Human Kidney is a Target for Novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection

Abstract

BACKGROUND The coronavirus disease 2019 (COVID-19) is a newly emerged infection from the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Apart from the respiratory system, it is unclear whether SARS-CoV-2 can also directly infect other tissues such as the kidney or induce acute renal failure. METHODS We conducted a retrospective analysis of estimated glomerular filtration rate (eGFR), plasma creatinine, and urea concentrations along with other clinical parameters from 85 patients with laboratory-confirmed COVID-19 admitted to a hospital in Wuhan from January 17, 2020 to March 3, 2020. Kidney tissues from six other patients with postmortem examinations were analyzed by Hematoxylin and Eosin (H&E) and in situ expression of viral nucleocaspid protein (NP) antigen was detected by immunohistochemistry. RESULTS Among these 85 COVID-19 cases, 27.06% (23/85) patients exhibited acute renal failure (ARF), and elder patients (≥ 60 years old) are easier to develop ARF (65.22% vs 24.19%, p< 0.001). Comorbidities of disorders like hypertension and heart failure were more common in patients who developed ARF (69.57% vs 11.29%, p< 0.001). Dynamic observation of eGFR revealed that perished cases have a rapid decrease of eGFR but quickly boosting plasma creatinine and urea. On the other hand, enhancement of eGFR and persistence low level of plasma creatinine and urea was observed in recovery patients following diuretic treatment. H&E staining demonstrated kidney tissues from 6 cases of postmortems have severe acute tubular necrosis but no evidence of glomerular pathology or tubulointerstitial lymphocyte infiltration. Immunohistochemistry showed that SARS-CoV-2 NP antigen was accumulated in kidney tubules. CONCLUSIONS The development of ARF during the course of disease is an important negative prognostic indicator for survival with COVID-19. SARS-CoV-2 virus directly infects human kidney tubules by thus induces acute tubular damage, ARF and probably also lead to urine transmission.