IgA autoantibodies against the NC16a domain of BP180 but not 120-kDa LAD-1 detected in a patient with linear IgA disease.

摘要

Sir, Linear IgA disease (LAD) is an autoimmune subepidermal bullous disease characterized by linear deposits of IgA autoantibodies at the cutaneous basement membrane zone (BMZ). LAD displays two major binding patterns of patients' IgA autoantibodies, i.e. indirect immunofluorescence on NaCl-split skin reveals that most LAD sera of lamina lucida type react with the epidermal side, and a few LAD sera of sublaminadensa type react with the dermal side. Most patients with the lamina lucida type of LAD show IgA autoantibodies against the 97-kDa protein LABD97 and the 120-kDa protein LAD-1, both of which are degradation products of the extracellular domain of the 180-kDa bullous pemphigoid antigen (BP180, type XVII collagen). We report a case of LAD in which immunoblot analysis demonstrated that autoantibodies react with the NCl 6a domain of BP180, which is the major region recognized by IgG autoantibodies in patients with bullous pemphigoid.