Outcomes of kidney transplantation in recipients with SARS-cov-2 infection: a 282-case single-center experience in Japan.

BACKGROUND: The coronavirus disease 2019, caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), has become a global epidemic. There are concerns regarding the severity of SARS-CoV-2 infections in kidney transplant (KTx) recipients. However, there is limited data on how the epidemic has affected the treatment and prognosis of these patients. Therefore, we aimed to report the changes in the treatment and outcomes of KTx recipients infected with SARS-CoV-2 during each wave at our institution. METHODS: A total of 282 KTx recipients who were infected with SARS-CoV-2 during the study period were followed up at Tokyo Women's Medical University between March 2020 and August 2022. We investigated the outcomes and treatments of infected KTx recipients. RESULTS: Nineteen (6.7%) patients showed severe outcomes, including eight SARS-CoV-2 infection-related deaths. Risk factors associated with severe outcomes included underlying conditions, such as diabetes mellitus, heart disease, and liver disease (odds ratios, 2.09, 2.88, and 5.52, respectively). Treatment strategies changed throughout the epidemic in response to changes in the SARS-CoV-2 variants. Antiviral drugs were gradually administered as soon as they were approved for use. CONCLUSIONS: Treatment strategies for KTx recipients were gradually established over the course of the epidemic. Although the proportion of infected KTx recipients decreased compared to that of the general population throughout the epidemic, many patients still followed a severe course.

Unveiling Spatial Immune Cell Profile in Kidney Allograft Rejections Using 36-plex Immunofluorescence Imaging.

BACKGROUND: Kidney allograft rejections are orchestrated by a variety of immune cells. Because of the complex histopathologic features, accurate pathological diagnosis poses challenges even for expert pathologists. The objective of this study was to unveil novel spatial indices associated with transplant rejection by using a spatial bioinformatic approach using 36-plex immunofluorescence image data. METHODS: The image obtained from 11 T cell-mediated rejection (TCMR) and 12 antibody-mediated rejection (AMR) samples were segmented into 753 737 single cells using DeepCell's Mesmer algorithm. These cells were categorized into 13 distinct cell types through unsupervised clustering based on their biomarker expression profiles. Cell neighborhood analysis allowed us to stratify kidney tissue into 8 distinct neighborhood components consisting of unique cell type enrichment profiles. RESULTS: In contrast to TCMR samples, AMR samples exhibited a higher frequency of neighborhood components that were characterized by an enrichment of CD31+ endothelial cells. Although the overall frequency of CD68+ macrophages in AMR samples was not significantly high, CD68+ macrophages within endothelial cell-rich lesions exhibited a significantly higher frequency in AMR samples than TCMR samples. Furthermore, the frequency of interactions between CD31+ cells and CD68+ cells was significantly increased in AMR samples, implying the pivotal role of macrophages in AMR pathogenesis. Importantly, patients demonstrating a high frequency of CD31:CD68 interactions experienced significantly poorer outcomes in terms of chronic AMR progression. CONCLUSIONS: Collectively, these data indicate the potential of spatial bioinformatic as a valuable tool for aiding in pathological diagnosis and for uncovering new insights into the mechanisms underlying transplant rejection.

Renal outcome of living kidney donors aged more than 70 years.

BACKGROUND: The number of marginal living kidney donors has increased. Medically complex donors who have hypertension, older age, or low estimated glomerular filtration rate (eGFR) have been more likely to be used. METHODS: We conducted a retrospective cohort study of living kidney donors at a single center. We analyzed 309 living donors and divided them into three groups: group with older donors (aged ≥70 years) (n = 41), middle-aged (aged 46-69 years) (n = 239), and young donors (aged <46 years) (N = 29). Donor factors associated with chronic kidney disease (CKD) stage 3b or worse within 5 years post-donation were investigated. RESULTS: Of the 309 live donors, 86 (27.8%) developed CKD stage3b or worse within 5 years post-donation. The incidence of CKD stage3b or worse within 5 years post-donation was significantly higher in older donor (p < 0.01). Cox regression models revealed that older donor ages and lower eGFR were significantly related to the development of CKD stage3b or worse, independent of comorbidities such as obesity and hypertension [hazard ratio (95% CI); 4.59 (1.02-20.6), p = 047, 0.95 (0.94-0.96), p ≤ 0.01, respectively]. However, recovery of eGFR 4-5 years after donation was noted in the middle-aged and older donor groups, whereas the level of eGFR remained unchanged in the young group. CONCLUSIONS: Older donors tend to develop CKD stage3b within 5 years post-donation but with the potential of recovery. Healthy older people (aged ≥70 years) could be candidates for living donors under careful monitoring of kidney function after donation.

