6) 混合性結合組織病

MCTD ; Mixed connective tissue disease

混合性結合組織病(MCTD)は1972年米国のSharpらにより提唱された疾患概念で，SLE，SSc，PMの3つのうち，2つ以上の臨床所見が混在し，抗U1-RNP抗体が高値陽性を特徴とする疾患である．本邦では厚生労働省が特定疾患に指定しており，広くMCTDの概念は行き渡っている．MCTDの経過では手指・手の腫脹は長期にわたって持続することや肺高血圧症(PH)の合併率が他の膠原病に比較して有意に高いことが示されている．PHはMCTDの予後を規定する重要な合併症であり，MCTDの診断と同時にPHについても早期発見に努めることが重要である．PHの治療薬，治療法の進歩により予後の改善が期待されている．

Mixed connective tissue disease (MCTD) is a disease concept proposed by Sharp and his colleagues in 1972, combining more than 2 of 3 features of SLE, systemic sclerosis and polymyositis, together with the presence of a high titer of antibodies to U1-RNP.　In Japan, MCTD is designated a specific disease by the Ministry of Health, Labour and Welfare and the concept of MCTD is well known.　It is shown that swollen fingers and hands have continued during the long course of the disease, and pulmonary hypertension (PH) is significantly higher than in other collagen diseases in MCTD.　The worse prognosis in MCTD is attributable to PH, early diagnosis of MCTD and also PH associated with MCTD should be pursued.　Recent development of therapeutic agents and treatment is expected to improve disease prognosis.