COL17A1 and mucous membrane pemphigoid: The present review focuses on BP180, the main autoantigen of the DEJ, and highlights the fine autoantibody specificities against this autoantigen targeted in four PD, i.e. bullous pemphigoid (BP), mucous membrane pemphigoid (MMP), linear IgA dermatosis, and pemphigoid gestationis (16, 17).