En bloc kidney transplantation from pediatric donors to teenage recipients: Two case reports.

Introduction: Since the implementation of the new selection criteria in 2018, kidney donations from pediatric patients have been prioritized for pediatric recipients and kidney donations from pediatric donors have increased in Japan. Herein, we present two cases of en bloc kidney transplantation. Case presentation: Case 1: A 19-year-old male patient who had been on hemodialysis for 5 years due to end-stage renal disease. After brain death, a graft from a 5-year-old boy was transplanted into the right iliac fossa. Case 2: A 19-year-old male patient, who had previously undergone a living kidney transplantation at the age of 3, received a secondary cadaveric kidney transplantation in the left iliac fossa. The graft was procured from a 17-month-old girl following cardiac death. Conclusion: This report will help surgeons perform en bloc kidney transplantation in the growing number of pediatric kidney donations, such as those in Japan.

Safety of Docetaxel in a Patient with Metastatic Castration-Resistant Prostate Cancer After Kidney Transplantation: A Case Report.

BACKGROUND: There are limitations in treating advanced prostate cancer (PC), especially castration-resistant (CR) cases, in renal transplant recipients (RTRs). We describe the case of RTR with metastatic CRPC (mCRPC) treated with docetaxel. CASE REPORT: A 60-year-old man with end-stage renal disease due to autosomal-dominant polycystic kidney disease (ADPKD) underwent living-related kidney transplantation. A year later, he was diagnosed with PC (prostate-specific antigen level: 998 ng/mL). Prostate biopsy revealed prostatic adenocarcinoma with a Gleason score of 4 + 4 = 8. Radiographic examination revealed seminal vesicle invasion and multiple bone and lymph node metastases. Combined androgen blockade therapy was initiated; however, the patient was diagnosed with CRPC 6 months later. Triweekly docetaxel therapy was administered 28 months after diagnosis. The patient successfully completed 7 cycles of this therapy without major adverse events. However, after the 7th cycle, he developed a high fever caused by an infection of ADPKD-associated renal cysts. Therefore, docetaxel was discontinued, and enzalutamide was started, followed by abiraterone, but without any effect. We then introduced cabazitaxel but discontinued it because of hepatic dysfunction. Hence, the patient underwent a docetaxel rechallenge. He was administered the PEGylated form of the recombinant human granulocyte colony-stimulating factor for neutropenia prophylaxis. After 6 cycles of rechallenge docetaxel therapy, the patient accidentally fell, resulting in a cervical spine fracture and subsequent death due to respiratory failure. CONCLUSIONS: Docetaxel can be safely delivered to patients with CRPC after renal transplantation who are taking oral immunosuppressants. It can be a good treatment option for them.

Higher Donor Age and Severe Microvascular Inflammation Are Risk Factors for Chronic Rejection After Treatment of Active Antibody-Mediated Rejection.

Recent developments in intensive desensitization protocols have enabled kidney transplantation in human leukocyte antigen (HLA)-sensitized recipients. However, cases of active antibody-mediated rejection (AABMR), when they occur, are difficult to manage, graft failure being the worst-case scenario. We aimed to assess the impact of our desensitization and AABMR treatment regimen and identify risk factors for disease progression. Among 849 patients who underwent living-donor kidney transplantation between 2014 and 2021 at our institution, 59 were diagnosed with AABMR within 1 year after transplantation. All patients received combination therapy consisting of steroid pulse therapy, intravenous immunoglobulin, rituximab, and plasmapheresis. Multivariable analysis revealed unrelated donors and preformed donor-specific antibodies as independent risk factors for AABMR. Five-year death-censored graft survival rate was not significantly different between patients with and without AABMR although 27 of 59 patients with AABMR developed chronic AABMR (CABMR) during the study period. Multivariate Cox proportional hazard regression analysis revealed that a donor age greater than 59 years and microvascular inflammation (MVI) score (g + ptc) ≥4 at AABMR diagnosis were independent risk factors for CABMR. Our combination therapy ameliorated AABMR; however, further treatment options should be considered to prevent CABMR, especially in patients with old donors and severe MVI.

