IgG4関連疾患の呼吸器病変

IgG4-related respiratory disease

高IgG4血症と諸臓器へのIgG4陽性形質細胞の浸潤を特徴とするIgG4関連疾患は，時間的・空間的に全身の臓器に多様な病変をきたす疾患である．その呼吸器病変の多くは，無症状で全身精査中に指摘されている．しかし，画像上は結節影，浸潤影，間質性陰影，胸水など多彩な陰影を認め，病変部位へのIgG4陽性形質細胞の程度も様々である．多臓器病変が同時に発症する場合の診断は，それほど困難ではないが，呼吸器単独病変での診断は容易ではない．今後は症例を集積して，その臨床症状や検査所見の特徴などを解析し，正確な診断と治療法を確立する必要がある．

Immunoglobulin G4 (IgG4)-related disease is a new concept concerning multi-organ disease, which involves respiratory systems.　Clinically, the respiratory disease occurs predominantly in elderly men.　They are usually asymptomatic, but some cases present bronchial asthma-like symptoms.　Chest CT shows various findings, such as thickening of broncho-vascular bundle with or without infiltration, interlobular thickening, tumor-like lesions, pleural abnormalities, and lymphadenopathy.　In laboratory data, the patients present high levels of serum IgG, IgG4 and IgE.　Pathologically, abundant plasma cell infiltration has been observed in various inflamed areas.　The diagnostic consensus of IgG4-related respiratory disease has not been established yet.　A large scale prospective study is required to clarify the feature and treatment of IgG4-related respiratory disease.