DSG1 and acquired polycythemia vera: Interestingly, we also observe a trend toward a higher prevalence of anti-TPO and anti-Tg antibodies in PV patients with the rare “cutaneous only” phenotype and a significant increase in anti-Tg in anti-Dsg1/3 double-negative patients in active disease vs. remission, suggesting that the “supporting role” anti-thyroid antibodies may play in disease pathogenesis is more pronounced in less common disease phenotypes.