BP180 Autoantibodies Target Different Epitopes in Multiple Sclerosis or Alzheimer’s Disease than in Bullous Pemphigoid

Neurological patients have an increased risk for bullous pemphigoid (BP) in which autoantibodies target BP180, a cutaneous basement membrane protein also expressed in the brain. Here we show that 53.6% sera of patients with multiple sclerosis (MS) (n=56) had IgG reactivity against full-length BP180 in immunoblotting, while in BP180-NC16A ELISA (n=143), only 7.7% MS samples studied were positive. Epitope mapping with 13 fusion proteins covering the entire BP180 polypeptide revealed that, in MS and Alzheimer's disease (AD) patients, IgG autoantibodies target regions located in the intracellular and mid-extracellular parts of BP180, but not the well-known BP epitopes located in the NC16A domain and the distal part of extracellular domain.