Analysis of T-cell alloantigen response via a direct pathway in kidney transplant recipients with donor-specific antibodies.

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.

A Case of Kidney Transplantation from a Deceased Donor with Acute Kidney Injury due to Rhabdomyolysis.

Acute kidney injury (AKI) due to rhabdomyolysis occurs because of renal ischemia or acute tubular necrosis due to the deposition of myoglobin casts in the renal tubules. Donors with AKI due to rhabdomyolysis are not contraindication for transplantation. However, the dark red kidney raises concerns about renal hypofunction or primary nonfunction after transplantation. We report the case of a 34-year-old man with a 15-year history of hemodialysis for chronic renal failure due to congenital anomalies of the kidney and urinary tract. The patient received a renal allograft from a young woman who suffered cardiac death. The serum creatinine (sCre) level of the donor at the time of transport was 0.6 mg/dL, and renal ultrasonography revealed no abnormalities in renal morphology or blood flow. Her serum creatinine kinase level increased to 57,000 IU/L 58 h after femoral artery cannulation and sCre level worsened to 1.4 mg/dL, suggesting AKI due to rhabdomyolysis. However, since the urine output of the donor was maintained, the sCre elevation was thought to be nonproblematic. The allograft had a dark red appearance at the time of procurement. The perfusion of the isolated kidney was good, but the dark red color did not improve. A 0-h biopsy showed flattening of the renal tubular epithelium and absence of the brush border and myoglobin casts in 30% of the renal tubules. Rhabdomyolysis-related tubular damage was diagnosed. Hemodialysis was discontinued on postoperative day 14. Twenty-four days after the operation, the transplanted kidney function progressed favorably (sCre 1.18 mg/dL), and the patient was discharged. Protocol biopsy 1 month after transplantation showed disappearance of myoglobin casts and improvement in renal tubular epithelial damage. The patient's sCre level was approximately 1.0 mg/dL 24 months after transplantation, and he is doing well without complications.

Successful immunomodulation in kidney transplant recipients with cytokine release syndrome after coronavirus disease.

Introduction: Patients with coronavirus disease, especially solid organ transplant recipients, are more susceptible to developing cytokine release syndrome than those with other viral infections. However, currently, treatment methods for such patients have not been established. Here, we describe two cases of successful immunomodulation in Japanese kidney transplant recipients with cytokine release syndrome following coronavirus disease. Case presentation: Two patients who had been receiving long-term immunosuppressant therapy developed coronavirus disease-associated pneumonia caused by cytokine release syndrome, following immunosuppressant dosage reduction. However, they recovered immediately after administration of tocilizumab with or without dexamethasone. Conclusion: The immunosuppressant dosage should be reduced to restore host immunity; however, immunomodulation should be considered in cases of suspected cytokine release syndrome.

Long-Term Outcome of ABO-Incompatible Kidney Transplantation in Patients Treated With Low-Dose Rituximab Regimen.

BACKGROUND: Introduction of rituximab in the desensitization protocols for ABO-incompatible (ABOI) kidney transplantation (KTX) has afforded excellent results. However, the acceptability of minimal dosage of rituximab in these protocols remains to be defined. METHODS: Sixty-three patients who underwent ABOI KTX were included in this study. The desensitization protocol consisted of plasmapheresis, tacrolimus, mycophenolate mofetil, methylprednisolone, intravenous immunoglobulin, basiliximab, and low-dose rituximab (100 mg/body). We evaluated the efficacy, safety, and long-term outcome of this protocol (group R, n = 39) and compared them with those of patients who underwent splenectomy (group S, n = 24). RESULTS: Graft and patient survival at 10 years after KTX were comparable between the groups (94.4% [group R] vs 95.4% [group S] and 94.6% [group R] vs 95.8% [group S], respectively). The incidence of acute antibody-mediated rejection (AAMR) was similar in the 2 groups (10.2% vs 12.5%). There were no significant differences in the incidence of chronic active antibody-mediated rejection. Of the patients, 7 developed AAMR and 3 of these patients (1 in group R and 2 in group S) lost their grafts. There were no significant differences in the incidence of chronic active antibody-mediated rejection. The incidence of postoperative cytomegalovirus infection in group R was significantly lower than that in group S. Furthermore, the incidence of postoperative late-onset neutropenia was low in group R. CONCLUSIONS: A low-dose rituximab regimen for ABOI KTX is acceptable for preventing AAMR with a low incidence of delayed adverse events.

