Nucleocapsid protein accumulates in renal tubular epithelium of a post-COVID-19 patient

In this study, we investigated whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral proteins and virus particles can be detected (i) in post-mortem kidney of fatal coronavirus disease 2019 (COVID-19) patients and (ii) in renal biopsy of patients sufferingfrom kidney failure months after combating a SARS-CoV-2 infection. Using fluorescencemicroscopy, antibodies against viral proteins [nucleocapsid, membrane (M), non-structural proteins (nsp) 3, 4, and 13] and double-stranded RNA (dsRNA) were validated on SARS-CoV-2-infected Vero cells. dsRNA was detected in lipid-filledelectron-lucent (white) compartments in SARS-CoV-2-producing cells. In the kidney of a patient with acute kidney failure, accumulation of SARS-CoV-2 nucleocapsid N protein was detected in tubular epithelium. In contrast, none of the other viral proteins (M, nsp3, 4, 13) nor dsRNA was detected in these regions, suggesting that no viral replication takes place in the kidney of these patients. High-resolution immunoelectron microscopy demonstrated N protein accumulation in Golgi-like structures but absence of intracellular virus particles. The presence of the N protein in Golgi-like structures in kidney of patients suggests that this protein may have an unforeseen role in post-COVID-19 renal complications.