Cicatricial pemphigoid sera specifically react with the most C-terminal portion of BP180

Background: cicatricial pemphigoid and bullous pemphigoid are characterized by circulating autoantibodies to the hemidesmosomal protein, BP180. Different clinical features between cicatricial pemphigoid and bullous pemphigoid appear to correlate with distinct target epitopes on BP180. Previous studies demonstrated that the majority of bullous pemphigoid sera react with immunodominant membrane-proximal non-collagenous domain (NC16a) on the extracellular portion of 1313180, whereas cicatricial pemphigoid antibodies are directed to the C-terminal domains of BP180. However, the fine sites within the C-terminal domain of BP180 recognized by autoantibodies in patients with cicatricial pemphigoid and bullous pemphigoid have not yet been clearly elucidated. Objectives: the aim of the present study was to analyze the fine specificity of the reactivity within the C-terminal domain of BP180 for the autoantibodies in sera from patients with cicatricial pemphigoid, and to compare the reactivity with that of bullous pemphigoid sera. Methods and results: we generated three recombinant proteins with 101 amino acids, which together cover the C-terminal domain of BP180. We confirmed that cicatricial pemphigoid sera mainly react with most C-terminal portion, whereas bullous pemphigoid sera react with more N-terminal domains. Conclusion: this study implicated that autoantibodies; of sera from patients with cicatricial pemphigoid and bullous pemphigoid reacted differently within C-terminal domain of BP180. (C) 2003 Japanese Society for Investigative Dermatology. Published by Elsevier Science Ireland Ltd. All rights reserved.