A 75-year-old man presented with MPO-ANCA-positive rapidly progressive glomerulonephritis after COVID-19 vaccination during the treatment of plaque psoriasis vulgaris with bimekizumab. Bimekizumab, an anti-IL17 monoclonal antibody, was regularly administered to control the activity of plaque psoriasis. After receiving the sixth COVID-19 vaccine, his kidney function rapidly declined over the course of weeks. Urinalysis showed microscopic hematuria and proteinuria with deformed red blood cells and granular cast. The immunology test was positive for MPO-ANCA. The patient was clinically diagnosed with MPO-ANCA-associated glomerulonephritis. As the patient lost his appetite and developed lower extremity edema with low eGFR (< 15 ml/min/1.73m2) on admission day, hemodialysis induction was initiated along with methylprednisolone pulse, followed by oral prednisolone. The kidney function and urine volume were improved in response to immunosuppressive therapy, and withdrawal from hemodialysis was considered. However, the patient developed a catheter infection due to methicillin-sensitive Staphylococcus aureus 2 weeks after the initial prednisolone treatment, causing a decline in kidney function. Antibiotics treatment for the catheter infection was effective, but kidney function remained low, resulting in dependence on regular hemodialysis. COVID-19 vaccination provides significant improvement in overall prognosis; however, there have been reports of kidney function decline and exacerbation of hematuria in patients with IgA nephropathy following vaccination. The incidence of MPO-ANCA-associated glomerulonephritis after COVID-19 vaccination was rare. Data accumulation is warranted to understand the risk factors for secondary MPO-ANCA glomerulonephritis after COVID-19 vaccination. Regular monitoring of urinalysis and kidney function after COVID-19 vaccination is recommended in patients with psoriasis vulgaris treated with IL17 monoclonal antibodies.
