Multiple occurrences of membranous nephropathy complicated with anti-glomerular basement membrane antibody and anti-neutrophil cytoplasm antibody double-negative crescentic formation since the COVID-19 pandemic: A case series.

There has been an unusual increase in the incidence of anti-glomerular basement membrane disease, anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis, and double-positive cases since the coronavirus disease 2019 (COVID-19) pandemic. Rare cases have been consistently reported, including anti-glomerular basement membrane antibody and ANCA double-positive crescentic glomerulonephritis after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as well as coexistent membranous nephropathy and proteinase 3 ANCA-associated crescentic glomerulonephritis following vaccination. We described both anti-phospholipase A2 receptor (PLA2R) antibody-positive and -negative membranous nephropathy superimposed on anti-glomerular basement membrane disease. Upon and beyond these findings, we herein reported three cases of biopsy-confirmed membranous nephropathy concurrent with anti-glomerular basement membrane antibody and ANCA double-negative crescentic formation, which manifested as acute kidney injury clinically. In one case, repeated renal biopsies confirmed