Bullous Pemphigoid: IGA Autoantibodies Target Epitopes on of Bullous Pemphigoid Antigen 180 Using Recombinant Ectodomains of Collagen XVII

Type XVII collagen (BP180), promotes adhesion of basal keratinocytes to epidermal basement membrane, and is the target of disease in patients with certain inherited or acquired blistering diseases. Therefore, the aim of the present study was to investigate IgA autoantibodies using recombinant BP 180 proteins against bullous pemphigoid in the sera of patients. Thirty consecutive BP sera were analyzed by ELISA and western blotting using highly purified recombinant subdomain forms of the collagen XVII proteins. We have recombinantly produced of the collagen XVII ecto-subdomains in a mammalian expression system (BP180-A, B, C and D). The patients Sera with bullous pemphigoid mainly react with epitopes clustered within the NC16A and the NC1, C-terminal domains of BP180. Interestingly, out of 30 patients with BP, the sera of 25 reacted with recombinant BP 180 (A, B and C), and the sera of 22 reacted with BP 180-D. The bullous pemphigoid patients sera reacted with the recombinant BP180 ectodomain (A, C and D). Therefore, a sensitivity of 86. % with BP180 (A and C) and 73 % with BP180-D, resulted for the ELISA. Our results demonstrate that autoantibodies in BP target epitopes of subdomains of BP180 ectodomain.