As shown in Fig. 1A, IL-29 serum levels in patients with PV (41.62 ± 23.26 ng/mL) were significantly higher than those in AD patients (24.35 ± 12.57 ng/mL) and control group (29.83 ± 19.52 ng/mL). Here, IFNL1 is linked to acquired polycythemia vera.