Pemphigus foliaceus: preferential binding of IgG1 and C3 at the upper epidermis

The immunopathological mechanism of pemphigus foliaceus acantholysis remains controversial. Previous workers have found that IgG autoantibodies are reactive with the epidermal surface and capable of blister induction. The presence of complement components in lesions also suggests their potential role in this disease. Complement participation, however, has not been clearly demonstrated. We describe a case of pemphigus foliaceus (PF) in a 58-year old woman which was confirmed by histopathological and immunopathological studies, and by ELISA assay on recombinant PF antigen. Unusual features of this case include the predominance of IgG1 anti-epithelial antibody in both the deposits and circulation, and the preferential binding of IgG and complement component 3 at the upper epidermis. We believe that this pattern of co-localized deposition suggests a location-specific, non-random complement activation.