The medical cost and outcome of desensitization protocol in kidney transplantation recipients with high immunological risks.

BACKGROUND: Kidney transplantation is a well-established alternative in renal replacement therapy. Compared with hemodialysis, low-immunological-risk kidney transplantation can reduce the medical treatment costs associated with end-stage renal disease. However, there are few reports on whether high-immunological-risk kidney transplantation reduces the financial burden on governments. We investigated the medical costs of high-immunological-risk kidney transplantation in comparison with the cost of hemodialysis in Japan. METHODS: We compared the medical costs of high-immunological-risk kidney transplantation with those of hemodialysis. 15 patients who underwent crossmatch-positive and/or donor-specific antibody-positive kidney transplantations between 2020 and 2021 were enrolled in this study. The patients received intravenous immunoglobulin, plasmapheresis, and rituximab as desensitizing therapy. RESULTS: Acute antibody-mediated rejection was detected in nine (60%) recipients, while there were no indications of graft function deterioration during the follow-up. For each patient, the transplant hospitalization cost was 38 428 ± 8789 USD. However, the cumulative costs were 59 758 ± 10 006 USD and 79 781 ± 16 366 USD, at 12 and 24 months, respectively. Compared with hemodialysis (34 286 USD per year), high-immunological-risk kidney transplantation tends to be expensive in the first year, but the cost is likely to be lower than that of hemodialysis after 3 years. CONCLUSIONS: Although kidney transplantation is initially expensive compared with hemodialysis, the medical cost becomes advantageous after 3 years even in kidney transplant recipients with high immunological risk.

Clinical Course of Candidate Renal Transplant Recipients Diagnosed With Prostate Cancer During Pre-transplant Screening Test.

BACKGROUND/AIM: Occasionally, candidate renal transplant recipients (RTRs) are incidentally diagnosed with prostate cancer (PCa) during pre-transplant screening examinations; however, their clinical course remains unclear. This study aimed to clarify the clinical course of RTR diagnosed with PCa during pre-transplant screening tests. PATIENTS AND METHODS: Between April 2008 and April 2022, 15 candidates for RTRs were newly diagnosed with PCa during the screening test. We analyzed the patients' treatment choices, initial treatment results, waiting duration for renal transplantation, and whether they finally underwent transplantation. RESULTS: The median patient age was 64 years (range=52-75 years). The median prostate-specific antigen level was 6.9 ng/ml (5.2-56.9 ng/ml). According to D'Amico risk stratification, one, 10, and four patients were at low, intermediate, and high risk, respectively. As for treatment choice, 13 patients chose surgery. Moreover, intensity-modulated radiotherapy and hormone therapy were chosen by one patient each. Of these, seven patients underwent transplantation, with a median waiting time from initial treatment to transplantation of 20.3 months (9.2-40.0 months). One patient discontinued transplantation owing to poor cancer control, four patients had donor issues (change in mind, aging, or disease), and one patient waited because pathological findings revealed locally invasive cancer. CONCLUSION: PCa diagnosis in candidate RTRs during the pre-transplant screening test impacts the candidate's clinical course.

Kidney Transplantation After Multiple Urinary Tract Conversion with an Ileal Conduit: A Case Report.

