Two cases of pemphigus vegetans with IgG anti-desmocollin 3 antibodies.

IMPORTANCE Pemphigus vegetans shows clinically vegetating and/or pustular skin lesions mainly on the intertriginous areas and histopathologically neutrophilic and eosinophilic pustules in the epidermis. Pemphigus vegetans shows IgG reactivity mainly with desmoglein (Dsg) 3, but also with other autoantigens, including Dsg1 and desmocollins (Dscs). OBSERVATIONS We examined antigen profiles in 2 cases of pemphigus vegetans. (1) A women in her 80s presented with typical vegetating skin lesions on the right inguinal region with typical histopathological features. Immunoblotting using normal human epidermal extracts detected IgG antibodies to Dsg1 and Dscs. Enzyme-linked immunosorbent assays (ELISAs) revealed IgG antibodies to Dsg1 but not to Dsg3. Complementary DNA (cDNA) transfection method to COS-7 cells and novel ELISAs using eukaryotic recombinant proteins of human Dsc1, Dsc2, and Dsc3 confirmed specific IgG reactivity with Dsc3. (2) A women in her 70s presented with pustular skin lesions on the left fingers with typical histopathological features. Immunoblotting and ELISAs did not detect antibodies to either Dsg1 or Dsg3. Conversely, immunoblotting detected IgG antibodies to Dscs, cDNA transfection method revealed IgG reactivity only with Dsc3, and findings from ELISAs showed that IgG reacted weakly with Dsc2 and strongly with Dsc3. CONCLUSIONS AND RELEVANCE Autoantibodies to Dscs, particularly to Dsc3, may play a pathogenic role in some cases of pemphigus vegetans.