A 46-year-old woman has had worsening malaise for the past 36 hours. Her urine output is markedly diminished, and it has a cloudy brown appearance. On examination, she has periorbital edema. Laboratory findings include serum creatinine of 2.8 mg/dL and urea nitrogen of 30 mg/dL. A renal biopsy is performed and on microscopic examination shows focal necrosis in glomeruli with glomerular basement membrane breaks and crescent formation. No immune deposits are identified with immunofluorescence. Which of the following autoantibodies is most likely detectable in her serum?

This is pauci-immune crescentic glomerulonephritis. The lack of immune deposits excludes anti-glomerular basement membrane disease (Goodpasture syndrome). Cases can be idiopathic, associated with ANCAs, and limited to the kidney. Rapidly progressive GN often has an abrupt onset with nephritis marked by oliguria. The Anti-DNA topoisomerase antibody is seen with scleroderma, which mainly affects the vasculature. The antinuclear antibody is present with many autoimmune diseases, such as SLE, with immune complex deposition in glomeruli. Anti-HBs may occur in some cases of secondary membranous nephropathy.