BACKGROUND: Kidney transplantation (KTx) after urinary tract conversion surgery is extremely difficult due to several complications. In our case, KTx was performed after multiple operative procedures, including diversion urethrostomy. CASE REPORT: The patient was a 46-year-old woman with a right atrophic kidney, an ectopic opening of the left ureter, and urethral dysplasia since birth. The patient underwent a right nephrectomy, left ureteral sigmoidostomy, Stamey surgery, augmentation ileocystoplasty, and left ureteroileostomy. Thereafter, she underwent nephrostomy, ileal conduit diversion, open sigmoid colectomy, and total cystectomy because of persistent urinary incontinence, sigmoid colon cancer, and recurrent cystitis. Her renal function gradually deteriorated, and hemodialysis was initiated. Before the KTx, she underwent laparoscopic left nephrectomy, an intraperitoneal adhesion debridement, and left ileal conduit resection. We dissected the left ileal conduit in the abdominal cavity and penetrated the anorectal side of the free ileal conduit into the wall of the right side of the abdomen. Thereafter, a kidney from a living donor was transplanted into the right iliac fossa through the existing right ileal conduit when the patient was 46 years old. The allograft function was stable without rejection for 2 years. CONCLUSIONS: We report the case of a patient who underwent multiple urethral modifications followed by ileal conduit transfer and living donor KTx, which progressed without major postoperative complications.

Pregnancy Complications and Impact on Kidney Allograft After Kidney Transplantation in IgA Nephropathy.

Pregnancy in kidney transplantation (KT) recipients has been challenging because of the high risk of maternal, fetal, and renal complications. Although patients with immunoglobulin A nephropathy (IgAN)-chronic kidney disease (CKD) are at a high risk for hypertension in pregnancy (HIP), the maternal risk in KT recipients with IgAN as the etiology remains unclear. We retrospectively reviewed the medical records of pregnant KT recipients who delivered at our hospital. The incidence of maternal and fetal complications and the impact on kidney allografts between the group with IgAN as the primary kidney disease and the group with other primary diseases were compared. The analysis included 73 pregnancies in 64 KT recipients. The IgAN group had a higher incidence of HIP than the non-IgAN group (69% vs. 40%, p = 0.02). IgAN as primary kidney disease and interval from transplantation to conception were associated with HIP (OR 3.33 [1.11-9.92], p = 0.03, OR 0.83 [0.72-0.96], p < 0.01, respectively). The 20-year graft survival or prevention of CKD stage 5 in group with IgAN was lower than that in the group with other primary disease (p < 0.01). KT recipients should be informed of the risk of HIP and possibility of long-term worsening of postpartum renal function.

Analysis of the T-cell repertoire and transcriptome identifies mechanisms of regulatory T-cell suppression of GVHD.

CD4+FOXP3+ regulatory T cells (Tregs) have demonstrated efficacy in the prevention and treatment of graft-versus-host disease (GVHD). Preclinical and clinical studies indicate that Tregs are able to protect from GVHD without interfering with the graft-versus-tumor (GVT) effect of hematopoietic cell transplantation (HCT), although the underlying molecular mechanisms are largely unknown. To elucidate Treg suppressive function during in vivo suppression of acute GVHD, we performed paired T-cell receptor (TCRα and ΤCRß genes) repertoire sequencing and RNA sequencing analysis on conventional T cells (Tcons) and Tregs before and after transplantation in a major histocompatibility complex -mismatched mouse model of HCT. We show that both Tregs and Tcons underwent clonal restriction, and Tregs did not interfere with the activation of alloreactive Tcon clones and the breadth of their TCR repertoire but markedly suppressed their expansion. Transcriptomic analysis revealed that Tregs predominantly affected the transcriptome of CD4 Tcons and, to a lesser extent, that of CD8 Tcons, thus modulating the transcription of genes encoding pro- and anti-inflammatory molecules as well as enzymes involved in metabolic processes, inducing a switch from glycolysis to oxidative phosphorylation. Finally, Tregs did not interfere with the induction of gene sets involved in the GVT effect. Our results shed light onto the mechanisms of acute GVHD suppression by Tregs and will support the clinical translation of this immunoregulatory approach.