Increased urinary exosomal SYT17 levels in chronic active antibody-mediated rejection after kidney transplantation via the IL-6 amplifier.

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.

Orosomucoid 1 is involved in the development of chronic allograft rejection after kidney transplantation.

Chronic allograft rejection is the most common cause of long-term allograft failure. One reason is that current diagnostics and therapeutics for chronic allograft rejection are very limited. We here show that enhanced NFκB signaling in kidney grafts contributes to chronic active antibody-mediated rejection (CAAMR), which is a major pathology of chronic kidney allograft rejections. Moreover, we found that urinary orosomucoid 1 (ORM1) is a candidate marker molecule and therapeutic target for CAAMR. Indeed, urinary ORM1 concentration was significantly higher in kidney transplant recipients pathologically diagnosed with CAAMR than in kidney transplant recipients with normal histology, calcineurin inhibitor toxicity, or interstitial fibrosis and tubular atrophy. Additionally, we found that kidney biopsy samples with CAAMR expressed more ORM1 and had higher NFκB and STAT3 activation in tubular cells than samples from non-CAAMR samples. Consistently, ORM1 production was induced after cytokine-mediated NFκB and STAT3 activation in primary kidney tubular cells. The loss- and gain-of-function of ORM1 suppressed and promoted NFκB activation, respectively. Finally, ORM1-enhanced NFκB-mediated inflammation development in vivo. These results suggest that an enhanced NFκB-dependent pathway following NFκB and STAT3 activation in the grafts is involved in the development of chronic allograft rejection after kidney transplantation and that ORM1 is a non-invasive candidate biomarker and possible therapeutic target for chronic kidney allograft rejection.

Robot-Assisted Radical Prostatectomy in a Second Kidney Transplant Recipient.

Background: Radical prostatectomy for de novo prostate cancer (PCa) among kidney transplant (KT) recipients (KTRs) can be challenging because of the location of the renal allograft, which may make robot-assisted radical prostatectomy (RARP) difficult to perform. In this study, we present the first case of RARP in a patient with two renal allografts in both iliac fossae. Case Presentation: A 72-year-old KTR was found to have organ-confined PCa. He had a first KT (in the right iliac fossa) 20 years ago, which he lost because of chronic allograft nephropathy, followed by a second KT (in the left iliac fossa) 8 years ago, which is now functioning well. We performed RARP with a right-nerve sparing technique. The surgical duration was 208 minutes, with an estimated blood loss of 50 mL and no intraoperative complications. The postoperative course was unremarkable. During the 21-month follow-up period, there was no incontinence or biochemical recurrence and the allograft function remained normal. Conclusion: RARP is feasible and can be performed safely in KT patients with two renal allografts in the pelvis.

A 2-mm Cutoff Value Is Reasonable and Feasible for Vascular Reconstruction in a Kidney Allograft With Multiple Arteries.

