IgG4関連ミクリッツ病とシェーグレン症候群

IgG4-related Mikulicz's disease and Sjögren's syndrome

ミクリッツ病もシェーグレン症候群も19世紀後半より提唱された疾患概念であり，前者は対称性の涙腺・唾液腺腫脹をきたす病態で，一方，後者は自己免疫異常で乾燥性角結膜炎を呈する．ミクリッツ病は独立した疾患単位ではなく，シェーグレン症候群の一表現型であると考えられてきたが，本邦では両疾患の差異が注目され続けていた．2004年Yamamotoらがミクリッツ病はIgG4関連疾患であることを報告した．多施設共同研究の結果，IgG4関連ミクリッツ病はシェーグレン症候群に比べ，アレルギー性疾患合併が多く，抗SS-A/SS-B抗体陰性，リウマトイド因子(RF)や抗核抗体陽性率も1/4程度，血清IgG4，IgG2，IgEが高く，病理組織でIgG4陽性形質細胞浸潤著明で，ステロイド治療著効などの特徴を報告した．19世紀末より続いた両疾患の異同に関する議論について，ようやく決着が得られた．

Both Mikulicz's disease (MD) and Sjögren's syndrome (SS) have been proposed by late 19^th century.　MD is a condition that consists bilateral symmetrical swelling of lacrimal and salivary glands.　SS is an autoimmune disorder that is characterized by keratoconjunctivitis Sicca.　Although Morgan and Castleman concluded that MD was not a distinct clinical and pathological disease entity but merely one manifestation of a more generalized symptom complex known as SS in 1953, MD has been paid attention in Japan.　Since the first reported hyper-IgG4 gammaglobulinemia in sclerosing pancreatitis in 2001, various systemic conditions, including MD, correlating with IgG4 have been described.　We started a retrospective clinical study of IgG4-related disease including MD, and we concluded that IgG4-related MD and SS are significantly different conditions, with distant clinical and pathological characteristics, despite similarities in involved organs.