Prevention of acute GVHD using an orthogonal IL-2/IL-2Rß system to selectively expand regulatory T cells in vivo.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative option for patients with hematological disorders and bone marrow (BM) failure syndromes. Graft-versus-host disease (GVHD) remains a leading cause of morbidity posttransplant. Regulatory T cell (Treg) therapies are efficacious in ameliorating GVHD but limited by variable suppressive capacities and the need for a high therapeutic dose. Here, we sought to expand Treg in vivo by expressing an orthogonal interleukin 2 receptor ß (oIL-2Rß) that would selectively interact with oIL-2 cytokine and not wild-type (WT) IL-2. To test whether the orthogonal system would preferentially drive donor Treg expansion, we used a murine major histocompatibility complex-disparate GVHD model of lethally irradiated BALB/c mice given T cell-depleted BM from C57BL/6 (B6) mice alone or together with B6Foxp3+GFP+ Treg or oIL-2Rß-transduced Treg at low cell numbers that typically do not control GVHD with WT Treg. On day 2, B6 activated T cells (Tcons) were injected to induce GVHD. Recipients were treated with phosphate-buffered saline (PBS) or oIL-2 daily for 14 days, then 3 times weekly for an additional 14 days. Mice treated with oIL-2Rß Treg and oIL-2 compared with those treated with PBS had enhanced GVHD survival, in vivo selective expansion of Tregs, and greater suppression of Tcon expansion in secondary lymphoid organs and intestines. Importantly, oIL-2Rß Treg maintained graft-versus-tumor (GVT) responses in 2 distinct tumor models (A20 and MLL-AF9). These data demonstrate a novel approach to enhance the efficacy of Treg therapy in allo-HSCT using an oIL-2/oIL-2Rß system that allows for selective in vivo expansion of Treg leading to GVHD protection and GVT maintenance.

IL-2 receptor engineering enhances regulatory T cell function suppressed by calcineurin inhibitor.

Clinical trials utilizing regulatory T cell (Treg) therapy in organ transplantation have shown promising results, however, the choice of a standard immunosuppressive regimen is still controversial. Calcineurin inhibitors (CNIs) are one of the most common immunosuppressants for organ transplantation, although they may negatively affect Tregs by inhibiting IL-2 production by conventional T cells. As a strategy to replace IL-2 signaling selectively in Tregs, we have introduced an engineered orthogonal IL-2 (ortho IL-2) cytokine/cytokine receptor (R) pair that specifically binds with each other but does not bind with their wild-type counterparts. Murine Tregs were isolated from recipients and retrovirally transduced with ortho IL-2Rß during ex vivo expansion. Transduced Tregs (ortho Tregs) were transferred into recipient mice in a mixed hematopoietic chimerism model with tacrolimus administration. Ortho IL-2 treatment significantly increased the ortho IL-2Rß(+) Treg population in the presence of tacrolimus without stimulating other T cell subsets. All the mice treated with tacrolimus plus ortho IL-2 achieved heart allograft tolerance, even after tacrolimus cessation, whereas those receiving tacrolimus treatment alone did not. These data demonstrate that Treg therapy can be adopted into a CNI-based regimen by utilizing cytokine receptor engineering.

Role of Fractalkine-CX3CR1 Axis in Acute Rejection of Mouse Heart Allografts Subjected to Ischemia Reperfusion Injury.

Transplantation outcomes are affected by the increase in rejection associated with ischemia reperfusion injury (IRI). Fractalkine (FKN), a chemokine for recruitment of CX3CR1+ leukocytes, contributes to the pathogenesis of various inflammatory diseases. Herein, we evaluated the importance of the FKN-CX3CR1 axis during IRI-related rejections using a mouse heterotopic heart transplantation model. FKN expression and graft survival was compared between wild-type C57BL/6 recipients transplanted with BALB/c hearts preserved for 8 (WT-IRI) and 0.5 h (WT-control) at 4°C. Graft survival of WT-IRI was shorter than that of WT-control. FKN was expressed on the vascular endothelium in WT-IRI allografts, but minimally in WT-control. The role of the FKN-CX3CR1 axis in IRI-related rejection was directly investigated using the transplant model with CX3CR1-deficient recipients (CX3CR1 KO-IRI) or treatment with anti-mouse FKN monoclonal antibodies. Graft survival of CX3CR1 KO-IRI was longer than that of WT-IRI; antibody treatment prolonged graft survival. The contribution of CX3CR1+ monocytes to IRI-related rejection was evaluated by adoptive transfer to CX3CR1 KO-IRI. Adoptive transfer of CX3CR1+ monocytes attenuated the effect of prolonged graft survival in CX3CR1 KO-IRI. Overall, the FKN-CX3CR1 axis plays a major role during IRI-related rejection; its blockade has the potential to improve the outcomes of deceased donor transplantation.

