ANCA-associated vasculitis after COVID-19.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) are systemic autoimmune diseases that may lead to renal failure due to the infiltration of mononuclear cells and the destruction of small- and medium-sized blood vessels. It has been shown that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may trigger the presentation or exacerbation of autoimmune diseases. Crescentic glomerulonephritis (GN) has rarely been reported in patients with Coronavirus disease-2019 (COVID-19). We present rare two cases with AAV after a recent diagnosis of COVID-19. The first case was 26-year-old male patient, who was presented with acute kidney injury after COVID-19. Serum creatinine increased and active urine sediment was seen. Serological evaluation showed anti-myeloperoxidase antibody was at a level of 80.6 U/mL. Kidney biopsy showed necrotizing GN with cellular crescents. Methylprednisolone, cyclophosphamide and plasma exchange were administered. He was discharged with hemodialysis. Second case was a 36-year-old female who was hospitalized because of fever, cough and dyspnea. After she was diagnosed with COVID-19, she had total hearing loss, with cavitary lesions on bilateral lung parenchyma and an acute kidney injury. Serological evaluation showed an elevated anti-proteinase-3 with a level of 1:32. Kidney biopsy showed necrotizing GN with cellular crescents. Renal function improved after methylprednisolone and cyclophosphamide treatment. With a systematic review of the literature, we found four cases of new-onset AAV due to COVID-19. Herein, we discuss two cases and provide a literature review on cases of new-onset pauci-immune GN after COVID-19 infection.