A Japanese case of proteinase 3 antineutrophil cytoplasmic autoantibody-associated pauci-immune-type crescentic glomerulonephritis without valvular endocarditis

A 74-year-old male without recent medical treatment visited our hospital complaining of fever and lack of appetite. Upon examination severe azotemia, proteinuria, and urinary occult blood were noted, and the patient was admitted. Results of a blood test showed that his proteinase 3 antineutrophil cytoplasmic autoantibody (PR3-ANCA) level was high. A transthoracic echocardiogram indicated normal cardiac function and no valvular regurgitation or stenosis. Necrotizing glomerulonephritis accompanied by cellular crescentic bodies, but not granuloma, was noted on renal biopsy. An immunofluorescence study demonstrated no immunofluorescence staining in the glomerulus or in the tubulointerstitial or vascular compartments. No lesion was present in the lung or upper respiratory tract. The patient was diagnosed with PR3-ANCA-associated pauci-immune-type crescentic glomerulonephritis and treated with steroids. This treatment resulted in rapid normalization of C-reactive protein, and the PR3-ANCA level slowly decreased and converted to negative. The renal function, however, did not improve, and maintenance dialysis was introduced. No pulmonary or upper airway lesion has developed during 18?months of follow-up. PR3-ANCA-positive crescentic glomerulonephritis accompanied by valvular endocarditis has been described by several reports in Japan; however, this case was not complicated by valvular endocarditis. To our knowledge, this is the 4th case report describing PR3-ANCA-associated crescentic glomerulonephritis in Japan.