Eculizumab in Combination with Immunosuppressant for the treatment of Autoimmune-Associated C3 Glomerulonephritis: A Case Report

A young female patient developed facial edema following fever, accompanied by nephrotic-range proteinuria, massive microscopic hematuria, and elevated serum creatinine. Additionally, she had anemia, severe hypocomplementemia, and a positive antinuclear antibody (ANA). Before referral to our center, she was diagnosed with "lupus nephritis Class IV" by renal biopsy at a local hospital. After re-evaluation, the diagnosis was revised to C3 glomerulonephritis (C3GN). Comprehensive complement testing showed positive serum C3 nephritic factor (C3NeF), anti-complement factor H antibody (FHAA), and anti-complement factor I antibody (FIAA), as well as abnormally elevated levels of Ba and sC5b-9. Following treatment with high-dose glucocorticoids, short-course eculizumab, and mycophenolate mofetil, her kidney injury improved rapidly. After 15 weeks of therapy, complete renal remission was achieved, with complement levels and antibodies returning to normal.