PMF patients had a percentage of terminally differentiated EMRA cells in the CD8 compartment of 49% (IQR: 30–54), significantly higher than 26% (IQR: 15–41) in ET patients (p = 0.024) and near significantly higher than 29% (IQR: 24–38) in PV patients (p = 0.070) (Figure 3B). This evidence concerns the gene CD8A and acquired polycythemia vera.