岩見 大基

BACKGROUND: Thrombotic microangiopathy (TMA) after kidney transplantation (KTx), particularly early onset de novo (dn) TMA, requires immediate interventions to prevent irreversible organ damage. This multicenter study was performed to investigate the allogeneic clinical factors and complement genetic background of dnTMA after KTx. METHODS: Perioperative dnTMA after KTx within 1 week after KTx were diagnosed based on pathological or/and hematological criteria at each center, and their immunological backgrounds were researched. Twelve aHUS-related gene variants were examined in dnTMA cases. RESULTS: Seventeen recipients (15 donors) were enrolled, and all dnTMA cases were onset within 72-h of KTx, and 16 of 17 cases were ABO incompatible. The implementation rate of pre-transplant plasmaphereses therapies were low, including cases with high titers of anti-A/anti-B antibodies. Examination of aHUS-related gene variants revealed some deletions and variants with minor allele frequency (MAF) in Japan or East Asian genome databases in genes encoding alternative pathways and complement regulatory factors. These variants was positive in 8 cases, 6 of which were positive in both recipient and donor, but only in one graft loss case. CONCLUSIONS: Although some immunological risks were found for dnTMA after KTx, only a few cases developed into TMA. The characteristic variations revealed in the present study may be novel candidates related to dnTMA in Japanese or Asian patients, but not pathogenic variants of aHUS. Future studies on genetic and antigenic factors are needed to identify factors contributing to dnTMA after KTx.

BACKGROUND: Non-invasive, prompt, and proper detection tools for kidney graft injuries (KGIs) are awaited to ensure graft longevity. We screened diagnostic biomarkers for KGIs following kidney transplantation using extracellular vesicles (EVs; exosomes and microvesicles) from the urine samples of patients. METHODS: One hundred and twenty-seven kidney recipients at 11 Japanese institutions were enrolled in this study; urine samples were obtained prior to protocol/episode biopsies. EVs were isolated from urine samples, and EV RNA markers were assayed using quantitative reverse transcription polymerase chain reaction. Diagnostic performance of EV RNA markers and diagnostic formulas comprising these markers were evaluated by comparison with the corresponding pathological diagnoses. RESULTS: EV CXCL9, CXCL10, and UMOD were elevated in T-cell-mediated rejection samples compared with other KGI samples, while SPNS2 was elevated in chronic antibody-mediated rejection (cABMR) samples. A diagnostic formula developed through Sparse Logistic Regression analysis using EV RNA markers allowed us to accurately (with an area under the receiver operator characteristic curve [AUC] of 0.875) distinguish cABMR from other KGI samples. EV B4GALT1 and SPNS2 were also elevated in cABMR, and a diagnostic formula using these markers was able to distinguish between cABMR and chronic calcineurin toxicity accurately (AUC 0.886). In interstitial fibrosis and tubular atrophy (IFTA) urine samples and those with high Banff chronicity score sums (BChS), POTEM levels may reflect disease severity, and diagnostic formulas using POTEM detected IFTA (AUC 0.830) and high BChS (AUC 0.850). CONCLUSIONS: KGIs could be diagnosed with urinary EV mRNA analysis with relatively high accuracy.

Donor-specific antibodies (DSAs) are the main cause of graft loss over time. The direct pathway of alloantigen recognition is important in the pathogenesis of acute rejection. Recent studies have suggested that the direct pathway also contributes to the pathogenesis of chronic injury. Nevertheless, there are no reports on T-cell alloantigen response via the direct pathway in kidney recipients with DSAs. We analyzed the T-cell alloantigen response via the direct pathway in kidney recipients with DSAs (DSA+) or without DSAs (DSA-). A mixed lymphocyte reaction assay was implemented to assess the direct pathway response. DSA+ patients showed significantly higher CD8+ and CD4+ T cell responses to donor cells than DSA- patients. Furthermore, proliferating CD4+ T cells showed a marked increase in Th1 and Th17 responses in DSA+ patients than in DSA- patients. In a comparison between anti-donor and third-party responses, the anti-donor CD8+ and CD4+ T cell response was significantly lower than the anti-third-party response. In contrast, the donor-specific hyporesponsiveness was absent in DSA+ patients. Our study demonstrated that DSA+ recipients have a greater potential for developing immune responses against the donor tissues via the direct alloantigen recognition pathway. These data contribute to an understanding of DSAs pathogenicity during kidney transplantation.

