Author Correction: Tubular cell and keratinocyte single-cell transcriptomics applied to lupus nephritis reveal type I IFN and fibrosis relevant pathways.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Tubular cell and keratinocyte single-cell transcriptomics applied to lupus nephritis reveal type I IFN and fibrosis relevant pathways.

The molecular and cellular processes that lead to renal damage and to the heterogeneity of lupus nephritis (LN) are not well understood. We applied single-cell RNA sequencing (scRNA-seq) to renal biopsies from patients with LN and evaluated skin biopsies as a potential source of diagnostic and prognostic markers of renal disease. Type I interferon (IFN)-response signatures in tubular cells and keratinocytes distinguished patients with LN from healthy control subjects. Moreover, a high IFN-response signature and fibrotic signature in tubular cells were each associated with failure to respond to treatment. Analysis of tubular cells from patients with proliferative, membranous and mixed LN indicated pathways relevant to inflammation and fibrosis, which offer insight into their histologic differences. In summary, we applied scRNA-seq to LN to deconstruct its heterogeneity and identify novel targets for personalized approaches to therapy.

Effect of glecaprevir/pibrentasvir on weight-adjusted tacrolimus trough/dose ratios in heart and kidney transplant recipients.

OBJECTIVE: The pharmacokinetic implications of direct-acting antiviral (DAA) use on tacrolimus posttransplant are unknown. This study sought to investigate the effects of glecaprevir/pibrentasvir (G/P), a CYP3A4 substrate and inhibitor, on weight-adjusted tacrolimus (FK) trough/dose ratio (T/D) following heart or kidney transplantation. MATERIAL AND METHODS: This was a single-center, retrospective analysis of hepatitis C virus (HCV) viremic donors to HCV negative heart or kidney transplant recipients who received 12 weeks of G/P therapy. Weight-adjusted T/D was assessed while patients were at steady-state before, during, and after G/P treatment. Forty-one HCV negative recipients (three heart, 38 kidney) were evaluated. RESULTS: The weight-adjusted T/D significantly increased during G/P treatment (119.31, IQR 88-173.8) compared to before G/P treatment (67.4, IQR 53.4-115.9) (p < 0.01), but decreased after completion of treatment (90.1, IQR 52.9-122.7) (p < 0.01). There was no difference in weight-adjusted T/D before and after G/P treatment (p = 0.42). Four patients experienced acute rejection. CONCLUSION: Initiation of G/P in heart or kidney transplant recipients induces a reversible change in tacrolimus metabolism. A 33%-50% tacrolimus dose reduction may be considered at the time of G/P initiation. Regardless of tacrolimus dose adjustment, tacrolimus trough levels should be monitored 3 days after initiation of G/P. No clear relationship between HCV viremic organ transplantation and rejection risk was found. Larger studies are warranted to validate these findings.

Commercial insurance delays direct-acting antiviral treatment for hepatitis C kidney transplantation into uninfected recipients.

INTRODUCTION: The advent of direct-acting antivirals (DAAs) has created an avenue for transplantation of hepatitis C virus (HCV)-infected donors into uninfected recipients (D+/R-). The donor transmission of HCV is then countered by DAA administration during the post-operative period. However, initiation of DAA treatment is ultimately dictated by insurance companies. METHODS: A retrospective chart review of 52 D+/R- kidney recipients who underwent DAA treatment post-transplant was performed. Patients were grouped according to their prescription coverage plans, managed by either commercial or government pharmacy benefit managers (PBMs). RESULTS: Thirty-nine patients had government PBMs and 13 had commercial PBMs. Demographics were similar between the two groups. All patients developed HCV viremia, but cleared the virus after treatment with DAA. Patients with government PBMs were treated earlier compared to those with commercial PBMs (11 days vs 26 days, P = .01). Longer time to DAA initiation resulted in higher peak viral loads (ß = 0.39, R2  = .15, P = .01) and longer time to HCV viral load clearance (ß = 0.41, R2  = .17, P = .01). CONCLUSIONS: D+/R- transplantation offers patients an alternative strategy to increase access. However, treatment can be profoundly delayed by a third-party payer authorization process that may be subjecting patients to unnecessary risks and worsened outcomes.

