Analysis of the anti-DSG Ab levels for patients with PV revealed elevation of the mean IgG anti-DSG1 levels at T1 (221.7 U/mL with a range from 0 to 4562 U/mL) and anti-DSG3 (1450 U/mL with a range from 81 to 8841 U/mL). This evidence concerns the gene DSG1 and acquired polycythemia vera.