Donors with resolved hepatitis B virus (HBV) infection may be a solution for the organ shortage for kidney transplantation (KT). The purpose of this study was to clarify the current state of HBV markers after KT from donors with resolved HBV infection to HBV naïve recipients and the rate of HBV reactivation in recipients with resolved HBV infection. Furthermore, we investigated HBV covalently closed circular DNA (cccDNA) in transplanted organs from donors with resolved HBV infection and the capability of HBV replication in kidney cell lines. We retrospectively analysed the HBV status of 340 consecutive donors and recipients who underwent KT in a single centre. We prospectively measured cccDNA by real-time polymerase chain reaction in kidney biopsy specimens of 32 donors with resolved HBV infection. HBV reactivation was found in three recipients with resolved HBV infection (4.8%, 3/63) after KT. We analysed 45 cases of transplantation from donors with resolved HBV infection to HBV-naive recipients. One case (2.2%, 1/45) became seropositive for hepatitis B core antibody (anti-HBc) and in another case (2.2%, 1/45), HBV-DNA was detected qualitatively in an HBV naive recipient with a donor with resolved HBV infection. In the latter case, cccDNA was measured in the donor kidney during KT. HBV replication was observed in kidney cell lines with HBV plasmid transfection. In conclusion, the risk of reactivation in anti-HBc-positive donors is relatively low. However, post-transplant HBV monitoring should be conducted in all at-risk cases.

Introduction: We present a case of urothelial carcinoma in a renal allograft successfully treated with pembrolizumab. Case presentation: A 39-year-old woman presented with nausea and anorexia 9 years after a renal transplantation. Positron emission tomography revealed a neoplasm of the renal pelvis of the allograft and multiple lymph nodes with peritoneal metastasis. A diagnosis of a non-muscle-invasive bladder tumor with peritoneal dissemination and jejunal metastasis of urothelial carcinoma was made. After five cycles of gemcitabine and carboplatin, the tumor progressed and pembrolizumab was administered. One week after the first dose, the allograft was rejected, necessitating arterial embolization. After the second cycle, the patient developed Stevens-Johnson syndrome. After discontinuing pembrolizumab, positron emission tomography revealed no increased tumor activity. A complete response was achieved for 21 months without additional treatment. Conclusion: Pembrolizumab was effective in treating urothelial carcinoma of the renal allograft; however, allograft rejection and loss should be considered.

We report a case of bladder cancer in a 54-year-old woman who underwent renal transplantation for chronic renal failure. Six years after the transplantation, she was diagnosed with muscle-invasive bladder cancer with multiple lung metastases. She received gemcitabine/cisplatin therapy for Stage IV bladder cancer, and the dose of the immunosuppressants was reduced to prevent adverse effects. Since lung metastatic lesions disappeared after four courses of chemotherapy and no new lesions were found, we performed radical cystectomy and right nephroureterectomy with ileal conduit construction. Although she was followed closely without therapy, multiple lung metastases appeared 6 months after the radical cystectomy. Gemcitabine/carboplatin therapy was administered, and the lung metastasis improved slightly until the end of the 4th course, but aggressive growth was observed after the 5th course. She switched to palliative treatment without requesting additional treatment and died of cancer 1 year and 9 months after total cystectomy.There is no evidence-based treatment strategy for advanced bladder cancer after kidney transplantation. It is necessary to recognize that the patient had renal dysfunction and was in an immunosuppressed state. Thus, it is crucial to select appropriate drug and surgical treatments for each patient.