Transplantation of viral-positive hepatitis C-positive kidneys into uninfected recipients offers an opportunity to increase organ access.

The advent of direct-acting antivirals (DAAs) has provided the impetus to transplant kidneys from hepatitis C virus-positive donors into uninfected recipients (D+/R-). Thirty D+/R- patients received DAA treatment. Sustained virologic response (SVR12) was defined as an undetectable viral load in 12 weeks after treatment. An age-matched cohort of uninfected donor and recipient pairs (D-/R-) transplanted during same time period was used for comparison. The median day of viral detection was postoperative day (POD) 2. The detection of viremia in D+/R- patients was 100%. The initial median viral load was 531 copies/µL (range: 10-1 × 108 copies/µL) with a median peak viral load of 3.4 × 105 copies/µL (range: 804-1.0 × 108 copies/µL). DAAs were initiated on median POD 9 (range: 5-41 days). All 30 patients had confirmed SVR12. During a median follow-up of 10 months, patient and graft survival was 100%, and acute rejection was 6.6% with no major adverse events related to DAA treatment. Delayed graft function was significantly decreased in D+/R- patients as compared to the age-matched cohort (27% vs 60%; P = .01). D+/R- transplantation offers patients an alternative strategy to increase access.

Improving pancreas graft utilization through importation.

BACKGROUND: We analyze our outcomes utilizing imported allografts as a strategy to shorten wait list time for pancreas transplantation. METHODS: This is an observational retrospective cohort of 26 recipients who received either a locally procured (n = 16) or an imported pancreas graft (n = 10) at our center between January 2014 and May 2017. Wait list times of this cohort were compared to UNOS Region 9 (New York State and Western Vermont). Hospital financial data were also reviewed to analyze the cost-effectiveness of this strategy. RESULTS: Imported pancreas grafts had significantly increased cold ischemia times (CIT) and peak lipase (PL) levels compared to locally procured grafts (CIT 827 vs 497 minutes; P = .001, PL 563 vs 157 u/L; P = .023, respectively). There were no differences in graft or patient survival. The median wait time was significantly lower for simultaneous kidney-pancreas transplants at our center (518 days, n = 21) compared to Region 9 (1001 days, n = 65) P = .038. Despite financial concerns, the cost of transport for imported grafts was offset by lower standard acquisition costs. CONCLUSIONS: Imported pancreas grafts may be a cost-effective strategy to increase organ utilization and shorten wait times in regions with longer waiting times.

"Resuscitation" of marginal liver allografts for transplantation with machine perfusion technology.

As the rate of medically suitable donors remains relatively static worldwide, clinicians have looked to novel methods to meet the ever-growing demand of the liver transplant waiting lists worldwide. Accordingly, the transplant community has explored many strategies to offset this deficit. Advances in technology that target the ex vivo "preservation" period may help increase the donor pool by augmenting the utilization and improving the outcomes of marginal livers. Novel ex vivo techniques such as hypothermic, normothermic, and subnormothermic machine perfusion may be useful to "resuscitate" marginal organs by reducing ischemia/reperfusion injury. Moreover, other preservation techniques such as oxygen persufflation are explored as they may also have a role in improving function of "marginal" liver allografts. Currently, marginal livers are frequently discarded or can relegate the patient to early allograft dysfunction and primary non-function. Bench to bedside advances are rapidly emerging and hold promise for expanding liver transplantation access and improving outcomes.

Early acceptance of renal allografts in mice is dependent on foxp3(+) cells.

