Tohoku J. Exp. Med., 2016 June, 239(2)

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

SHUZO SATO,¹ MAKIKO YASHIRO,¹ NAOKI MATSUOKA,¹ MANABU UEMATSU,² TOMOYUKI ASANO,¹ HIROKO KOBAYASHI,¹ HIROSHI WATANABE¹ and HIROMASA OHIRA¹

¹Department of Gastroenterology and Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Fukushima, Japan
²Department of Pulmonary Medicine, Fukushima Medical University School of Medicine, Fukushima, Fukushima, Japan

Mixed connective tissue disease (MCTD) is characterized by a combination of clinical features of systemic lupus erythematosus, systemic sclerosis, and polymyositis with elevated antibodies to U1 small nuclear ribonucleoprotein (U1-RNP). MCTD is often accompanied by interstitial lung disease as pulmonary involvement. On the other hand, microscopic polyangiitis (MPA) is a systemic autoimmune disease characterized by the inflammation of small vessels (arterioles, capillaries, and venules) mainly affecting the lung and kidney. MPA is associated with elevated serum anti-neutrophil cytoplasmic antibody (ANCA). Complication of MPA in patients with MCTD is rare. So far, only nine case reports of MCTD complicated by MPA with serum myeloperoxidase-specific ANCA (MPO-ANCA) are available. Here, we describe a 64-year-old male suffering from MCTD with MPA. The patient developed interstitial pneumonia with alveolar hemorrhage accompanied by myositis, scleroderma, and elevated anti-U1-RNP antibody and MPO-ANCA levels with substantial systemic inflammation. Strong immunosuppressive therapy (corticosteroid, intravenous immunoglobulin, and cyclosporine A) ameliorated the myositis, interstitial lung disease, and inflammation, with the decrease of MPO-ANCA levels, despite that severe lung complications are often associated with poor outcomes. In conclusion, MCTD may be accompanied by MPA with alveolar hemorrhage. Severe lung complications may indicate a poor outcome, and therefore prompt immunosuppressive treatment should be performed in such patients.

keywords —— alveolar hemorrhage; interstitial pneumonia; microscopic polyangiitis; mixed connective tissue disease; myeloperoxidase-specific anti-neutrophil cytoplasmic antibody

© 2016 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2016, 239, 111-116

Correspondence: Shuzo Sato, Department of Gastroenterology and Rheumatology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, Fukushima 960-1295, Japan.

e-mail: shuzo@fmu.ac.jp