The clinical significance of receiving a kidney allograft from deceased donor with chronic histologic changes

C3 Glomerulopathy Recurs Early after Kidney Transplantation in Serial Biopsies Performed within the First 2 Years after Transplantation

Background

C3 glomerulopathy (C3G), which encompasses C3GN and dense deposit disease (DDD), results from dysregulation of the alternative complement pathway. Data on disease recurrence after kidney transplantation are limited, and details on histologic features of recurrent C3G are scarce. We aimed to evaluate C3G recurrence in the allograft, with a focus on histologic presentation and progression.

Methods

We retrospectively analyzed 18 patients with native kidney failure attributed to C3G (12 C3GN and six DDD), who received a kidney transplant from January 2016 to January 2023. Demographic, genetic, clinical, and histologic data were studied. The NanoString 770 genes PanCancer Immune Profiling Panel was used for transcriptomic analysis. Disease recurrence was the primary outcome.

Results

During a median (interquartile range) follow-up period of 37 (18–56) months, C3G recurrence occurred in 16 (89%) patients (11 with C3GN and five with DDD) at a median (interquartile range) of 33 (13–141) days after transplantation. Over a third (38%) of recurrent cases were detected in protocol biopsies, and only 31% of patients presented with >300 mg/g of proteinuria. Recurrence in index biopsies was mainly established through a combination of immunofluorescence and electron microscopy findings, while it showed only subtle histologic alterations and no characteristic transcriptomic signals. Over time, histologic chronicity indices increased, but all the allografts were functioning at the end of follow-up. Patients with recurrence of C3GN and DDD showed overlapping immunofluorescence and electron microscopy findings and had similar recurrence rate and time to recurrence.

Conclusions

Most of the patients with native kidney failure attributed to C3G developed disease recurrence very early after kidney transplantation, usually with minimal proteinuria, mild histologic alterations, and favorable short-term allograft survival. Immunofluorescence and electron microscopy played a crucial role in detecting early, subclinical recurrence of C3GN and DDD, which showed significant overlapping features.

The pathologic spectrum of adenovirus nephritis in the kidney allograft

Adenovirus nephritis (ADVN) is a rare and understudied complication of kidney transplantation. Unlike BK virus nephropathy (BKVN), our knowledge of clinicopathologic manifestations of ADVN remains rudimentary and essentially limited to case reports. To expand on this, we retrospectively studied 11 kidney transplant recipients with ADVN and compared their allograft biopsies to 33 kidney transplant recipients with BKVN using conventional microscopy and the 770 gene Nanostring Banff Human Organ Transplant Profiling Panel. Patients with ADVN had a median age of 44 years, were predominantly male, and developed ADVN at a median of 31 months post-transplantation. Eight patients presented with fever and ten had hematuria. The most common histologic manifestations included granulomas (82%), tubulocentric inflammation (73%), and tubular degenerative changes consistent with acute tubular necrosis (73%). During a median follow-up of 55 months after biopsy, three patients developed allograft failure from subsequent acute rejection. All seven patients with available follow-up PCR showed resolution of viremia at a median of 30 days after diagnosis. Compared to BKVN, ADVN demonstrated more granulomas and less tubulointerstitial scarring. On follow-up, patients with ADVN had more rapid clearance of viral DNA from plasma. Transcriptomic analyses showed that ADVN had increased expression of several pro-inflammatory transcriptomes, mainly related to innate immunity, was associated with increased expression of transcripts with inhibitory effects on inflammatory response and showed higher enrichment with neutrophils, which can cause aggressive but short-lasting damage. Thus, we demonstrate that, despite its association with aggressive neutrophil-rich inflammation, ADVN does not often lead to allograft failure. Hence, preventing subsequent acute rejection following resolution of ADVN may improve allograft survival.

Can Gene Expression Analysis in Zero-Time Biopsies Predict Kidney Transplant Rejection?

Zero-time biopsies are taken to determine the quality of the donor organ at the time of transplantation. Histological analyses alone have so far not been able to identify parameters that allow the prediction of subsequent rejection episodes or graft survival. This study investigated whether gene expression analyses of zero-time biopsies might support this prediction. Using a well-characterized cohort of 26 zero-time biopsies from renal transplant patients that include 4 living donor (LD) and 22 deceased donor (DD) biopsies that later developed no rejection (Ctrl, n = 7), delayed graft function (DGF, n = 4), cellular (T-cell mediated rejection; TCMR, n = 8), or antibody-mediated rejection (ABMR, n = 7), we analyzed gene expression profiles for different types of subsequent renal transplant complication. To this end, RNA was isolated from formalin-fixed, paraffin-embedded (FFPE) sections and gene expression profiles were quantified. Results were correlated with transplant data and B-cell, and plasma cell infiltration was assessed by immunofluorescence microscopy. Both principal component analysis and clustering analysis of gene expression data revealed marked separation between LDs and DDs. Differential expression analysis identified 185 significant differentially expressed genes (adjusted p < 0.05). The expression of 68% of these genes significantly correlated with cold ischemia time (CIT). Furthermore, immunoglobulins were differentially expressed in zero-time biopsies from transplants later developing rejection (TCMR + ABMR) compared to non-rejected (Ctrl + DGF) transplants. In addition, immunoglobulin expression did not correlate with CIT but was increased in transplants with previous acute renal failure (ARF). In conclusion, gene expression profiles in zero-time biopsies derived from LDs are markedly different from those of DDs. Pre-transplant ARF increased immunoglobulin expression, which might be involved in triggering later rejection events. However, these findings must be confirmed in larger cohorts and the role of early immunoglobulin upregulation in zero-biopsies needs further clarification.

Ratner L, Santoriello D, Barry Stokes M, Markowitz GS, Pereira MR, D’Agati VD, Batal I. Kidney allograft biopsy findings after COVID-19

COVID-19 has been associated with acute kidney injury and published reports of native kidney biopsies have reported diverse pathologies. Case series directed specifically to kidney allograft biopsy findings in the setting of COVID-19 are lacking. We evaluated 18 kidney transplant recipients who were infected with SARS-CoV-2 and underwent allograft biopsy. Patients had a median age of 55 years, six were female, and five were Black. Fifteen patients developed COVID-19 pneumonia, of which five required mechanical ventilation. Notably, five of 11 (45%) biopsies obtained within 1 month of positive SARS-CoV-2 PCR showed acute rejection (four with arteritis, three of which were not associated with reduced immunosuppression). The remaining six biopsies revealed podocytopathy (n = 2, collapsing glomerulopathy and lupus podocytopathy), acute tubular injury (n = 2), infarction (n = 1), and transplant glomerulopathy (n = 1). Biopsies performed >1 month after positive SARS-CoV-2 PCR revealed collapsing glomerulopathy (n = 1), acute tubular injury (n = 1), and nonspecific histologic findings (n = 5). No direct viral infection of the kidney allograft was detected by immunohistochemistry, in situ hybridization, or electron microscopy. On follow-up, two patients died and most patients showed persistent allograft dysfunction. In conclusion, we demonstrate diverse causes of kidney allograft dysfunction after COVID-19, the most common being acute rejection with arteritis.