Mouse renal allografts have a remarkable ability to promote acceptance across full major histocompatibility complex incompatibilities in certain strain combinations without immunosuppression. The mechanism is unknown but is believed to involve immunoregulation. This study tests whether Foxp3(+) T-regulatory cells are responsible in the early phase of graft acceptance, using B6.Foxp3(DTR) mice that express diphtheria toxin receptor (DTR) in Foxp3(+) cells. The administration of DT to B6.Foxp3(DTR) recipients with accepted DBA/2 kidneys, 3 weeks to 3 months after transplantation, caused a marked depletion of Foxp3 cells and triggered acute cellular rejection, manifested by a sudden increase in blood urea nitrogen within a week. None of the controls showed an increase in blood urea nitrogen, including DT-treated B6 wild-type recipients of DBA/2 kidneys or B6.Foxp3(DTR) recipients of isografts. Accepted DBA/2 allografts showed prominent lymphoid sheaths around arteries containing numerous CD3(+)Foxp3(+) cells, CD4(+) cells, dedritic cells, and B cells, which was independent of CCR4. The lymphoid sheaths disintegrate after Foxp3 depletion, accompanied by widespread CD8 interstitial mononuclear inflammation, tubulitis, and endarteritis. The Foxp3 depletion caused an increased frequency of donor-reactive cells in the spleen by interferon (IFN) γ enzyme-linked immunosorbent spot (ELISPOT) assays and increased expression of the maturation markers, CD86 and IA(b), on dendritic cells in the spleen and kidney. We conclude that Foxp3(+) cells are needed to maintain acceptance of major histocompatibility complex-incompatible renal allografts in the first 3 months after transplantation and may act by inhibiting DC maturation.

Suppressive regulatory T cell activity is potentiated by glycogen synthase kinase 3{beta} inhibition.

The mechanism by which regulatory T (Treg) cells suppress the immune response is not well defined. A recent study has shown that ß-catenin prolongs Treg cell survival. Because ß-catenin is regulated by glycogen synthase kinase 3ß (GSK-3ß)-directed phosphorylation, we focused on GSK-3ß and the role it plays in Treg cell function. Inhibition of GSK-3ß led to increased suppression activity by Treg cells. Inhibitor-treated Treg cells exhibited prolonged FoxP3 expression and increased levels of ß-catenin and of the antiapoptotic protein Bcl-xL. Systemic administration of GSK-3ß inhibitor resulted in prolonged islet survival in an allotransplant mouse model. Our data suggest that GSK-3ß could be a useful target in developing strategies designed to increase the stability and function of Treg cells for inducing allotransplant tolerance or treating autoimmune conditions.

Risks and Benefits of Kidney Transplantation during the COVID-19 Pandemic: Transplant or Not Transplant?

COVID-19 has significantly affected the transplant community, by leading to decreased transplant activity and increased waiting list time. As expected, COVID-19 causes substantial mortality in both ESKD and kidney transplant populations. This is due to underlying CKD and a high prevalence of comorbid conditions, such as diabetes mellitus, hypertension, and cardiovascular disease in this group. Transplant programs have faced the difficult decision of weighing the risks and benefits of transplantation during the pandemic. On one hand, there is a risk of COVID-19 exposure leading to infection while patients are on maximum immunosuppression. Alternatively, there are risks of delaying transplantation, which will increase waitlist times and may lead to waitlist-associated morbidity and mortality. Cautious and thoughtful selection of both the recipient's and donor's post-transplant management has been required during the pandemic, to mitigate the risk of morbidity and mortality associated with COVID-19. In this review article, we aimed to discuss previous publications related to clinical outcomes of COVID-19 disease in kidney transplant recipients, patients with ESKD on dialysis, or on the transplant waiting list, and the precautions transplant centers should take in decision making for recipient and donor selection and immunosuppressive management during the pandemic. Nevertheless, transplantation in this milieu does seem to be the correct decision, with careful patient and donor selection and safeguard protocols for infection prevention. Each center should conduct risk assessment on the basis of the patient's age and medical comorbidities, waitlist time, degree of sensitization, cold ischemia time, status of vaccination, and severity of pandemic in their region.

