Researchers have found that SARS-CoV-2 protein deposits contribute to an autoimmune disease in which the body attacks the tiny filtering units of the kidneys.
The SARS-CoV-2 virus responsible for the deadly Covid-19 pandemic is worsening kidney injuries with protein deposits, a study has found. Researchers from Capital Medical University and Chifeng University in China have found that SARS-CoV-2 protein deposits in the kidneys are contributing to the “onset and recurrence of membranous nephropathy (MN),” an autoimmune disease in which the body attacks the tiny filtering units (glomeruli) of the kidneys.
Effect of SARS-CoV-2 on renal function
The study included 38 patients with biopsy-proven MN who developed new-onset proteinuria (elevated protein in urine) after Covid, and 100 patients with primary MN diagnosed before the pandemic as controls. “Thirteen of the 38 patients tested positive for SARS-CoV-2 nucleocapsid protein. Compared with control patients, clinical manifestations were more severe in patients after Covid infection,” the team said in the paper published in Kidney International Reports.
Patients with positive SARS-CoV-2 protein levels “had a higher proportion of nephrotic syndrome, lower serum albumin level, and higher severity of renal interstitial fibrosis than patients with negative SARS-CoV-2 protein levels.” “Our study suggests that SARS-CoV-2 infection may contribute to the deposition of viral protein beneath epithelial cells and lead to podocyte (kidney cell) injury,” the researchers said.
MN is the most common pathologic type of adult nephrotic syndrome, a kidney disorder that causes the body to excrete too much protein in the urine. It is characterized by the deposition of immune complexes beneath the glomerular epithelial cells, including specific antigens, IgG, and complement membrane attack complexes (MAC). Approximately 70 percent of MN are considered primary, while the remaining 30 percent are secondary to various etiologies, including infections such as hepatitis virus as one of the important secondary causes.
While previous studies showed that SARS-CoV-2 was primarily found in the renal tubular epithelial cells of COVID patients with kidney injury, the new study, for the first time, observed deposits of SARS-CoV-2 nucleocapsid protein along the glomerular basement membrane.
However, the researchers noted that “the relationship between SARS-CoV-2 protein deposition and MN pathogenesis remains unclear,” and called for further research into the matter.
(IANS)
