These antibodies are directed against various hemidesmosomal proteins: (i) type XVII collagen (BP180) in BP, MMP, pemphigoid gestationis, lichen planus pemphigoides, and LAD, (ii) BP230 in BP, (iii) laminin-332 in anti-laminin-332 pemphigoid, (iv) integrin β4 in ocular MMP, and (v) p200 in anti-p200 pemphigoid. Here, COL17A1 is linked to autoimmune bullous skin disease.