Kidney failure is common in patients with Coronavirus Disease-19 (COVID-19) resulting in increased morbidity and mortality. In an international collaboration, 284 kidney biopsies were evaluated to improve understanding of kidney disease in COVID-19. Diagnoses were compared to five years of 63,575 native biopsies prior to the pandemic and 13,955 allograft biopsies to identify diseases increased in patients with COVID-19. Genotyping for APOL1 G1 and G2 alleles was performed in 107 African American and Hispanic patients. Immunohistochemistry for SARS-CoV-2 was utilized to assess direct viral infection in 273 cases along with clinical information at the time of biopsy. The leading indication for native biopsy was acute kidney injury (45.4%), followed by proteinuria with or without concurrent acute kidney injury (42.6%). There were more African American patients (44.6%) than patients of other ethnicities. The most common diagnosis in native biopsies was collapsing glomerulopathy (25.8%) which associated with high-risk APOL1 genotypes in 91.7% of cases. Compared to the five-year biopsy database, the frequency of myoglobin cast nephropathy and proliferative glomerulonephritis with monoclonal IgG deposits was also increased in patients with COVID-19 (3.3% and 1.7%, respectively), while there was a reduced frequency of chronic conditions (including diabetes mellitus, IgA nephropathy, and arterionephrosclerosis) as the primary diagnosis. In transplants, the leading indication was acute kidney injury (86.4%), for which rejection was the predominant diagnosis (61.4%). Direct SARS-CoV-2 viral infection was not identified. Thus, our multi-center large case series identified kidney diseases that disproportionately affect patients with COVID-19, demonstrated a high frequency of APOL1 high-risk genotypes within this group, with no evidence of direct viral infection within the kidney.

Collapsing glomerulopathy is an aggressive form of focal segmental glomerulosclerosis with diverse causes. The presence of the apolipoprotein L1 ( APOL1 ) high-risk genotype is a major risk factor for collapsing glomerulopathy in African Americans. Coronavirus disease 2019 (COVID-19) is an emerging pandemic with predominant respiratory manifestations. However, kidney involvement is being frequently noted and is associated with higher mortality. Currently, kidney pathology data for COVID-19 are scant and mostly come from postmortem findings. We report 2 African American patients who developed acute kidney injury and proteinuria in temporal association with COVID-19 infection. Kidney biopsy specimens showed collapsing glomerulopathy, endothelial tubuloreticular inclusions, and acute tubular injury, without evidence by electron microscopy or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in situ hybridization of viral infection of kidney cells. Both patients had the APOL1 high-risk genotype. We propose that collapsing glomerulopathy represents a novel manifestation of COVID-19 infection, especially in people of African descent with APOL1 risk alleles.

BackgroundAcute kidney injury (AKI) is a complication of coronavirus disease 2019 (COVID-19) that is associated with high mortality. Despite documented kidney tropism of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there are no consistent reports of viral detection in urine or correlation with AKI or COVID-19 severity. Here we hypothesize that quantification of SARS-CoV-2 viral load in urine sediment from COVID-19 patients correlates with occurrence of AKI and mortality. MethodsSARS-CoV-2 viral load in urine sediments (U-viral load) was quantified by qRT-PCR in 52 patients with PCR-confirmed COVID-19 diagnosis, hospitalized between March 15th and June 8th, 2020. Immunolabeling of SARS-CoV-2 proteins Spike and Nucleocapsid was performed in two COVID-19 kidney biopsies and urine sediments. Viral infectivity assays were performed from 32 urine sediments. ResultsTwenty COVID-19 patients (39%) had detectable SARS-CoV-2 U-viral load, of which 17 (85%) developed AKI with an average U-viral load 4-times higher than non-AKI COVID-19 patients. U-viral load was highest (7.7-fold) within two weeks after AKI diagnosis. A higher U-viral load correlated with mortality but not with albuminuria or AKI stage. SARS-CoV-2 proteins partially colocalized with the viral receptor ACE2 in kidney biopsies in tubules and parietal cells, and in urine sediment cells. Infective SARS-CoV-2 was not detected in urine sediments. ConclusionOur results further support SARS-CoV-2 kidney tropism. A higher SARS-CoV-2 viral load in urine sediments from COVID-19 patients correlated with increased incidence of AKI and mortality. Urinary viral detection could inform medical care of COVID-19 patients with kidney injury to improve prognosis.