α1-アンチトリプシン欠乏症に合併したChurg-Strauss症候群の1例

A Case of α1-antitrypsin-deficiency Complicated with Churg-Strauss Syndrome

要旨　α₁-アンチトリプシン(α₁-AT)欠乏症は肺気腫を高率に合併することで知られているが，本邦では極めて稀な疾患であり，わずか20数家系が報告されているにすぎない．われわれは，α₁-AT欠乏症の家系に発症したChurg-Strauss症候群(CSS)の1例を経験した．患者は67歳，女性．40歳より気道感染を繰り返し，50歳の時に肺炎で入院した際にα₁-AT欠乏症と診断された．2002年5月1日頃から咳嗽，発熱，両下肢の痛みが出現し，好酸球増多，肺野浸潤影，抗好中球細胞質ミエロペルオキシダーゼ抗体(MPO-ANCA)高値，アレルギー性鼻炎の既往からChurg-Strauss症候群と診断され，ステロイドとサイクロフォスファミドの併用療法で良好に経過した．α₁-ATはプロテアーゼのインヒビターとして働き，炎症を制御している．その欠乏は血管炎症候群のリスクとなる可能性があり，両疾患の関連性が示唆される興味深い1例である．

　Alpha₁-antitrypsin(α₁-AT)-deficiency is known to be associated with pulmonary emphysema. It is relatively rare in Japan and there have been only around 20 cases reported so far. Here, we describe an interesting case of Churg-Strauss syndrome(CSS) occurring in α₁-AT deficiency. The patient was a 67-year-old Japanese woman who had been repeatedly hospitalized due to pneumonia for more than 20 years. She was diagnosed as having α₁-AT deficiency with bronchiectasis in 1988, when she was admitted to our hospital because of a respiratory infection. Then, in May, 2002, she started to present cough, fever and bilateral leg pain and was diagnosed as having CSS on the basis of her past history of allergic rhinitis, pulmonary infiltration, eosinophilia and the presence of antineutrophil cytoplasmic antibody to myeloperoxidase(MPO-ANCA). She was successfully treated with oral steroids and intravenous cyclophosphamide therapy. α₁-AT is a major proteinase inhibitor and is thought to control inflammation in vivo. Alpha₁-AT deficiency might be involved in the pathogenesis of ANCA-associated vasculitis syndrome.