Clinical phenotype and anti-desmoglein autoantibody profile in paraneoplastic pemphigus

Background: Paraneoplastic pemphigus (PNP) has similar features to pemphigus vulgaris (PV), including circulating anti-desmoglein (Dsg) IgG as pathogenic autoantibodies. When PV is divided into mucosal dominant type and mucocutaneous type, mucosal dominant type has only anti-Dsg3 IgG, whereas the mucocutaneous type has both anti-Dsg3 and anti-Dsg1 IgC. Objective: The purpose of this study was to determine whether there is a difference in anti-Dsg autoantibody profile between mucosal dominant PNP and mucocutaneous PNP. Methods: Twenty-one patients with PNP were categorized as mucosal dominant and mucocutaneous types based on clinical information. Antibody titers against Dsg3 and Dsg1 were measured by enzyme-linked immunosorbent assay by means of recombinant Dsg1 and Dsg3. Results: There were 9 cases of mucosal dominant type and 12 cases of mucocutaneous type. Eight of 9 cases of mucosal dominant type were positive for anti-Dsg3 IgG, but 3 of them were also positive for anti-Dsg1 IgG. All 12 cases of mucocutaneous type were positive for anti-Dsg3 IgG, whereas only 6 of them were positive for anti-Dsg1 IgG. Conclusion: There was no clear association between the clinical phenotype and anti-Dsg antibody profile in PNP as seen in PV. This finding suggests that besides anti-Dsg IgG other pathologic mechanisms such as lichenoid reaction or interface dermatitis may be involved in the blister formation in PNP.