Subthreshold rejection activity in many kidney transplants currently classified as having no rejection.

Most kidney transplant patients who undergo biopsies are classified as having no rejection based on consensus thresholds. However, we hypothesized that because these patients have normal adaptive immune systems, T cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR) may exist as subthreshold activity in some transplants currently classified as no rejection. To examine this question, we studied genome-wide microarray results from 5086 kidney transplant biopsies (4170 patients). An updated archetypal analysis designated 56% of biopsies as no rejection. Subthreshold molecular TCMR and/or ABMR activity molecular activity was detectable as elevated classifier scores in many biopsies classified as no rejection, with ABMR activity in many TCMR biopsies and TCMR activity in many ABMR biopsies. In biopsies classified as no rejection histologically and molecularly, molecular TCMR classifier scores correlated with increases in histologic TCMR features and molecular injury, lower eGFR, and higher risk of graft loss, and molecular ABMR activity correlated with increased glomerulitis and donor-specific antibody. No rejection biopsies with high subthreshold TCMR or ABMR activity had a higher probability of having TCMR or ABMR respectively diagnosed in a future biopsy. We conclude that many kidney transplant recipients have unrecognized subthreshold TCMR or ABMR activity, with significant implications for future problems.

Management of kidney transplant recipients for primary care practitioners.

Patients with kidney transplants have a significant co-morbidity index, due to a high number of pre-existing conditions and use of immunosuppression medications. These patients are at higher risk of developing conditions such as hypertension, dyslipidemia, post-transplant diabetes, cardiovascular events, and anemia. Moreover, they are particularly susceptible to infections such as urinary tract infections or pyelonephritis, cancers, and gastrointestinal complications such as diarrhea, which in turn may be attributed to medication adverse effects or infectious causes. Along with these concerns, meticulous management of electrolytes and allograft function is essential. Prior to prescribing any new medications, it is imperative to exercise caution in identifying potential interactions with immunosuppression drugs. This review aims to equip primary care practitioners to address these complex issues and appropriate methods of delivering care to this rapidly growing highly susceptible group.

Principles of Immunosuppression in the Management of Kidney Disease: Core Curriculum 2022.

The management of immunosuppression utilized in glomerular diseases requires highly nuanced care. Timely recognition and management of these disorders is essential to mitigate the extent of kidney damage. This involves being cognizant of the various classes of immunosuppression, which includes alkylating agents, antimetabolites, calcineurin inhibitors, anti-CD20 therapy, complement inhibitors, corticosteroids, and intravenous immunoglobulin. The mechanisms of action of these drugs, along with associated pharmacokinetics and pharmacodynamics, facets of monitoring, and adverse effects are important aspects with which nephrologists are required to be well versed. In addition, an understanding of therapeutic decisions such as induction and maintenance regimens in the setting of glomerular disease and alteration based on trajectory of disease and subsequent response is imperative. The overarching principle of these strategies of immunosuppression is to achieve a balance of disease mitigation without exposure to inadvertent harm. Special groups such as pregnant women, elderly patients, and patients treated with dialysis are especially susceptible to immunosuppression and thus need highly weighed therapeutic strategies and enhanced surveillance of adverse effects.

Advances in Understanding of Pathogenesis and Treatment of Immune-Mediated Kidney Disease: A Review.

There continues to be rapid advancement in our understanding of the pathogenesis of immune-mediated kidney disease. This progress has culminated in the development of multiple therapeutic agents that have consistently improved renal and patient outcomes. The focus of this review is to discuss these recent advancements in immune-mediated kidney disease via the lens of direct and indirect immune-mediated mechanisms. In the direct immune-mediated disease, recently described antigens in anti-glomerular basement membrane (GBM) disease and membranous nephropathy are discussed, along with new therapeutic regimens in membranous nephropathy and focal segmental glomerulosclerosis. From an indirect immune-mediated disease standpoint, recent pivotal trials in antineutrophil cytoplasmic antibody vasculitis, lupus nephritis, and IgA nephropathy are examined from a real-world practice perspective. New molecular pathways in various disorders of alternate complement pathway are described, which in turn have led to development of various experimental therapies. In addition, pivotal and ongoing therapeutic trials in the aforementioned diseases are presented.

