Methods:
This single center study included 49 cases of onset or aggravation of kidney injury associated with COVID-19 infection between December 2022 and March 2023 in Nephrology Institute of the Second Xiangya Hospital ofCentral South University. 38 of them performed kidney biopsy.Inclusion criteria included cases with a confirmed COVID-19 infection by RNA PCR or antigen detection within one week before or after kidney injury. Patients were divided into 2 groups: Group A for patients with onset of kidney injury after SARS CoV-2 infection; Group B for patients with pre-existing kidney disease who experienced aggravation of renal insufficiency after SARS-CoV-2 infection.
Kidney biopsy sections were stained with hematoxylin and eosin(H&E), Periodic acid-Schiff(PAS),Masson-Trichrome, Periodic-acid silver methenamine (PASM), and Congo Red and examined by light microscopy. Immunofluorescence(IF) staining was performed for IgG, IgA, IgM, C3, C1q, Kappa light chain and Lambda light chain.All cases were diagnosed by nephropathologist.