA-29a-3p/FOS axis.

Chinese Association for the Study of Pain: Experts consensus on ultrasound-guided injections for the treatment of spinal pain in China (2020 edition).

Spinal pain (SP) is a common condition that has a major negative impact on a patient's quality of life. Recent developments in ultrasound-guided injections for the treatment of SP are increasingly being used in clinical practice. This clinical expert consensus describes the purpose, significance, implementation methods, indications, contraindications, and techniques of ultrasound-guided injections. This consensus offers a practical reference point for physicians to implement successfully ultrasound-guided injections in the treatment of chronic SP.

Resident memory T cells form during persistent antigen exposure leading to allograft rejection.

Tissue-resident memory T cells (TRM) contained at sites of previous infection provide local protection against reinfection. Whether they form and function in organ transplants where cognate antigen persists is unclear. This is a key question in transplantation as T cells are detected long term in allografts, but it is not known whether they are exhausted or are functional memory T cells. Using a mouse model of kidney transplantation, we showed that antigen-specific and polyclonal effector T cells differentiated in the graft into TRM and subsequently caused allograft rejection. TRM identity was established by surface phenotype, transcriptional profile, and inability to recirculate in parabiosis and retransplantation experiments. Graft TRM proliferated locally, produced interferon-γ upon restimulation, and their in vivo depletion attenuated rejection. The vast majority of antigen-specific and polyclonal TRM lacked phenotypic and transcriptional exhaustion markers. Single-cell analysis of graft T cells early and late after transplantation identified a transcriptional program associated with transition to the tissue-resident state that could serve as a platform for the discovery of therapeutic targets. Thus, recipient effector T cells differentiate into functional graft TRM that maintain rejection locally. Targeting these TRM could improve renal transplant outcomes.

Ultrasound-guided anterior iliopsoas muscle space block versus posterior lumbar plexus block in hip surgery in the elderly: A randomised controlled trial.

BACKGROUND: Ultrasound-guided posterior lumbar plexus block is widely used for hip fracture surgery but it requires a change of position, which may be painful. OBJECTIVES: Our primary objective was to describe a new technique, the anterior iliopsoas muscle space block, which can be performed in the supine position, and to test the hypothesis that its analgesia for hip surgery was similar to that of the traditional posterior lumbar plexus block. DESIGN: Randomised, double-blind study. SETTING: Shanghai 6th People's Hospital, China, from February to August 2019. PATIENTS: Forty-eight patients scheduled for unilateral hip fracture surgery were included in the study. The exclusion criteria were infection at the puncture site, history of hip surgery, pre-existing neurological deficits of the lower extremity, contraindications for regional anaesthesia, allergy to local anaesthetics, coagulopathy, abuse of medicine or alcohol, or daily consumption of analgesics. INTERVENTIONS: Patients were randomised to receive a lateral sacral plexus block with either an anterior iliopsoas muscle space block or a posterior lumbar plexus block, using 0.33% ropivacaine (30 ml each). MAIN OUTCOME MEASURES: The main outcome was verbal numerical scale (VNS) pain intensity 1 h after surgery in the postanesthesia care unit, and the secondary outcome was the dose of intra-operative fentanyl. The differences in VNS scores and fentanyl use between the groups were analysed. RESULTS: Based on previous work, we considered a difference (confidence interval [CI]) of 1.6 on the VNS to be significant. The median [IQR] pain scores in postanesthesia care unit were similar in the anterior 0 [0 to 3] and posterior groups 1.5 [0 to 3]. The median scores for intra-operative fentanyl use were similar in the anterior 20 [10 to 42.5] µg and posterior groups 15 [0 to 50] µg (P = 0.34). The difference in the median pain score at-rest was NS: anterior group 0.5 [0 to 5], posterior group 0 [0 to 2], median difference -0.5 (95% CI -2 to 0). The median post to preblock difference in VNS was higher in the anterior -0.5 [-2 to 0] than in the posterior group 0 [-1.25 to 0], median difference 0.5 (95% CI 0 to 1). The median block onset time was longer in the anterior 11 [6 to 14.25] min than in the posterior group 6 [4.75 to 8] min (P = 0.002), median difference -5 (95% CI -7 to -1). CONCLUSION: The anterior iliopsoas muscle space block had the same effect as the posterior lumbar plexus block on peri-operative analgesia for hip surgery, but with a longer onset time. Therefore, anterior iliopsoas muscle space block can be recommended as a routine technique for hip and lower limb procedures. TRIAL REGISTRATION: http://www.chictr.org.cn identifier: ChiCTR1900021214.

Soluble epoxide hydrolase deficiency attenuates lipotoxic cardiomyopathy via upregulation of AMPK-mTORC mediated autophagy.

