Additionally, in some studies, in the follow-up period of patients showing a transition from PV to PF, re-transition to PV has been observed.2, 8 Interestingly, among previously reported patients showing the transition from PV to PF, two of them had elevated levels of both anti-Dsg1 and anti-Dsg3 antibodies after the transition.6, 15 Although subtype conversion among pemphigus patients is extremely rare, the transition from PF to PV is even rarer (Table 2). This evidence concerns the gene DSG1 and acquired polycythemia vera.