Endemic pemphigus foliaceus in the Peruvian Amazon.

BACKGROUND: Endemic pemphigus foliaceus (EPF) is an organ-specific blistering disease of the epidermis characterized by the presence of IgG autoantibodies, specifically desmoglein (Dsg)1. This condition has been reported particularly in Brazil, Colombia, Tunisia and Peru.

AIM: To characterize the humoral response against Dsg1 and Dsg3 autoantibodies of patients with EPF from the Peruvian Amazon region.

METHODS: Blood samples were collected from 16 patients with a clinical diagnosis of EPF, and tested using indirect immunofluorescence (IIF), immunoprecipitation and ELISA (for IgG and its subclasses against Dsg1 and IgG against Dsg3).

RESULTS: Autoantibodies against the intercellular spaces were detected by IIF in 82.5% and 87.5% of patients, using normal human skin and monkey oesophagus, respectively. Sera from all patients immunoprecipitated recombinant Dsg1, and three serum samples immunoprecipitated recombinant Dsg3 (6.25%). Using ELISA, anti-Dsg1 antibodies were detected in 13 patients (81.25%), and both IgG1 and IgG2 antibodies against Dsg1 in 12 patients (75%). All patients were positive for IgG4 autoantibodies, and only one patient was positive for IgG3 autoantibodies (6.25%). Anti-Dsg3 antibodies were detected in five patients (31.25%).

CONCLUSIONS: EPF from Peru shares epidemiological, clinical and immunological characteristics with other forms of EPF that have been described in South America.