In PG, antibodies are mainly directed against the same BP180 epitopes as in bullous pemphigoid [23,24]: most commonly against the epitopes found in NC16A, the largest non-collagenous domain of BP180, but antibodies against intracellular BP180 domains and other extracellular domains of BP180 have also been observed [25]. This evidence concerns the gene COL17A1 and bullous pemphigoid.