Lupus nephritis associated with positive MPO-ANCA in a patient with underlying autoimmune hemolytic anemia

A 19-year-old female was admitted with general malaise and systemic edema. She had been diagnosed as having autoimmune hemolytic anemia (AIHA) eight years earlier and was successfully managed with oral prednisolone. During the current admission, she was diagnosed as having systemic lupus erythematosus (SLE) based on the presence of renal involvement, hematological abnormalities, and antinuclear and anti-double-stranded DNA antibodies, along with a recurrence of AIHA; her serology revealed a high myeloperoxydase-antineutrophil cytoplasmic antibody (MPO-ANCA) titer. She was treated with prednisolone (50 mg day⁻¹), but her renal function started to deteriorate. She responded to treatment with hemodialysis, plasmapheresis, and methylprednisolone pulse therapy; her MPO-ANCA titer and renal function improved. Treatment with intravenous cyclophosphamide gradually suppressed her AIHA and SLE activity. A renal biopsy revealed a diffuse proliferative lupus nephritis (class IV-G (A)) with necrotizing crescentic glomerulonephritis that was presumed to be associated with MPO-ANCA. The association of MPO-ANCA with SLE in this refractory case is discussed.