Donor Derived Cell Free DNA in Kidney Transplantation: The Circa 2020-2021 Update.

The routine surveillance of kidney transplant allografts has relied on imperfect non-invasive biomarkers such as creatinine and urinary indices, while the gold standard allograft biopsy is associated with risk of bleeding, organ injury and sampling errors. Donor derived cell free DNA (dd-cfDNA) is being employed as a biomarker that addresses limitations of these surveillance methods, albeit has inherent drawbacks. This review provides an update on the enhanced understanding of dd-cfDNA and its expanded use beyond the conventional indication of detecting allograft rejection.

Donor-Derived Cell-Free DNA in Kidney Transplantation: Origins, Present and a Look to the Future.

Since its first detection in 1948, donor-derived cell-free DNA (dd-cfDNA) has been employed for a myriad of indications in various medical specialties. It has had a far-reaching impact in solid organ transplantation, with the most widespread utilization in kidney transplantation for the surveillance and detection of allograft rejection. The purpose of this review is to track the arc of this revolutionary test-from origins to current use-along with examining challenges and future prospects though the lens of transplant nephrology.

Ten-year outcome of Eculizumab in kidney transplant recipients with atypical hemolytic uremic syndrome- a single center experience.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) can result in severe kidney dysfunction, secondary to thrombotic microangiopathy. Eculizumab has been used to treat this disorder, and has resulted in favourable outcomes in both, native and transplanted kidneys. There is limited long term follow up data in kidney transplant recipients (KTRs) who received prevention and treatment with Eculizumab. We report our long term follow up data from our center to address safety and efficacy of this therapy in KTRs. METHODS: We performed a retrospective analysis of KTRs between January 2009 and December 2018. Clinical diagnosis of aHUS established with presence of thrombotic microangiopathy, acute kidney injury, absence of alternate identifiable etiology. We reviewed clinical data, including genetic testing for complement factor mutations, post-transplant course, and response to therapy including therapeutic and prophylactic use of eculizumab. RESULTS: Nineteen patients with aHUS received a total of 36 kidney transplants; 10 of them had 2 or more prior kidney transplants. Median age at time of last transplant was 37 years (range 27-59), 72% were female (n = 14), 78% Caucasian (n = 15), with 61% had live donor transplant (n = 12) as the last transplant. Eculizumab prophylaxis was given to 10/19 (56%) at the time of transplantation, with no aHUS recurrence during the follow up. Median duration of follow up was 46 (range 6-237) months. Mean estimated glomerular filtration rate (eGFR) at the time of last follow up was 59.5 ml/min/m2. No infections secondary to encapsulated organisms or other major infectious complications occurred during the follow up. CONCLUSIONS: Eculizumab prophylaxis is safe and effective in KTRs with aHUS. Long term follow up demonstrates that it may be possible to discontinue prophylaxis carefully in selected patients with no evidence of complement mutations.

The COVID-19 nephrology compendium: AKI, CKD, ESKD and transplantation.

The pandemic of coronavirus disease 2019 (CoVID-19) has been an unprecedented period. The disease afflicts multiple organ systems, with acute kidney injury (AKI) a major complication in seriously ill patients. The incidence of AKI in patients with CoVID-19 is variable across numerous international studies, but the high incidence of AKI and its associated worse outcomes in the critical care setting are a consistent finding. A multitude of patterns and mechanisms of AKI have been elucidated, and novel strategies to address shortage of renal replacement therapy equipment have been implemented. The disease also has had consequences on longitudinal management of patients with chronic kidney disease and end stage kidney disease. Kidney transplant recipients may be especially susceptible to CoVID-19 as a result of immunosuppression, with preliminary studies demonstrating high mortality rates. Increased surveillance of disease with low threshold for testing and adjustment of immunosuppression regimen during acute periods of illness have been recommended.

