Successful Management of Lupus Nephritis with High Titers of Myeloperoxidase Anti-Neutrophil Cytoplasmic Antibodies Using Tacrolimus

A 63-year-old Japanese woman with a 30-year history of systemic lupus erythematosus developed macrohematuria and massive proteinuria after seroconversion of myeloperoxidase anti-neutrophil cytoplasmic antibodies (MPO-ANCA). A renal biopsy indicated focal proliferative lupus nephritis (class III A/C) with a fibrous crescent formation. Methylprednisolone pulse therapy (500 mg, 3 successive days) was administered because of progressive proteinuria. Steroid therapy did not suppress the progressive proteinuria; therefore, tacrolimus was added as an alternative immunosuppressive therapy, resulting in the improvement of proteinuria and renal impairment. This case report suggests that MPO-ANCA might play a pathogenic role in the exacerbation of immune-complex-type lupus nephritis.