8) 成人Still病

Adult onset Still's disease

成人Still病(AOSD)は全身の炎症性疾患であり，不明熱を呈する代表疾患の1つである．病因は不明で，自己免疫機序を示す証拠はないが，病態形成には炎症性サイトカインが深く関与している．治療には，一般に中等量のステロイドを使用するが，重症例にはステロイドパルス療法や免疫抑制薬，生物学的製剤も必要となる．特にマクロファージ活性化が著明となった血球貪食症候群(HPS)や播種性血管内凝固(DIC)などの合併は重篤で，注意を要する．予後は一般に良好であるが，再発や遷延化する例も少なくなく，ステロイドから完全に離脱できるのは，1/4～1/3に過ぎない．また，慢性関節炎型はしばしば手関節の強直を起こす．

Adult onset Still's disease (AOSD) is a systemic inflammatory disorder of unknown etiology, characterized by spiking fevers with an evanescent rash and arthritis.　Being a rare disease, AOSD is now known as a disease of unknown origin, giving rise to fever.　The etiology of AOSD is currently unknown.　Although no autoantibodies are seen in patients with AOSD, proinflammatory cytokines produced by activated macrophages may play critical roles in the pathophysiology of AOSD.　In general, intermediate or high-dose steroids can well control the disease.　For patients intolerant of steroids, immunosuppressive agents such as methotrexate (MTX) or cyclosporine A are needed.　In recent years, some biologics are also sometimes used, of which IL-6 blocking agent, tocilizumab seems to be the most promising.