MPO-ANCA-positive Microscopic Polyangiitis Following COVID-19 Infection.

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a systemic disease that causes vasculitis in various organs. Although the cause of the onset is unknown, infection has been reported to be a causative factor. The subsequent cytokine storm triggered by the immune response against SARS-CoV-2 infection has been reported to lead to symptoms being more severe. We herein report our experience with the onset of AAV following COVID-19 infection. We also report the course of anti-SARS-CoV-2 serum antibody titers following induction therapy, which suggests that vaccination and education concerning standard precautions are necessary in patients who require immunosuppressive therapy, even after COVID-19 infection.