COL17A1 and Autoimmunity: Knowing that Treg activity and IL-17-producing cells may have opposite effects on autoimmunity (51, 52), an impaired Treg activity in an IL-17/IL-23 context (53, 54) could result in an imbalance between the pro-inflammatory and the regulatory cytokines levels which control the tolerance breakdown limit and therefore favors the production of anti-type VII collagen AAb and the sustained concentration of anti-BP180 AAb (47, 53, 55–57).