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 C 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 C in the basement membranes of lung alveoli.