While some of the HLA types are more population-specific, there are others that are associated with PV across numerous ethnic groups: a link between HLA-DRB1*04:02 and DQB1*03:02 with PV in the Jewish population has been highlighted (Gazit and Loewenthal, 2005), while HLA-DQB1*05:03 was found in association with PV in non-Jewish populations (Ahmed et al., 1991). Here, HLA-DRB1 is linked to acquired polycythemia vera.