Mixed Connective Tissue Disease Developing into MPO-ANCA-positive Polyangiitis

Abstract

Renal involvement of mixed connective tissue disease (MCTD) shows systemic lupus erythematosus (SLE)-like immune complex glomerulonephritis. The prognosis of this condition is generally good. We report the case of an elderly female patient with MCTD who developed autoimmune pleurisy and rapidly progressive glomerulonephritis. Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) was positive with a titer of 59.0 EU. Anti-DNA antibody and complement levels were normal. Renal biopsy revealed crescentic glomerulonephritis and mild mesangial proliferation. However, immunofluorescence examination revealed immune-complex glomerulonephritis. These findings suggest that the renal involvement of MCTD developed concurrently with MPO-ANCA-related glomerulonephritis.

Sustained Remission of Antineutrophil Cytoplasmic Antibody-Mediated Glomerulonephritis and Nephrotic Syndrome in Mixed Connective Tissue Disease

“…These patients exhibited various patterns of other autoantibodies. Serum complement levels, not reported in two patients [9, 10], were depressed in three [11, 13] (this report) and normal in the remaining three patients [8, 12, 14]. …”

“…Renal histology was not available in two patients [11, 14]. Among the remaining six patients, one had atherosclerosis of the renal arteries but no glomerulonephritis [9] and the other five patients had pauci-immune glomerulonephritis [8, 10, 12, 13] (this report). Vasculitis treatment (cyclophosphamide and methylprednisolone) was used for patients with pauci-immune glomerulonephritis, while the patient with atherosclerosis received lipid-lowering treatment.…”

“…Presences of small amounts of immunoglobulin in the mesangium and immune complex deposition on the electron microscopic picture were also documented in another MCTD patient diagnosed with pauci-immune glomerulonephritis [13]. The concept of “dual glomerulopathy” is based on the observation of histological features of pauci-immune glomerulonephritis combined with immune complex deposition the magnitude of which cannot explain the extent of the renal histological damage [15].…”

Successful Immunosuppressive Treatment of Mixed Connective Tissue Disease Complicated by Microscopic Polyangiitis

“…However, alveolar hemorrhage is an extremely rare complication and may cause a fatal outcome (Germain and Davidman 1984;Horiki et al 1998). Myeloperoxidase-specific anti-neutrophil cytoplasmic antibody (MPO-ANCA) positive polyangiitis (microscopic polyangiitis, MPA) is a systemic autoimmune disorder, which is characterized by the inflammation of small vessels (arterioles, capillaries, and venules) mainly affecting the lung and kidney (Murakami et al 2011). Complication of MPA in patients with MCTD is rare.…”

“…Complication of MPA in patients with MCTD is rare. So far, only nine MCTD cases accompanied by MPO-ANCApositive MPA have been described (Inada et al 1999;Makita et al 2000;Hernández-Molina et al 2006;Kitaura et al 2006;Hong et al 2010;Murakami et al 2011;Konstantinov et al 2013;Murakami et al 2013;Sun et al 2014). Here we report a rare case of MCTD complicated by MPA with alveolar hemorrhage, responding well to immunosuppressive treatment.…”