Improvement of rapidly progressive lupus nephritis associated MPO-ANCA with tacrolimus.

A 43-year-old Japanese woman with systemic lupus erythematosus (SLE) developed rapidly progressive renal failure and nephritic syndrome with a high titer of myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA). Methylprednisolone pulse therapy did not suppress the progression of renal failure. Intravenous cyclophosphamide pulse therapy and administration of azathioprine was abandoned due to adverse effects. Tacrolimus was employed as an alternative immunosuppressive therapy and was well tolerated, effectively preventing renal failure. Oral prednisolone dosage was successfully tapered without recurrence, along with decreasing titer of MPO-ANCA. Renal biopsy showed diffuse proliferative lupus nephritis (International Society of Nephrology/Renal Pathology Society class IV-G A/C) with crescent formation. These findings indicate that in addition to lupus nephritis, which usually results from deposition of circulating or locally formed immune complexes, MPO-ANCA may be involved in the pathogenesis of crescentic glomerulonephritis. Furthermore, we propose that tacrolimus is an effective immunosuppressant for MPO-ANCA-related renal crisis in diffuse proliferative lupus nephritis.