Background: A positive flow-cytometry T cell crossmatch (FTXM) has important prognostic implications, even when the complement-dependent cytotoxicity crossmatch is negative. Recent studies have shown that ABO incompatibility is associated with positive FTXM, but the underlying mechanism remains poorly understood. Cases: In five ABO blood type O recipients of kidneys from wives with type B, FTXM was positive but complement-dependent cytotoxicity crossmatch was negative. Application of a solid-phase technique (LABScreen) revealed no case with antibodies to donor-specific human leukocyte antigen. After removal of type B antibodies from patient sera, FTXM was negative for all five patients. In one tested case, the eluate prepared from the donor's T lymphocyte agglutinated only type B red blood cells, implying the existence of blood type B substances on donor T lymphocytes. Discussion: False-positive FTXM reflects blood type B substrates bound to T lymphocytes. Repeat FTXM after incubation with donor-type red blood cells (to adsorb anti-ABO antibodies) was negative. This phenomenon explains the discrepancy between FTXM and solid-phase bead assays. Demonstration of type B substances on donor T lymphocytes is necessary before absolute test validity is confirmed. Conclusion: False-positive FTXM may be associated with type B antibodies bound to T lymphocytes when a blood type O recipient receives tissue from a type B donor. This phenomenon explains the false-positive FTXM observed in the setting of ABO-incompatible kidney transplantation.

Surgical training using live animals such as pigs is one of the best ways of achieving skilled techniques and fostering confidence in preclinical medical students and surgeon trainees. However, due to animal welfare ethics, laboratory animals' usage for training should be kept to a minimum. We have developed a novel kidney organ model utilizing a simple procedure in which the kidney is first refluxed with N-vinyl-2-pyrrolidone (NVP) solution for 1 hour in its bath, followed by permeation for 23 hours, with a subsequent freshwater refluxed for 48 hours in the washing step. Surgical simulation of the prepared kidney model (NVP-fixed kidney) was compared with three types of other basic known simulation models (fresh kidney, freeze-thaw kidney, and FA-fixed kidney) by various evaluations. We found the NVP-fixed kidney to mimicked fresh kidney function the most, pertaining to the hardness, and strength of the renal parenchyma. Moreover, the NVP-fixed kidney demonstrated successful blood-like fluids perfusion and electrocautery. Further, we confirmed that surgical training could be performed under conditions closer to actual clinical practice. Our findings suggest that our model does not only contribute to improving surgical skills but also inspires the utilization of otherwise, discarded inedible livestock organs as models for surgical training.

<title>Abstract</title><sec> <title>Background</title> Simultaneous pancreas and kidney transplantation (SPK) is a treatment option for patients with end-stage renal disease due to type 1 diabetes mellitus. We report a patient with a refractory fistula due to leakage from the duodenal stump of the pancreas graft after an SPK with bladder drainage who was successfully treated with a percutaneous direct injection of <italic>N</italic>-butyl-2-cyanoacrylate (NBCA). </sec><sec> <title>Case presentation</title> A 60-year-old female with a 33-year history of type 1 diabetes mellitus and a 10-year history of renal replacement therapy underwent an SPK in 2015. At the time of transplantation, an abdominal aortic aneurysm with a high risk of rupture was treated by a Y-graft replacement prior to the SPK. Bladder drainage of the pancreas graft was chosen to avoid a vessel graft infection. The patient’s postoperative course was uneventful. The patient was discharged on postoperative day 93 with good-functioning pancreas and kidney grafts. One and a half years after the operation, the patient was found to have acute graft pancreatitis and a leak from the duodenal stump of the pancreas graft due to a paralytic neurogenic bladder. The insertion of an indwelling catheter into the bladder and the endoscopic-guided insertion of a catheter into the graft pancreatic duct through the duodenum/bladder anastomosis did not result in the closure of the fistula. Therefore, NBCA was injected at the site of the leak point using CT-guided technique. The fistula was completely closed immediately after the injection, with no recurrences of leaks. </sec><sec> <title>Conclusions</title> A percutaneous direct injection of NBCA is one of the treatment options to treat intractable fistulas. </sec>

