RESUMO
Introduction: Primary membranous nephropathy (MN) is most commonly due to phospholipase A2 receptor antibodies (PLA2R Ab). It is unclear whether the COVID-19 vaccine can trigger flares of glomerular diseases such as primary MN. We present a patient with MN and metastatic breast cancer who developed nephrotic syndrome after receiving her second mRNA-1273 COVID-19 vaccine with positive PLA2R Ab by ELISA suggesting MN flare. Case Description: A 62 year old female with history of Stage IIIB T3N3M1 ER/PR positive HER-2 negative metastatic left breast invasive ductal carcinoma, hypertension, hyperlipidemia, and primary MN presented with bilateral leg edema, dyspnea, and proteinuria 2 weeks after COVID-19 vaccination. She had previous proteinuria of 7029 mg/24hr in August 2018 with PLA2R Ab 128 RU/mL in October 2018. She underwent modified radical mastectomy in September 2018 followed by adjuvant chemotherapy in November 2018, after which PLA2R Ab decreased to <2 RU/mL in February 2019 and urine protein/Cr ratio (UPCR) decreased to 1094 mg/g Cr in April 2019. She was diagnosed with metastatic breast cancer and started anastrazole transiently. She received mRNA-1273 COVID-19 vaccines in late January and February 2021. In March 2021, she presented with bilateral leg edema, dyspnea, and bilateral pleural effusions. Urinalysis had >1000 protein, 24hr urine protein 11.2 g, Cr 1.6 mg/dL, and PLA2R Ab 787 RU/mL. Renal biopsy showed immune complex-mediated glomerulopathy with positive PLA2R, consistent with primary MN stage II-III. Glomerular basement membrane deposits were strongly positive for IgG4. Electron microscopy showed numerous subepithelial and occasional intramembranous electron-dense immune-type deposits. She was treated with lisinopril and furosemide followed by rituximab in May 2021. Prior to rituximab PLA2R Ab was 342 RU/mL and UPCR was 8671 mg/g Cr. Discussion: There is insufficient data on the risk of flare after COVID-19 vaccine in glomerular diseases. There have been a few case reports of primary MN and minimal change disease after COVID-19 vaccine as well as MN after influenza vaccine. Our case of primary MN flare after COVID-19 vaccine adds support to a potential association between SARS-CoV-2 antigens and loss of tolerance to the PLA2R antigen. Close follow-up of patients with primary MN and other glomerular diseases after COVID-19 vaccination is warranted.