Role of time from transplantation to biopsy in histologic ABMR: A single center report.

BACKGROUND: Allograft biopsies with lesions of Antibody-Mediated Rejection (ABMR) with Microvascular Inflammation (MVI) have shown heterogeneous etiologies and outcomes. METHODS: To examine factors associated with outcomes in biopsies that meet histologic ABMR criteria, we retrospectively evaluated for-cause biopsies at our center between 2011 and 2017. We included biopsies that met the diagnosis of ABMR by histology, along with simultaneous evaluation for anti-Human Leukocyte Antigen (HLA) donor-specific antibodies (DSA). We evaluated death-censored graft loss (DCGL) and used a principal component analysis (PCA) approach to identify key predictors of outcomes. RESULTS: Out of the histologic ABMR cohort (n = 118), 70 were DSA-positive ABMR, while 48 had no DSA. DSA(+)ABMR were younger and more often female recipients. DSA(+)ABMR occurred significantly later post-transplant than DSA(-)ABMR suggesting time-dependence. DSA(+)ABMR had higher inflammatory scores (i,t), chronicity scores (ci, ct) and tended to have higher MVI scores. Immunodominance of DQ-DSA in DSA(+)ABMR was associated with higher i+t scores. Clinical/histologic factors significantly associated with DCGL after biopsy were inputted into the PCA. Principal component-1 (PC-1), which contributed 34.8% of the variance, significantly correlated with time from transplantation to biopsy, ci/ct scores and DCGL. In the PCA analyses, i, t scores, DQ-DSA, and creatinine at biopsy retained significant correlations with GL-associated PCs. CONCLUSIONS: Time from transplantation to biopsy plays a major role in the prognosis of biopsies with histologic ABMR and MVI, likely due to ongoing chronic allograft injury over time.

Chronic transplant glomerulopathy: New insights into pathogenesis.

There have been recent significant advances in short-term outcomes in renal transplantation, however, long-term allograft survival remains a challenge. With reported incidences as high of 74.5% of chronic graft loss in patients with biopsies showing transplant glomerulopathy (TG), this syndrome represents an important factor for chronic allograft complications. In this review we show an overview of the novel mechanistic insights into pathogenesis of TG, as well as a brief description of the pathology, diagnosis and newer prognostic indices within TG diagnosis. These data raise intriguing roles for cell-mediated immunity and podocyte stress in TG as well as reinforce previous associations of TG with ABMR. We also delve into management strategies for TG and report the paucity of existing clinical trial data for this prevalent condition in renal transplants.

COVID-19 and the Kidney: A Worrisome Scenario of Acute and Chronic Consequences.

Acute kidney injury (AKI) is a common finding in patients with coronavirus disease 2019 (COVID-19) and has been associated with higher rates of death when compared to COVID-19 patients without kidney injury. Whereas the definitive pathogenesis of COVID-19-related AKI (CoV-AKI) is not clear, histopathologic evidence seems to point at multiple etiologies for the disease, including indirect and direct viral kidney injury. The high incidence of CoV-AKI, along with the aggressive clinical presentation of this entity, have increased the demands for kidney replacement therapies, rapidly overwhelming the supplies of healthcare systems even in major tertiary care centers. As a result, nephrologists have come up with alternatives to maximize the efficiency of treatments and have developed non-conventional therapeutic alternatives such as the implementation of acute peritoneal dialysis for critically ill patients. The long-term implications of CoV-AKI are yet unknown, though early studies suggest that around one third of the patients who survive will remain dependent on kidney replacement therapy. Nephrologists and healthcare workers need to be familiar with the clinical presentation and therapeutic challenges of CoV-AKI in order to develop strategies to mitigate the burden of the disease for patients, and for services providing kidney replacement therapies.

Urine Microscopy for Internal Medicine Residents: A Needs Assessment and Implementation of Virtual Teaching Sessions.

Background: Although urine microscopy is an important step in the initial evaluation of a patient with kidney disease, internal medicine residents have minimal exposure to this technique during their training. The goal of this study was to understand knowledge of and attitudes toward urine microscopy among internal medicine residents and to implement virtual urine microscopy teaching sessions. Methods: A voluntary, anonymous, online survey was sent to all of the categorical internal medicine residents (n=131) training at the Icahn School of Medicine at Mount Sinai (ISMMS). The survey included 13 questions to assess attitudes toward, experience with, and clinical interpretation of urine microscopy specimens. In response to the survey results, we implemented virtual urine microscopy teaching sessions using video conferencing software that incorporated real-time urine sediment analysis with nephrology fellows and attending nephrologists. Results: The survey response rate was 45% (59 of 131). Forty-seven percent (28 of 59) of respondents reported performing urine microscopy at least once during their training, and 75% (44 of 59) of respondents did not feel comfortable performing urine microscopy. The majority of residents (92%; 54 of 59) reported they felt urine microscopy was very helpful or somewhat helpful in the evaluation of patients with AKI. Overall, 41% of responses to clinical interpretation questions were considered correct. Following survey completion, virtual urine microscopy sessions were held monthly and well received by the participants. Conclusions: Our study found that internal medicine residents perceive urine microscopy as a helpful diagnostic tool, although lack the skills to perform and interpret urine microscopy sediments. Virtual educational sessions using video conferencing software are a technically feasible approach to teaching urine microscopy to internal medicine residents. Future studies include a study of the effect of these sessions on learning of urine microscopy. Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/K360/2021_01_28_KID0006282020.mp3.

Molecular Analysis of the Kidney From a Patient With COVID-19-Associated Collapsing Glomerulopathy.

Recent case reports suggest that coronavirus disease 2019 (COVID-19) is associated with collapsing glomerulopathy in African Americans with apolipoprotein L1 gene (APOL1) risk alleles; however, it is unclear whether disease pathogenesis is similar to HIV-associated nephropathy. RNA sequencing analysis of a kidney biopsy specimen from a patient with COVID-19-associated collapsing glomerulopathy and APOL1 risk alleles (G1/G1) revealed similar levels of APOL1 and angiotensin-converting enzyme 2 (ACE2) messenger RNA transcripts as compared with 12 control kidney samples downloaded from the GTEx (Genotype-Tissue Expression) Portal. Whole-genome sequencing of the COVID-19-associated collapsing glomerulopathy kidney sample identified 4 indel gene variants, 3 of which are of unknown significance with respect to chronic kidney disease and/or focal segmental glomerulosclerosis. Molecular profiling of the kidney demonstrated activation of COVID-19-associated cell injury pathways such as inflammation and coagulation. Evidence for direct severe acute respiratory syndrome coronavirus 2 infection of kidney cells was lacking, which is consistent with the findings of several recent studies. Interestingly, immunostaining of kidney biopsy sections revealed increased expression of phospho-STAT3 (signal transducer and activator of transcription 3) in both COVID-19-associated collapsing glomerulopathy and HIV-associated nephropathy as compared with control kidney tissue. Importantly, interleukin 6-induced activation of STAT3 may be a targetable mechanism driving COVID-19-associated acute kidney injury.