BACKGROUND: Multiple renal arteries are found in approximately 20% of living donor kidneys. We have been using an accessory artery cutoff diameter of 2 mm on preoperative computed tomography angiography to determine whether to sacrifice or reconstruct the artery. In this study, we assessed the validity and feasibility of this cutoff value. METHODS: Living related kidney recipients from 2005 to 2013 were enrolled in this retrospective study. The diameter of the accessory artery and adverse events were evaluated. The lost parenchymal volume (%) due to vascular obstruction or branch ligation was calculated by computed tomography volumetry. RESULTS: Among 128 kidney transplants, 30 donor kidneys had multiple arteries. Accessory arteries were reconstructed in 18 cases and intentionally ligated in 12 cases (mean diameter of accessory arteries, 3.10 [SD, 0.75] mm and 1.81 [SD, 0.28] mm, respectively). The mean estimated glomerular filtration rate at 1 or 12 months after transplant was not significantly different between the groups. Among reconstructed cases, 14 cases (77.8%) had good patency in the reconstructed arteries whereas the other 4 had vascular complications. The percentage of lost parenchymal volume due to ligation or occlusion of the reconstructed artery (calculated in 16 cases) was predictable with the following formula: lost volume (%) = 9.09 × diameter (mm) - 10.5 (P= .03, rs= 0.533 by Spearman rank correlation coefficient). This formula indicated that ligation of a 2-mm accessory artery leads to 7.68% loss of the renal parenchyma. CONCLUSIONS: Reconstruction using a cutoff diameter of 2 mm is worth attempting in terms of the success rate and graft function. Sacrifice of a 2-mm accessory artery leads to parenchymal loss of <8%.

Breakpoint Cluster Region-Mediated Inflammation Is Dependent on Casein Kinase II.

The breakpoint cluster region (BCR) is known as a kinase and cause of leukemia upon fusing to Abl kinase. In this study, we demonstrate that BCR associated with the α subunit of casein kinase II (CK2α), rather than BCR itself, is required for inflammation development. We found that BCR knockdown inhibited NF-κB activation in vitro and in vivo. Computer simulation, however, suggested that the putative BCR kinase domain has an unstable structure with minimal enzymatic activity. Liquid chromatography-tandem mass spectrometry analysis showed that CK2α associated with BCR. We found the BCR functions are mediated by CK2α. Indeed, CK2α associated with adaptor molecules of TNF-αR and phosphorylated BCR at Y177 to establish a p65 binding site after TNF-α stimulation. Notably, p65 S529 phosphorylation by CK2α creates a p300 binding site and increased p65-mediated transcription followed by inflammation development in vivo. These results suggest that BCR-mediated inflammation is dependent on CK2α, and the BCR-CK2α complex could be a novel therapeutic target for various inflammatory diseases.

Successful treatment with foscarnet for ganciclovir-resistant cytomegalovirus infection in a kidney transplant recipient: A case report.

Cytomegalovirus (CMV) infection is the most common infectious complication following solid organ transplantation. Ganciclovir (GCV)-resistant CMV infection may be fatal, and is difficult to treat while avoiding allograft rejection. A 31-year-old woman received a second ABO-incompatible kidney transplant, from her father. Induction therapy consisted of basiliximab and rituximab followed by maintenance immunosuppression with tacrolimus, mycophenolate mofetil, and methylprednisolone. Her CMV serostatus was D(+) /R(-) at second transplant and she received prophylactic low-dose valganciclovir (VGCV). BK polyoma virus nephropathy (BKVN) developed 7 months after transplant concurrent with CMV hepatitis and retinitis. VGCV was increased to a therapeutic dose combined with reduced immunosuppression with minimal methylprednisolone (2 mg/day) and everolimus (0.5 mg/day). However, pp65 antigenaemia continued to increase for 6 weeks. Her CMV was defined as ganciclovir (GCV)-resistant. Foscarnet was therefore administered and her CMV disease resolved within 2 weeks. Kidney allograft dysfunction developed 9 months after transplant, and graft biopsy showed tubulointerstitial injury with crystal deposition suggesting foscarnet nephrotoxicity, with no findings of BKVN or rejection. Kidney function recovered after cessation of foscarnet and the patient had good graft function 18 months after transplant. This case demonstrates the successful use of foscarnet to treat GCV-resistant CMV infection after ABO-incompatible kidney transplant complicated with BKVN, without acute allograft rejection. This case further highlights the need to establish appropriate management for CMV D(+) /R(-) patients to avoid the acquisition of GCV-resistant gene mutations.