Taken collectively, the present and previous14,16–18 observations suggest that ST18 overexpression in PV skin, which is genetically determined14,16, boosts pro-inflammatory cytokine secretion and autoantibody-mediated DSG3 down-regulation, which result in impaired cell–cell adhesion within the epidermis14,16,17. This evidence concerns the gene DSG3 and acquired polycythemia vera.