Native kidney small renal masses in patients with kidney transplants: Does chronic immunosuppression affect tumor biology?

INTRODUCTION: We compared clinicopathological characteristics and outcomes of radical nephrectomy (RN) for small renal masses (SRM) in patients with end-stage renal disease (ESRD) before or after transplant at a high-volume urologic and transplant center. METHODS: We performed a retrospective review of patients with ESRD (glomerular filtration rate [GFR] <15 mL/min) who underwent RN for suspected malignant SRM from 2000-2018. Group 1 consisted of patients who underwent RN after transplant; group 2 underwent RN prior to transplant, and group 3 underwent RN without subsequent transplant. Dominant tumor size and histopathological characteristics, recurrence, and survival outcomes were compared between groups. Chi-squared and Mann-Whitney U tests were used to compare categorical and continuous baseline and histopathologic characteristics, respectively. Univariate analysis and log rank test were used to compare RCC recurrence rates. RESULTS: We identified 34 nephrectomies in group 1, 27 nephrectomies in group 2, and 70 nephrectomies in group 3. Median time from transplant to SRM radiological diagnosis in group 1 was 87 months, and three months from diagnosis to nephrectomy for all groups. There were no statistically significant differences between pathological dominant mass size, histological subtype breakdown, grade, or stage between the groups. Rates of benign histology were similar between the groups. Univariate analysis did not reveal a statistically significant difference in recurrence-free survival between the groups (p=0.9). CONCLUSIONS: Patients undergoing nephrectomy before or after transplant for SRM have similar indolent clinicopathological characteristics and low recurrence rates. Our results suggest that chronic immunosuppression does not adversely affect SRM biology.

High terminal creatinine donors should not preclude simultaneous kidney and pancreas transplantation.

BACKGROUND: Simultaneous pancreas and kidney transplantation (SPK) in the setting of end-stage renal disease offers unmatched outcomes in insulin dependent diabetic patients. Donor pool expansion through the transplantation of kidneys with acute kidney injury (AKI) is controversial. METHODS: 59 SPK transplants were classified by presence of donor AKI, defined as donor terminal creatinine ≥ 1.5x the initial creatinine or donor terminal creatinine > 4.0 mg/dL. Endpoints included graft and patient survival, delayed graft function (DGF), serum creatinine, glomerular filtration rate (GFR), Hemoglobin A1c (HbA1c) and acute rejection. RESULTS: The donor AKI group (n = 35) had significantly higher rates of DGF (38 v. 9%, p = 0.01). There was no difference in creatinine or GFR at 1, 3, 6 and 12 months. HbA1c was comparable at 3, 6 and 12 months. There was no significant difference in the percentage of patients that required anti-diabetic agents after transplant (14 v. 4%, p = 0.56). CONCLUSIONS: We observed increased rates of DGF in SPK recipients with donor AKI. However, equivalent outcomes of pancreas and kidney function in both groups were observed.

The use of LCP-Tacrolimus (Envarsus XR) in simultaneous pancreas and kidney (SPK) transplant recipients.

BACKGROUND: Extended release LCP-tacrolimus (LCPT) allows once-daily dosing in transplant recipients. The improved bioavailability may be beneficial for simultaneous pancreas-kidney recipients (SPK). METHODS: This is a study of 39 SPK recipients on standard immediate-release tacrolimus (IR-TAC, n = 21) or LCPT (n = 18). Coefficient of variability (CV = 100∗standard deviation/mean) was calculated to assess drug levels. Hemoglobin A1c (HbA1c), tacrolimus and creatinine levels were measured postoperatively. RESULTS: There was no difference in tacrolimus CV in the IR-TAC and LCPT groups at 1 month or 3 months postoperatively; however, a greater difference was observed at 1 year (41.0 vs. 33.1%; p = 0.19). There were six episodes of acute rejection in the IR-TAC group compared to zero episodes in the LCPT group (p = 0.01). HbA1c was significantly higher in the IR-TAC group compared to LCPT at 3 (5.5 vs. 4.9%, p = 0.01), 6 (5.6 vs. 4.9%, p = 0.01) and 12 months (5.8 vs. 5.1%, p = 0.07). CONCLUSIONS: Significantly lower rates of rejection were observed in patients receiving LCPT. The once daily dosing may facilitate medication adherence and result in improved long-term outcomes.