Sequential Therapy for Remission Induction in Severe Antineutrophil Cytoplasmic Autoantibody-Associated Glomerulonephritis.

BACKGROUND: The introduction of combination therapy with glucocorticoids (GC) and cyclophosphamide (CYC) or rituximab (RTX) has resulted in remission rates exceeding 90% in patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV). However, early treatment-related mortality remains a major concern and has driven the search for safer induction regimens exploring minimization or avoidance of GC and CYC. Most trials have excluded patients with severe renal disease. We report the outcomes of AAV patients with severe renal disease treated with sequential therapy (ST) starting with (GC) and oral (CYC) followed by transition to (RTX). METHODS: Patients with new or relapsing severe AAV who presented with severe renal disease and/or rapidly progressive glomerulonephritis (RPGN) were identified. RPGN was defined as at least a 20% decrease in estimated glomerular filtration rate (eGFR) over a 2-week period along with hematuria and proteinuria. Induction treatment included pulse (GC) for 3 days followed by oral prednisone tapered to 5 mg by month 6, oral (CYC) adjusted for GFR until improvement in Birmingham Vasculitis Activity Score (BVAS), and serum creatinine at which point (CYC) was stopped and induction dose of (RTX) was given. Use of plasmapheresis (PLEX) was allowed. The primary outcome was complete remission defined as BVAS of zero by 6 months. Descriptive data are presented as median with range and mean with SD. RESULTS: Nine patients met the inclusion criteria. Median age at diagnosis was 63 years. The majority were females, myeloperoxidase ANCA positive, and had a new diagnosis. The mean nadir (SD) eGFR was 12 (5) with 3 requiring dialysis. The median BVAS at the time of diagnosis was 15. All patients received ST and 3 received PLEX. The median exposure to oral CYC was 35 days. The mean (SD) eGFR and median BVAS were 26 (12) and 3, respectively, at the time of switching to RTX. The median prednisone dose at 6M was 5 mg. The median follow-up was 44 months. All patients achieved remission. One patient with relapsing disease reached ESRD. The mean (SD) eGFR in the remaining 8 patients at last FU was 37 (27), and the mean (SD) eGFR rise at 1 year was 26 (25). Adverse events included 2 patients with pneumonia and 3 with bone marrow suppression. There were no deaths. CONCLUSION: ST with GC and CYC followed by RTX is effective for in AAV patients with severe renal disease. Therapy-related adverse events are comparable to other studies, and further modification in ST with decrease in GC dosage should be explored.

ANCA-associated vasculitis in scleroderma: A renal perspective
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AIMS: Overlap syndrome of ANCA-associated vasculitis (AAV) and scleroderma (SSc) is rare with conflicting data on renal outcomes. We describe the clinical characteristics and treatment outcome of ANCA-associated glomerulonephritis (AAG) in SSc patients followed at a single center. MATERIALS AND METHODS: We conducted a retrospective study of 3,570 patients in our SSc database to identify SSc patients who subsequently developed AAV with renal involvement. Patient demographics, serology, renal function, renal histology, and treatment outcomes were assessed. RESULTS: Of the 3,570 patients, we identified 7 patients who developed acute glomerulonephritis, and all were ANCA positive. The mean age at SSc diagnosis was 47 years, 4 patients were female, and 6 had diffuse SSc. Anti-nuclear antibody (ANA) was positive in all. Mean time of onset of AAV from time of diagnosis of SSc was 6 years, and all were myeloperoxidase (MPO) positive. Patients presented with hematuria, proteinuria, with or without rise in serum creatinine, and all patients had biopsy-proven crescentic glomerulonephritis. One patient required dialysis at presentation. Five patients were treated with cyclophosphamide and steroids, and 2 were treated with rituximab and steroids. Of the 7 patients, 4 did not receive maintenance immunosuppression. Three patients died, and 1 of them experienced relapse with fulminant alveolar hemorrhage. CONCLUSION: AAG in SSc is rare, with disease manifestation and course similar to that of AAV. This case series demonstrates that disease remission can be achieved with standard induction therapy. Vasculitis relapse can occur, and similar to idiopathic AAV, maintenance immunosuppression should be initiated to maintain remission.
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Outcomes and management of kidney transplant recipients with Fabry disease: a review.

