Analyses of autoantigens in a new form of endemic pemphigus foliaceus in Colombia

Background. We previously described a new focus of endemic pemphigus foliaceus in rural areas of El Bagre, Colombia, with clinical and direct immunofluorescence characteristics of pemphigus erythematosus. Objective: The aim of this study was to characterize autoantigen profiles for 34 serum samples obtained from patients with this condition. Methods: Immunofluorescence, various immunoblot analyses with different antigen sources and detection methods, and immunoprecipitation were performed. Results: Immunofluorescence with the use of human skin sections showed IgG autoantibodies against keratinocyte cell surfaces in all 34 serum samples. Some samples also showed weak reactivity with the basement membrane zone. The results of immunoblot and immunoprecipitation analysis indicated that all sera had antibodies reactive with desmoglein 1, the pemphigus foliaceus antigen. In addition, in various immunoblot assays, many sera reacted with several other proteins with molecular weights of 250 kd, 210 kd, and 190 kd, which appear to correspond to desmoplakin I, envoplakin, and periplakin, respectively. Conclusion: This endemic pemphigus disease in El Bagre showed immunologic features similar to pemphigus foliaceus or erythematosus. In addition, paraneoplastic pemphigus-like reactivity with various epidermal antigens was detected.