Immunoblot analysis of autoantigens in localized pemphigoid and pemphigoid nodularis.

We analyzed circulating antibodies in sera from patients with localized pemphigoid and pemphigoid nodularis, two variants of bullous pemphigoid, by means of western immunoblotting of human epidermal extracts and the recombinant protein of NC16a domain of the 180 kD bullous pemphigoid antigen. NC16a domain is now considered to be the most pathogenic site of bullous pemphigoid. Compared with the results of typical bullous pemphigoid patients, localized pemphigoid sera detected the 180 kD bullous pemphigoid antigen less frequently, and sera from both localized pemphigoid and pemphigoid nodularis showed a lower end point of titer of antibodies to NC16a domain. These results suggest that atypical clinical features of the two bullous pemphigoid variants may be related with low titer of autoantibodies to 180 kD bullous pemphigoid antigen, particularly to NC16a domain.