DSG1 and acquired polycythemia vera: Immunoadsorption of pathologic auto-abs from PV sera using the entire EC domains of Dsg1 and Dsg3 abolished the blister-inducing ability of IgG fractions in mice, suggesting that anti-Dsg1/3 IgG alone is pathogenic; other factors such as additional non-desmoglein PV auto-abs alone or in combination are not required (47, 48).