Obesity-driven cardiac lipid accumulation can progress to lipotoxic cardiomyopathy. Soluble epoxide hydrolase (sEH) is the major enzyme that metabolizes epoxyeicosatrienoic acids (EETs), which have biological activity of regulating lipid metabolism. The current study explores the unknown role of sEH deficiency in lipotoxic cardiomyopathy and its underlying mechanism. Wild-type and Ephx2 knock out (sEH KO) C57BL/6 J mice were fed with high-fat diet (HFD) for 24 weeks to induce lipotoxic cardiomyopathy animal models. Palmitic acid (PA) was utilized to induce lipotoxicity to cardiomyocytes for in vitro study. We found sEH KO, independent of plasma lipid and blood pressures, significantly attenuated HFD-induced myocardial lipid accumulation and cardiac dysfunction in vivo. HFD-induced lipotoxic cardiomyopathy and dysfunction of adenosine 5'-monophosphate-activated protein kinase-mammalian target of rapamycin complex (AMPK-mTORC) signaling mediated lipid autophagy in heart were restored by sEH KO. In primary neonatal mouse cardiomyocytes, both sEH KO and sEH substrate EETs plus sEH inhibitor AUDA treatments attenuated PA-induced lipid accumulation. These effects were blocked by inhibition of AMPK or autophagy. The outcomes were supported by the results that sEH KO and EETs plus AUDA rescued HFD- and PA-induced impairment of autophagy upstream signaling of AMPK-mTORC, respectively. These findings revealed that sEH deficiency played an important role in attenuating myocardial lipid accumulation and provided new insights into treating lipotoxic cardiomyopathy. Regulation of autophagy via AMPK-mTORC signaling pathway is one of the underlying mechanisms.

Carbamylated erythropoietin regulates immune responses and promotes long-term kidney allograft survival through activation of PI3K/AKT signaling.

Modulation of alloimmune responses is critical to improving transplant outcome and promoting long-term graft survival. To determine mechanisms by which a nonhematopoietic erythropoietin (EPO) derivative, carbamylated EPO (CEPO), regulates innate and adaptive immune cells and affects renal allograft survival, we utilized a rat model of fully MHC-mismatched kidney transplantation. CEPO administration markedly extended the survival time of kidney allografts compared with the transplant alone control group. This therapeutic effect was inhibited when the recipients were given LY294002, a selective inhibitor of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway or anti-EPO receptor (EPOR) antibody, in addition to CEPO. In vitro, CEPO inhibited the differentiation and function of dendritic cells and modulated their production of pro-inflammatory and anti-inflammatory cytokines, along with activating the PI3K/AKT signaling pathway and increasing EPOR mRNA and protein expression by these innate immune cells. Moreover, after CD4+ T cells were exposed to CEPO the Th1/Th2 ratio decreased and the regulatory T cell (Treg)/Th17 ratio increased. These effects were abolished by LY294002 or anti-EPOR antibody, suggesting that CEPO regulates immune responses and promotes kidney allograft survival by activating the PI3K/AKT signaling pathway in an EPOR-dependent manner. The immunomodulatory and specific signaling pathway effects of CEPO identified in this study suggest a potential therapeutic approach to promoting kidney transplant survival.

Innate Allorecognition and Memory in Transplantation.

Over the past few decades, we have witnessed a decline in the rates of acute rejection without significant improvement in chronic rejection. Current treatment strategies principally target the adaptive immune response and not the innate response. Therefore, better understanding of innate immunity in transplantation and how to target it is highly desirable. Here, we review the latest advances in innate immunity in transplantation focusing on the roles and mechanisms of innate allorecognition and memory in myeloid cells. These novel concepts could explain why alloimmune response do not abate over time and shed light on new molecular pathways that can be interrupted to prevent or treat chronic rejection.

PIRs mediate innate myeloid cell memory to nonself MHC molecules.

Immunological memory specific to previously encountered antigens is a cardinal feature of adaptive lymphoid cells. However, it is unknown whether innate myeloid cells retain memory of prior antigenic stimulation and respond to it more vigorously on subsequent encounters. In this work, we show that murine monocytes and macrophages acquire memory specific to major histocompatibility complex I (MHC-I) antigens, and we identify A-type paired immunoglobulin-like receptors (PIR-As) as the MHC-I receptors necessary for the memory response. We demonstrate that deleting PIR-A in the recipient or blocking PIR-A binding to donor MHC-I molecules blocks memory and attenuates kidney and heart allograft rejection. Thus, innate myeloid cells acquire alloantigen-specific memory that can be targeted to improve transplant outcomes.