Complete Response in a Patient with New-Onset Lupus Nephritis following COVID-19 Vaccination

Introduction: Recent studies have suggested a potential association between the coronavirus disease 2019 (COVID-19) vaccination and the development or exacerbation of LN. Here, we present a case of a patient who was diagnosed with LN class IV after receiving the COVID-19 vaccine and achieved a complete response through immunosuppressive therapy. Case Description: A woman in her 50s presented with nephrotic syndrome, deteriorating kidney function 1 month after receiving a Pfizer-BioNTech COVID-19 vaccine. Her creatinine level was normal prior to vaccination, but she developed edema 1 week after receiving the vaccine. All serologic tests were negative, but the patient showed positive results for both anti-nuclear antibodies (ANA) and anti-double stranded (ds) DNA, as well as low complement C3 levels. An emergency kidney biopsy confirmed diffuse proliferative crescentic LN class IV. Induction therapy involved intravenous methylprednisolone and cyclophosphamide, followed by maintenance therapy with prednisolone and mycophenolate mofetil. At the 18-month follow-up, the patient achieved a complete response, experiencing full recovery of kidney function, improvement in proteinuria, and even seroconversion to negative for both ANA and anti-dsDNA. In the repeat biopsy conducted two years later, the activity index significantly decreased compared to the initial biopsy. However, persistent disease activity was evident, accompanied by a slight increase in the chronicity index. Discussion: Timely diagnosis and prompt immunosuppressive therapy are crucial for achieving favorable outcomes, even in severe cases of LN that occur after COVID-19 vaccination. Additionally, a repeat biopsy may contribute to assessing disease activity at the tissue level and predicting prognosis.