Allogeneic CAR Invariant Natural Killer T Cells Exert Potent Antitumor Effects through Host CD8 T-Cell Cross-Priming.

PURPOSE: The development of allogeneic chimeric antigen receptor (CAR) T-cell therapies for off-the-shelf use is a major goal that faces two main immunologic challenges, namely the risk of graft-versus-host disease (GvHD) induction by the transferred cells and the rejection by the host immune system limiting their persistence. In this work we assessed the direct and indirect antitumor effect of allogeneic CAR-engineered invariant natural killer T (iNKT) cells, a cell population without GvHD-induction potential that displays immunomodulatory properties. EXPERIMENTAL DESIGN: After assessing murine CAR iNKT cells direct antitumor effects in vitro and in vivo, we employed an immunocompetent mouse model of B-cell lymphoma to assess the interaction between allogeneic CAR iNKT cells and endogenous immune cells. RESULTS: We demonstrate that allogeneic CAR iNKT cells exerted potent direct and indirect antitumor activity when administered across major MHC barriers by inducing tumor-specific antitumor immunity through host CD8 T-cell cross-priming. CONCLUSIONS: In addition to their known direct cytotoxic effect, allogeneic CAR iNKT cells induce host CD8 T-cell antitumor responses, resulting in a potent antitumor effect lasting longer than the physical persistence of the allogeneic cells. The utilization of off-the-shelf allogeneic CAR iNKT cells could meet significant unmet needs in the clinic.

Imaging alloreactive T cells provides early warning of organ transplant rejection.

Diagnosis of organ transplant rejection relies upon biopsy approaches to confirm alloreactive T cell infiltration in the graft. Immune molecular monitoring is under investigation to screen for rejection, though these techniques have suffered from low specificity and lack of spatial information. ImmunoPET utilizing antibodies conjugated to radioisotopes has the potential to improve early and accurate detection of graft rejection. ImmunoPET is capable of noninvasively visualizing the dynamic distribution of cells expressing specific immune markers in the entire body over time. In this work, we identify and characterize OX40 as a surrogate biomarker for alloreactive T cells in organ transplant rejection and monitor its expression by utilizing immunoPET. In a dual murine heart transplant model that has both syngeneic and allogeneic hearts engrafted in bilateral ear pinna on the recipients, OX40 immunoPET clearly depicted alloreactive T cells in the allograft and draining lymph node that were not observed in their respective isograft counterparts. OX40 immunoPET signals also reflected the subject's immunosuppression level with tacrolimus in this study. OX40 immunoPET is a promising approach that may bridge molecular monitoring and morphological assessment for improved transplant rejection diagnosis.

Activation of natural killer T cells enhances the function of regulatory T-cell therapy in suppressing murine GVHD.

Cellular therapy with regulatory T cells (Tregs) has shown promising results for suppressing graft-versus-host disease (GVHD) while preserving graft vs tumor effects in animal models and phase 1/2 clinical trials. However, a paucity of Tregs in the peripheral blood makes it difficult to acquire sufficient numbers of cells and hampers further clinical application. Invariant natural killer T (iNKT) cells constitute another compartment of regulatory cells that ameliorate GVHD through activation of Tregs after their own activation with α-galactosylceramide (α-GalCer) or adoptive transfer. We demonstrate here that a single administration of α-GalCer liposome (α-GalCer-lipo) enhanced the in vivo expansion of Tregs after adoptive transfer in a murine GVHD model and improved therapeutic efficacy of Treg therapy even after injection of otherwise suboptimal cell numbers. Host iNKT cells rather than donor iNKT cells were required for GVHD suppression because the survival benefit of α-GalCer-lipo administration was not shown in the transplantation of cells from wild-type (WT) C57BL/6 mice into Jα18-/- iNKT cell-deficient BALB/c mice, whereas it was observed from Jα18-/- C57BL/6 donor mice into WT BALB/c recipient mice. The combination of iNKT cell activation and Treg adoptive therapy may make Treg therapy more feasible and safer by enhancing the efficacy and reducing the number of Tregs required.

Invariant natural killer T-cell subsets have diverse graft-versus-host-disease-preventing and antitumor effects.