Preoperative C-Peptide Predicts Weight Gain After Pancreas Transplantation.

BACKGROUND: Transplant recipients are susceptible to cardiovascular complications, obesity, and increased insulin resistance after transplant. Here we assess weight gain in diabetic recipients after pancreas transplantation. METHODS: This is a single-center study of 32 simultaneous pancreas and kidney and 5 pancreas after kidney transplant recipients from 2014 to 2018. Starting C-peptide levels ≤ 0.1 ng/mL were used to denote insulin nondetectability (n = 25) and C-peptide levels > 0.1 ng/mL as insulin detectability (n = 12). Hemoglobin A1c, body mass index (BMI), and weight following transplantation were assessed. RESULTS: Hemoglobin A1c at 1 year was 5.9% in the insulin nondetectable recipients and 5.6% in the insulin detectable group (P = .56). Average BMI after transplant was higher in the insulin detectable group 28.6 versus 24.4 kg/m2 (P = .03) despite no difference in starting BMIs (24.9 versus 24.0 kg/m2, P = .42). The insulin detectable group also had a larger percentage weight change from their starting weight 13.1% versus 0.9 % at 1 year (P = .02). Linear regression demonstrated that starting C-peptide was a significant predictor of weight gain posttransplant. CONCLUSIONS: Patients with elevated C-peptides at time of transplant are susceptible to rapid weight gain postoperatively. These patients may benefit from aggressive nutritional management.

Transplant surgery enters a new era: Increasing immunosuppressive medication adherence through mobile apps and smart watches.

The high rate of immunosuppressive medication non-adherence in transplant recipients demands the search for a solution that targets modifiable risk factors and incorporates mobile health technology to better engage and educate patients. Kidney transplant recipients (kidneys alone or multi-organ) were randomized to receive a mobile app known as Transplant Hero, both the app and a smart watch, or neither. The coefficient of variability (CV) of tacrolimus levels was measured at one and three months. No statistically significant differences in CV levels were observed between the three groups at either one or three months. Although mobile health apps are a promising strategy for increasing medication adherence, further research is required to determine how to best use this technology.

Young donors with severe acute kidney injury offer an opportunity to expand the donor pool.

BACKGROUND: This study assessed our experience transplanting kidneys from young donors with severe acute kidney injury. METHODS: We performed a single center retrospective analysis of 315 kidney transplants between 1/1/2014-12/31/2016. Donor kidneys were classified according to the Acute Kidney Injury Network (AKIN) criteria. A case-matched cohort was created using recipient age, history of diabetes, donor specific antibody, donor age and donor after cardiac death. Primary endpoints were graft function measured by eGFR at 90 days and at 1-year. RESULTS: Stage 3 AKIN recipients had significantly greater eGFR at one year (63.9 ml/min v. 51.2 ml/min, p < 0.001) compared to those with Stage 0 AKIN. This difference was abrogated when compared to a case matched cohort (eGFR at 90 days or 1 year; p > 0.05). Donor and recipient characteristics on eGFR at 1 year were analyzed using linear and logistic regression. Only donor age had a significant impact on recipient eGFR. CONCLUSIONS: Donor kidneys with severe acute injury can achieve optimal 1-year outcomes. Donor age is the most significant predictor of eGFR >45 ml/min after transplant.