Herein we report the case of a 37-year-old woman with recurrence of lupus nephritis (LN) in a renal allograft during pregnancy. She had developed end-stage renal disease due to LN and was put on hemodialysis at the age of 26 years. She underwent kidney transplantation at the age 28 years. Maintenance immunosuppressants included methylprednisolone, tacrolimus, and mycophenolate mofetil, which were changed to azathioprine when she desired pregnancy. The renal allograft function remained stable and seemingly disease-free until proteinuria and functional decline occurred during the pregnancy (age: 34 years). The baby was delivered by performing a cesarean section at 33 weeks of gestation. Renal allograft biopsy revealed crescent formation. Light microscopy revealed tuft necrosis and endocapillary proliferation. Immunofluorescence microscopy revealed the deposition of immunoglobulin G and C1q. A recurrence of LN (ISN/RPS class IV-G [A/C]) was diagnosed, and the patient was treated with pulse steroid therapy and azathioprine was replaced with mycophenolate mofetil. This treatment improved acute or active lesions of LN and temporarily benefited the renal allograft function. Unfortunately, there were irreversible chronic changes and a gradual decline in the renal allograft function.

OBJECTIVES: To evaluate the relationship between the creatinine reduction ratio between postoperative days 1 and 2 and post-transplantation clinical outcomes after living donor kidney transplantation. METHODS: Clinical data of patients who underwent living donor kidney transplantation at Jichi Medical University Hospital, Tochigi, Japan, between 2006 and 2019 were retrieved. The creatinine reduction ratio between postoperative days 1 and 2 was calculated based on the formula: (Cre1 - Cre2) × 100/Cre1; patients were then classified into either the slow graft function (creatinine reduction ratio between postoperative days 1 and 2 ≤30%) or immediate graft function (creatinine reduction ratio between postoperative days 1 and 2 >30%) group. We carried out the log-rank test and multivariate Cox proportional hazards regression analyses to assess graft survival and rejection-free survival, and the unpaired t-test and multivariate linear regression to assess post-transplantation estimated glomerular filtration rates. Multivariate analyses used age, sex, dialysis duration, ABO compatibility, donor-specific antibody positivity and medically complex living donors as explanatory variables. RESULTS: Of the 272 patients, 30 and 242 were in the slow graft function and immediate graft function groups, respectively. Multivariate Cox proportional hazards regression analyses showed a significantly higher incidence of overall and death-censored graft loss in the slow graft function group than the immediate graft function group. The frequency of rejection after 1 week post-transplantation did not differ within the groups. Post-transplantation estimated glomerular filtration rates tended to decline earlier in the slow graft function group than in the immediate graft function group; however, the difference was not statistically significant. CONCLUSIONS: The creatinine reduction ratio between postoperative days 1 and 2 could potentially predict long-term outcomes after living donor kidney transplantation. Using the creatinine reduction ratio between postoperative days 1 and 2 and other conventional indicators might allow accurate risk classification and appropriate therapeutic interventions.

Introduction: After kidney transplantation, patients should be treated with caution and monitored for surgical complications. Among the possible surgical complications, strangulation ileus after kidney transplantation is rare. Case presentation: A 59-year-old woman who had undergone kidney transplantation at 41 years of age presented to our hospital with lower abdominal pain. She was diagnosed with strangulation ileus and underwent emergency surgery. In the lower right abdomen, the small intestine was compressed by cord-like tissue running from the intraperitoneal space to the retroperitoneal space. We confirmed that the cord-like tissue was the ureter of the transplanted kidney. The necrotic small intestine was resected, and ureter-ureteral anastomosis of the ureter of the transplanted kidney was performed. Conclusion: All surgical procedures, including ureteroneocystostomy, require careful attention. The occurrence of some postoperative surgical complications can be prevented by carefully performing the kidney transplantation procedure.

