ABSTRACT
Atypical anti-glomerular basement membrane (GBM) nephritis is a slowly progressive characterized by linear deposition of immunoglobulin (Ig) G in the GBM without circulating anti-GBM antibodies or lung involvement. There is no established therapy for this disease, and efficacy of the immunosuppressive treatment is questionable. A few cases of atypical anti-GBM nephritis have been reported after administration of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine. Classic anti-GBM disease has also been reported after the administration of the second dose of the SARS-CoV-2 vaccine. Herein, we present the case of a SARS-CoV-2 vaccine-induced atypical anti-GBM nephritis that developed after the first dose and was unresponsive to immunosuppressive therapy. A 57-year-old Japanese woman developed edema 11 days after the first dose of the SARS-CoV-2 mRNA vaccine. She developed nephrotic-range proteinuria and microscopic hematuria. Renal biopsy revealed endocapillary proliferative glomerulonephritis with linear IgG deposition. However, electron-dense deposits were not detected on electron microscopy. The patient tested negative for circulating anti-GBM antibodies and was diagnosed with atypical anti-GBM nephritis. Although steroids and mizoribine were administered, the patient's renal function deteriorated. In conclusion, atypical anti-GBM nephritis may have earlier onset than the classic anti-GBM disease. Given its uncertainty of effectiveness, immunosuppressive agents should be carefully used for SARS-CoV-2 mRNA vaccine-induced atypical anti-GBM nephritis.