In order to conform to the postulates of the DCH, PF patients would be expected to only have detectable anti-Dsg1 antibodies, mucosal PV patients should only have detectable anti-Dsg3 antibodies, and mucocutaneous PV would be expected to harbor both anti-Dsg3 and anti-Dsg1 antibodies. This evidence concerns the gene DSG3 and acquired polycythemia vera.