[A case of PR3-ANCA positive granulomatosis with polyangiitis recurrent with acute kidney injury after 7 years remission].

A 62-year-old-Japanese man had a history of probable granulomatosis with polyangiitis (GPA) from 7 years previously, showing kidney and vasculitis symptoms with PR3-ANCA (864 EU) without renal biopsy. Remission with normalization of renal function and urinary findings was induced by corticosteroid therapy. Prednisolone (PSL) was tapered to 5 mg/day and maintained for 6.5 years with a low positive titer of PR3-ANCA. After 7 years of remission, he was referred to our hospital because of arthralgia, fever, general fatigue and appetite loss with apparent urinary abnormality, increased serum Cr (1.8 mg/dL) and C reactive protein (CRP : 30.1 mg/dL). On admission, he showed a high titer of PR3-ANCA (> 300 U/mL). Renal biopsy demonstrated the existence of the pauci-immune type of severe crescentic necrotizing glomerulonephritis, tubulo-interstitial damage and perivascular granuloma. He was diagnosed as relapse of GPA (kidney-localized type) without upper respiratory tract (E) and lung (L) symptoms. Accordingly, he received steroid pulse therapy leading to improvement of these symptoms and renal function. Oral PSL at the dosage of 40 mg/day was administered after steroid pulse therapy, and then tapered to 20 mg/day. Cyclophosphamide was added within 8 weeks. He was discharged 8 weeks after treatment with a decreased level of Cr (1.5 mg/dL) and PR3-ANCA (244 U/mL). After discharge, PSL was tapered to 10 mg/day during the course of stability resulting in a further improved level of Cr (1.2 mg/dL), PR3-ANCA 40 U/mL in the outpatient clinic. In Japan, PR3-ANCA-positive GPA has a lower incidence than MPO-ANCA-positive microscopic vasculitis. In GPA, the kidney-localized (K) type without upper respiratory tract (E, L) symptoms is rare. Histologically, not only necrotizing crescentic glomerulonephritis but also perivascular granuloma in the kidney are very rare and interesting.