Anemia and vitamin D deficiency are associated with allograft failure, and hence, are potential therapeutic targets among kidney transplant recipients (KTRs). We conducted a multicenter, two-by-two factorial, open-label, randomized clinical trial to examine the effects of anemia correction and vitamin D supplementation on 2-year change in eGFR among KTRs (CANDLE-KIT). We enrolled 153 patients with anemia and >1-year history of transplantation across 23 facilities in Japan, and randomly assigned them to either a high or low hemoglobin target (>12.5 vs. <10.5 g/dl) and to either cholecalciferol 1000 IU/day or control. This trial was terminated early based on the planned interim intention-to-treat analyses (α = 0.034). Among 125 patients who completed the study, 2-year decline in eGFR was smaller in the high vs. low hemoglobin group (i.e., -1.6 ± 4.5 vs. -4.0 ± 6.9 ml/min/1.73 m2 ; P = 0.021), but did not differ between the cholecalciferol and control groups. These findings were supported by the fully adjusted mixed effects model evaluating the rate of eGFR decline among all 153 participants. There were no significant between-group differences in all-cause death or the renal composite outcome in either arm. In conclusion, aggressive anemia correction showed a potential to preserve allograft kidney function.

PURPOSE: Although transplanting two kidneys from a single donor to two recipients has some advantages, the right and left kidneys are not anatomically identical; thus, a surgical procedure considering the anatomical features of the donor kidneys is needed when transplanting them into the opposite renal fossae. Based on vast experience, the surgical details of pig orthotopic kidney transplantation from one donor to two recipients was reported. METHODS: When the right kidney was transplanted to the left renal fossa, the graft was inverted upside down, not backwards, thus ensuring that the anteroposterior relationship of the renal vessels was maintained and anatomically natural vascular anastomosis could be performed. RESULTS: Using this technique, we could have developed a pig experimental model that is safe and has a high success rate, even for researchers in the middle of their training. This technique of inverting the graft upside down was reported in human kidney transplantation to make vascular anastomosis easier. CONCLUSIONS: In pig orthotopic kidney transplantation from one donor to two recipients, an anatomically natural vascular anastomosis could be performed via inverted grafting when the right kidney was transplanted into the left renal fossa.

Introduction: Femoral nerve palsy is a rare but serious complication of kidney transplantation. We report a case of femoral nerve palsy following kidney transplantation and conduct a review of the literature on this complication. Case presentation: A 35-year-old woman with end-stage kidney disease, underwent kidney transplantation in the right iliac fossa. The day after the transplantation, she could not straighten her right leg. Physical examination revealed a paresis of her right quadriceps muscle. The patient's sensation of her right thigh was also impaired. We diagnosed her with femoral nerve palsy caused by inappropriate compression from a self-retaining retractor. Rehabilitation was started immediately. The patient's motor weakness gradually improved, and the patient became able to walk independently 4 weeks later. However, the patient's neuropathic pain sustained 6 months after her kidney transplantation. Conclusion: The improper use of self-retaining retractors can lead to femoral nerve palsy in patients undergoing kidney transplantation.

Chronic active antibody-mediated rejection (CAAMR) is a particular problem in kidney transplantation (KTx), and ~25% of grafts are lost by CAAMR. Further, the pathogenesis remains unclear, and there is no effective cure or marker. We previously found that a hyper NFκB-activating mechanism in non-immune cells, called the IL-6 amplifier, is induced by the co-activation of NFκB and STAT3, and that this activation can develop various chronic inflammatory diseases. Here, we show that synaptotagmin-17 (SYT17) is increased in an exosomal fraction of the urine from CAAMR patients, and that this increase is associated with activation of the IL-6 amplifier. Immunohistochemistry showed that SYT17 protein expression was increased in renal tubule cells of the CAAMR group. While SYT17 protein was not detectable in whole-urine samples by western blotting, urinary exosomal SYT17 levels were significantly elevated in the CAAMR group compared to three other histology groups (normal, interstitial fibrosis and tubular atrophy, and calcineurin inhibitors toxicity) after KTx. On the other hand, current clinical laboratory data could not differentiate the CAAMR group from these groups. These data suggest that urinary exosomal SYT17 is a potential diagnostic marker for CAAMR.