Higher levels of soluble IL‐2Rα (sIL‐2Rα) have also been observed in patients with myelofibrosis relative to either patients with polycythaemia vera (PV)/ET or healthy controls8 and increased IL‐6, IL‐2 and sIL‐2Rα have been demonstrated in patients following progression from ET and PV to myelofibrosis.23 This evidence concerns the gene IL2RA and acquired polycythemia vera.