AP-VAS 2012 case report: anti-glomerular basement membrane disease with high titer of myeloperoxidase anti-neutrophil cytoplasmic antibody-an autopsy case report.

It has been reported that patients who are positive for both myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) and anti-glomerular basement membrane (GBM) antibody have a poor prognosis. We present an autopsy case of anti-GBM disease with a high titer of MPO-ANCA. The patient was a 77-year-old woman with a medical history of idiopathic interstitial pneumonia. After being treated for bacterial pneumonia, she was referred to our hospital for evaluation of non-nephrotic range proteinuria, hematuria, and a course of rapidly progressive glomerulonephritis. Results of urinalysis were 2+ for protein and 3+ for blood, with many dysmorphic red blood cells observed in the urinary sediment. A sample of a 24-h urine collection contained 0.3 g protein. The serum creatinine concentration was 5.0 mg/dl on admission. The patient tested positive for MPO-ANCA at a titer of >640 EU and for anti-GBM antibody at a titer of 14 EU. Renal biopsy revealed glomerulonephritis with crescent formation, and immunofluorescence studies showed that the glomeruli had a generalized linear fluorescence and anti-immunoglobulin G (IgG) and C3 along the peripheral glomerular capillaries. She was diagnosed with anti-GBM disease. Treatment was started with intravenous prednisolone and oral cyclophosphamide, followed by plasma exchange. Despite improved renal function, she died of pulmonary hemorrhage. Autopsy revealed deposits of IgG and C3 in the basement membranes of lung alveoli.