Fabry disease is an X-linked inheritable lysosomal storage disease caused by various mutations of the galactosidase α gene resulting in α-galactosidase deficiency. Chronic kidney disease (CKD) is one of the most significant consequences of Fabry disease, with risk of end-stage kidney disease (ESKD) in this population. Like for other patients with ESKD, kidney transplant is the optimal treatment for Fabry disease patients with ESKD. However, enzyme replacement therapy and newer Fabry disease treatments remain important to mitigate other end organ damage such as cardiomyopathy post transplantation. This review is a primer on Fabry disease, which examines the outcomes of disease in the context of kidney transplant prior to, and during, the enzyme replacement treatment era, medical treatment of kidney transplant recipients with Fabry disease, and progress in screening studies.

Twenty years in the making: tolerance in a living-related kidney transplant recipient.

Kidney transplant recipients require lifelong immunosuppression to prevent graft rejection. However, immunosuppression is associated with adverse effects. A minority of kidney transplant recipients can be weaned off immunosuppression and maintain their graft function, a situation referred to as "functional or operational tolerance". We describe a case of a 70-year-old man who received a haploidentical hematopoietic cell transplant for lymphoma 22 years before receiving a kidney transplant from the same donor and was weaned off all immunosuppression by four months post-transplant. Tolerance was present, and there has been no graft rejection or graft vs. host disease. This case demonstrates successful long-term hematopoietic chimerism and functional tolerance after receiving a kidney transplant from the same donor.

Pathophysiology of Rejection in Kidney Transplantation.

Kidney transplantation has been the optimal treatment for end-stage kidney disease for almost 70 years, with increasing frequency over this period. Despite the prevalence of the procedure, allograft rejection continues to impact transplant recipients, with consequences ranging from hospitalization to allograft failure. Rates of rejection have declined over time, which has been largely attributed to developments in immunosuppressive therapy, understanding of the immune system, and monitoring. Developments in these therapies, as well as an improved understanding of rejection risk and the epidemiology of rejection, are dependent on a foundational understanding of the pathophysiology of rejection. This review explains the interconnected mechanisms behind antibody-mediated and T-cell-mediated rejection and highlights how these processes contribute to outcomes and can inform future progress.

Measures to Increase Immunogenicity of SARS-CoV-2 Vaccines in Solid Organ Transplant Recipients: A Narrative Review.

Purpose of review: To review the data on the immunogenicity of COVID-19 vaccines, administered by different strategies, in solid organ transplant recipients (SOTRs). Recent findings: COVID-19 booster vaccines were given to SOTRs as a widespread practice in many transplant centers, mostly as the third and/or fourth dose in an extended vaccine series, with a significantly improved humoral response compared with the initial two-dose scheme. However, one-third of SOTRs remained unresponsive, despite these boosters. Next steps: Vaccination with standard dosing remains the most feasible strategy for attaining protection against COVID-19. Additional booster doses and temporarily holding or reducing mycophenolate mofetil/mycophenolic acid may provide immunogenicity to vaccines, according to recent studies demonstrating some efficacy with these measures. Preexposure prophylaxis with monoclonal antibodies showed benefit in immunocompromised patients but is no longer recommended by the National Institutes of Health (NIH) due to diminished efficacy against Omicron and recent variants. Screening for the presence and titers of SARS-CoV-2-specific antibodies in SOTRs is not recommended in most clinical settings. T cell-based techniques are needed to evaluate vaccine efficacy and risk of infection. As SARS-CoV-2 continues to evolve, new vaccines based on conservative protein component/complexes of the COVID virus, in addition to its spike protein, are warranted to offer prolonged protection.

