16) 自己免疫性水疱症

Autoimmune bullous diseases

自己免疫性水疱症は，表皮細胞間接着にかかわるデスモグレインに対する自己抗体により表皮内に水疱を形成する天疱瘡群，表皮と真皮の接着に関与する分子に対する自己抗体が表皮下に水疱を形成する類天疱瘡群に大別される．本稿では，それぞれの自己免疫性水疱症における自己抗体の標的抗原および病態，診断に必要な検査および血清学的解析，臨床の現場における自己抗体検査の現状と将来の展望について解説する．特に天疱瘡と水疱性類天疱瘡におけるELISA法は，診断だけでなく治療効果判定にも有用であり，今後その重要性は高まると考えられる．

Autoimmune bullous diseases are divided into two groups by the site of blister formation, which is linked to the location of target antigens.　One is the pemphigus group which shows intraepidermal blister formation in histology, and their autoantibodies are raised against desmogleins, cadherin type cell-cell adhesion molecules found in desmosomes.　The other is the pemphigoid group which shows subepidermal blister formation in histology, and their autoantibodies are developed against components found in the basement membrane zone (e. g. BP180, type VII collagen, etc).　Pathogenesis, target antigens, and diagnostic tools for each autoimmune bullous disease are explained in this article.　Enzyme-linked immunosorbent assays (ELISAs) in pemphigus and bullous pemphigoid are useful not only for the diagnosis but also for the evaluation of treatment.