Comparative study of autoantigen profile between Colombian and Brazilian types of endemic pemphigus foliaceus by various biochemical and molecular biological techniques

Background: Besides Brazilian endemic pemphigus foliaceus (EPF), we have described another focus of EPF in Colombia. Our previous study suggested that Colombian EPF seemed to react various plakin family proteins, such as envoplakin, periplakin and BP230. Objective: To further characterize the Colombian EPF and study the difference from Brazilian EPF, we examined the antigen profile of the two types of EPF. Methods and results: Immunoblotting using normal human epidermal extracts revealed that 38% Colombian EPF sera and 25% Brazilian EPF sera showed IgG antibodies reactive with desmoglein (Dsg) 1, pemphigus foliaceus antigen. The sera of both types of EPF showed protein bands co-migrating with plakin family proteins, particularly periplakin. Immunoblotting analyses using recombinant proteins of various domains of envoplakin, periplakin and BP230 revealed that a considerable number of Colombian EPF sera reacted with recombinant proteins of periplakin, while only few Brazilian sera reacted with some of the recombinant proteins of any plakins. Enzyme-linked immunosorbent assay (ELISA) for Dsg1 and Dsg3 showed that Dsg1 was reacted by almost all sera of both types of EPF. However, unexpectedly, while none of Colombian EPF sera reacted with Dsg3, about half of Brazilian EPF sera reacted with Dsg3. Conclusion: These results suggested that the Colombian EPF is basically similar to Brazilian EPF in terms that major antigen is Dsg1, but there were some different antigen profiles between the two types of EPF.