Master protocol to assess the long-term safety in kidney transplant recipients who previously received Medeor's cellular immunotherapy products: the MDR-105-SAE.

BACKGROUND: Immunosuppression in transplantation continues to be associated with a multitude of adverse effects. Induction of immune tolerance may be a viable strategy to reduce dependence on immunosuppression. Various trials are currently underway to assess the efficacy of this strategy. However, long-term safety data for these immune tolerance regimes has yet to be established. METHODS/DESIGN: At the completion of primary follow-up of various Medeor kidney transplant studies, subjects receiving cellular immunotherapy products will be followed annually as per protocolized schedule for up to an additional 84 months (7 years) to evaluate long-term safety. Long-term safety will be assessed by summarizing incidence of serious adverse events, adverse events leading to study withdrawal and hospitalization rates. DISCUSSION: This extension study will be an important step in evaluating safety issues pertaining to immune tolerance regimens, long-term effects of which are largely unknown. These data are essential for furthering an unrealized goal of kidney transplantation- graft longevity without the adverse effects from long-term immunosuppression. The study design utilizes the methodology of a master protocol, wherein multiple therapies can be assessed simultaneously with accompanied gathering of long-term safety data.

BK Virus Nephropathy in Kidney Transplantation: A State-of-the-Art Review.

BK virus maintains a latent infection that is ubiquitous in humans. It has a propensity for reactivation in the setting of a dysfunctional cellular immune response and is frequently encountered in kidney transplant recipients. Screening for the virus has been effective in preventing progression to nephropathy and graft loss. However, it can be a diagnostic and therapeutic challenge. In this in-depth state-of-the-art review, we will discuss the history of the virus, virology, epidemiology, cellular response, pathogenesis, methods of screening and diagnosis, evidence-based treatment strategies, and upcoming therapeutics, along with the issue of re-transplantation in patients.

Characterization of interstitial infiltrates in MPO and PR3 anti-neutrophil cytoplasmic antibody glomerulonephritis.

INTRODUCTION: It has been recognized that T cells have a pathogenic role in anti-neutrophil cytoplasmic antibody- (ANCA) associated vasculitis, in addition to being dominant cells in the interstitium in ANCA glomerulonephritis (GN). Given there are differences in renal outcomes based on ANCA type, we sought to characterize the interstitial infiltrate in ANCA GN to determine differences in relation to ANCA type and renal function. METHODS: Immunohistochemistry stains for CD3, CD4, CD20, C4d and FOXP3 were done in renal biopsies of patients with ANCA GN. Light microscopy was used to determine the percentage of cortical interstitium containing positive cells. Demographics, ANCA type and entry eGFR were recorded. The level of staining was compared between ANCA type and entry eGFR using Wilcoxon rank-sum test. RESULTS: Renal biopsies of 16 patients with MPO and 14 with PR3 ANCA GN were studied. CD3 cells were the predominant cells, with all biopsies staining positive for CD4 and FOXP3. C4d staining was negative in all biopsies, with no significant difference in staining between MPO and PR3 groups for any of the identified cell types. However, regardless of ANCA type, FOXP3 staining was significantly higher in patients with baseline GFR < 10 compared with GFR > 10 mL/min/1.73 m2(mean 7.54, SD 6.6 versus mean 2.67, SD 3.6; p = 0.04). CONCLUSION: These data confirm the role of T cells in ANCA GN and demonstrate no differences in interstitial T and B cell infiltrates between PR3 and MPO ANCA GN. Higher FOXP3 signal associates with lower renal function, suggesting a role for regulatory T cells. Further characterization of this T cell subset should be explored in future studies.