[Two patients with pulmonary hemorrhage associated with myeloperoxidase-antineutrophil cytoplasmic antibody]

We encountered two patients with pulmonary hemorrhage who had high levels of myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA). Patient 1 was a 69-year-old woman. Both were admitted to our hospital complaining of hemoptysis. Microscopic hematuria was detected in patient 1, and proteinuria and renal insufficiency were detected in patient 2. Chest X-ray films showed bilateral patchy infiltrates in patient 1, and right middle-lower infiltrates in patient 2. In both patients the levels of MPO-ANCA were high and the results of tests for anti-basement membrane antibodies were negative. These patients were suspected to have pulmonary-renal vasculitic syndrome with a high level of MPO-ANCA. In patient 1, because the level of MPO-ANCA decreased after treatment with steroid therapy, we believe that measuring the level of MPO-ANCA was useful in the management of the disease. Rapidly progressive glomerulonephritis developed in patient 2, and was exacerbated despite hemodialysis, steroid therapy, and plasma exchange therapy. Use of the term microscopic polyangiitis (MPA) was first proposed by yhe Chapel Hill Consensus Conference in 1993. MPA, which was formerly called microscopic polyarteritis nodosa, connotes pauci-immune necrotizing vasculitis affecting arterioles, venules, or capillaries, and this condition is strongly associated with ANCA. Patients with pulmonary-renal vasculitic syndrome who have MPO-ANCA may be given a diagnosis of MPA. Therefore, we diagnosed MPA in these two patients. Testing for ANCA may be useful in patients with pulmonary hemorrhage and renal involvement.