Several studies have indicated the importance of T cells in pemphigus (26, 27) and the role of Dsg3-specific CD4+ T cells has been elegantly demonstrated in an animal model by inducing a phenotype of interface dermatitis and PV (28), and defective regulatory T (Treg) cells may play a role in the onset of pemphigus by modulating the production of anti-Dsg3 autoantibodies (29). Here, DSG3 is linked to acquired polycythemia vera.