BACKGROUND Circular RNAs (circRNAs) have recently been described as novel noncoding regulators of gene expression. They are detectable in the blood of patients with acute kidney injury. We tested whether circRNAs were present in urine and could serve as new predictors of outcome in renal transplant patients with acute rejection. METHODS A global circRNA expression analysis using RNA from urine of patients with acute T cell-mediated renal allograft rejection and control transplant patients was performed. Dysregulated circRNAs were confirmed in a cohort of 62 patients with acute rejection, 10 patients after successful antirejection therapy, 18 control transplant patients without rejection, and 13 stable transplant patients with urinary tract infection. RESULTS A global screen revealed several circRNAs to be altered in urine of patients with acute rejection. Concentrations of 2 circRNAs including hsa_circ_0001334 and hsa_circ_0071475 were significantly increased. These were validated in the whole cohort of patients. hsa_circ_0001334 was upregulated in patients with acute rejection compared with controls. Concentrations of hsa_circ_0001334 normalized in patients with acute rejection following successful antirejection therapy. hsa_circ_0001334 was associated with higher decline in glomerular filtration rate 1 year after transplantation. CONCLUSIONS CircRNA concentrations are significantly dysregulated in patients with acute rejection at subclinical time points. Urinary hsa_circ_0001334 is a novel biomarker of acute kidney rejection, identifying patients with acute rejection and predicting loss of kidney function.

Background. Before kidney transplantation, donors and recipients are routinely screened for viral pathogens using specific tests. Little is known about unrecognized viruses of the urinary tract that potentially result in transmission. Using an open metagenomic approach, we aimed to comprehensively assess virus transmission in living-donor kidney transplantation.Methods. Living kidney donors and their corresponding recipients were enrolled at the time of transplantation. Follow-up study visits for recipients were scheduled 4-6 weeks and 1 year thereafter. At each visit, plasma and urine samples were collected and transplant recipients were evaluated for signs of infection or other transplant-related complications. For metagenomic analysis, samples were enriched for viruses, amplified by anchored random polymerase chain reaction (PCR), and sequenced using high-throughput metagenomic sequencing. Viruses detected by sequencing were confirmed using real-time PCR.Results. We analyzed a total of 30 living kidney donor and recipient pairs, with a follow-up of at least 1 year. In addition to viruses commonly detected during routine post-transplant virus monitoring, metagenomic sequencing detected JC polyomavirus (JCPyV) in the urine of 7 donors and their corresponding recipients. Phylogenetic analysis confirmed infection with the donor strain in 6 cases, suggesting transmission from the transplant donor to the recipient, despite recipient seropositivity for JCPyV at the time of transplantation.Conclusions. Metagenomic sequencing identified frequent transmission of JCPyV from kidney transplant donors to recipients. Considering the high incidence rate, future studies within larger cohorts are needed to define the relevance of JCPyV infection and the donor's virome for transplant outcomes.

Background and objectivesThe general rule that every active malignancy is an absolute contraindication for kidney transplantation is challenged by kidney failure patients diagnosed with active surveillance-eligible prostate cancer during pretransplantation workup. Interdisciplinary treatment teams therefore often face the challenge of balancing the benefits of early kidney transplantation and the risk of metastatic progression. Hence, we compared the quality-adjusted life expectancy of different management strategies in kidney failure patients diagnosed with active surveillance-eligible prostate cancer during pretransplantation workup.Design, setting, participants, & measurementsA discrete event simulation model was developed on the basis of a systematic literature search, clinical guidelines, and expert opinion. After model validation and calibration, we simulated four management strategies in a hypothetical cohort of 100,000 patients: Definitive treatment (surgery or radiation therapy) and listing after a waiting period of 2 years, definitive treatment and immediate listing, active surveillance and listing after a waiting period of 2 years, and active surveillance and immediate listing. Individual patient results (quality-adjusted life years; QALYs) were aggregated into strategy-specific means (± SEs).ResultsActive surveillance and immediate listing yielded the highest amount of quality-adjusted life expectancy (6.97 ± 0.01 QALYs) followed by definitive treatment and immediate listing (6.75 ± 0.01 QALYs). These two strategies involving immediate listing not only outperformed those incorporating a waiting period of 2 years (definitive treatment: 6.32 ± 0.01 QALYs; active surveillance: 6.59 ± 0.01 QALYs) but also yielded a higher proportion of successfully performed transplantations (72% and 74% versus 56% and 59%), with less time on hemodialysis on average (4.02 and 3.81 years versus 4.80 and 4.65 years).ConclusionsAmong kidney failure patients diagnosed with active surveillance-eligible prostate cancer during pretransplantation workup, the active surveillance and immediate listing strategy outperformed the alternative management strategies from a quality of life expectancy perspective, followed by definitive treatment and immediate listing.