Invariant natural killer T (iNKT) cells are a T-cell subset with potent immunomodulatory properties. Experimental evidence in mice and observational studies in humans indicate that iNKT cells have antitumor potential as well as the ability to suppress acute and chronic graft-versus-host-disease (GVHD). Murine iNKT cells differentiate during thymic development into iNKT1, iNKT2, and iNKT17 sublineages, which differ transcriptomically and epigenomically and have subset-specific developmental requirements. Whether distinct iNKT sublineages also differ in their antitumor effect and their ability to suppress GVHD is currently unknown. In this work, we generated highly purified murine iNKT sublineages, characterized their transcriptomic and epigenomic landscape, and assessed specific functions. We show that iNKT2 and iNKT17, but not iNKT1, cells efficiently suppress T-cell activation in vitro and mitigate murine acute GVHD in vivo. Conversely, we show that iNKT1 cells display the highest antitumor activity against murine B-cell lymphoma cells both in vitro and in vivo. Thus, we report for the first time that iNKT sublineages have distinct and different functions, with iNKT1 cells having the highest antitumor activity and iNKT2 and iNKT17 cells having immune-regulatory properties. These results have important implications for the translation of iNKT cell therapies to the clinic for cancer immunotherapy as well as for the prevention and treatment of GVHD.

Selective expansion of regulatory T cells using an orthogonal IL-2/IL-2 receptor system facilitates transplantation tolerance.

Adoptive transfer of Tregs has been shown to improve alloengraftment in animal models. However, it is technically challenging to expand Tregs ex vivo for the purpose of infusing large numbers of cells in the clinic. We demonstrate an innovative approach to engineering an orthogonal IL-2/IL-2 receptor (IL-2R) pair, the parts of which selectively interact with each other, transmitting native IL-2 signals, but do not interact with the natural IL-2 or IL-2R counterparts, thereby enabling selective stimulation of target cells in vivo. Here, we introduced this orthogonal IL-2R into Tregs. Upon adoptive transfer in a murine mixed hematopoietic chimerism model, orthogonal IL-2 injection significantly promoted orthogonal IL-2R+Foxp3GFP+CD4+ cell proliferation without increasing other T cell subsets and facilitated donor hematopoietic cell engraftment followed by acceptance of heart allografts. Our data indicate that selective target cell stimulation enabled by the engineered orthogonal cytokine receptor improves Treg potential for the induction of organ transplantation tolerance.

Living-Donor Kidney Transplantation Performed in a Low-Volume Center by Visiting Surgeons From a High-Volume Center and Managed Clinically Solely by Nephrologists: 1-Year Outcomes.

BACKGROUND: Little is known about the outcome of living-donor kidney transplantation (LDKT) performed in low-volume centers lacking the services of full-time transplant surgeons. This retrospective cohort study assessed the outcome of LDKT performed in a low-volume center by visiting transplant surgeons from a high-volume center and managed perioperatively by transplant nephrologists. METHODS: We compared Japanese adult patients who had no donor-specific antibodies and underwent LDKT between 2006 and 2015 either in a low-volume (n = 31) or high-volume (n = 481) center. In the low-volume center, visiting transplant surgeons from the high-volume center conducted LDKT and transplant nephrologists managed the recipients peri- and postoperatively. The primary outcome was the composite of infection, cardiovascular disease, or cancer during 1-year follow-up. The outcomes of the low- and high-volume centers were compared using 1:2 propensity score matching. RESULTS: After matching, 9 of 29 patients in the low-volume center (31.0%) and 16 of 58 patients in the high-volume center (27.6%) experienced the primary composite outcome (risk ratio = 1.13; 95% confidence interval, 0.57-2.23). There were no significant differences between the 2 groups in graft function at 1 year, all-cause graft loss, biopsy-proven rejection, and urological complications. However, the median duration of post-LDKT hospitalization was significantly longer in the low-volume center than in the high-volume center (23 and 16 days, respectively). CONCLUSIONS: Among Japanese patients without preformed donor-specific antibodies, LDKT conducted at a low-volume center by visiting transplant surgeons from a high-volume center and managed clinically by transplant nephrologists was not associated with significantly higher risk of postoperative complications.