ABSTRACT
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 that have 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 was 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 and demonstrated a high frequency of APOL1 high-risk genotypes within this group, with no evidence of direct viral infection within the kidney.
Subject(s)
Acute Kidney Injury , COVID-19 , Apolipoprotein L1/genetics , Humans , Kidney , Retrospective Studies , SARS-CoV-2ABSTRACT
Coronavirus disease 19 (COVID-19), an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been associated with acute kidney injury, presumably due to acute tubular injury. However, this does not explain proteinuria, sometimes severe, and hematuria often observed. We present 2 African American patients with glomerulopathy demonstrated by kidney biopsy in the setting of acute kidney injury and COVID-19 infection. Kidney biopsy specimens showed a collapsing variant of focal segmental glomerulosclerosis in addition to acute tubular injury. Both patients were homozygous for apolipoprotein L1 (APOL1). COVID-19 infection likely caused the interferon surge as a second hit causing podocyte injury leading to collapsing focal segmental glomerulosclerosis. APOL1 testing should be strongly considered in African American patients with nephrotic-range proteinuria. More data from future kidney biopsies will further elucidate the pathology of kidney injury and glomerular involvement from COVID-19 infections.