In fact, linear depositions of autoantibodies or C3 at the DEJ were demonstrated in six out of twelve cases recorded as “BP during CI therapy.” It must be borne in mind that these minimal requirements do not allow a clear distinction between BP and other pemphigoid diseases such as the inflammatory variant of epidermolysis bullosa acquisita and anti-p200 pemphigoid, which cannot be clearly distinguished from BP by the clinical presentation alone. This evidence concerns the gene C3 and autoimmune bullous skin disease.