IL9 and acquired polycythemia vera: Despite these inter-individual differences, our analysis uncovers a pronounced dysregulation of multiple cytokine immune pathways in PV compared to healthy controls, namely with elevation of the Th2 cytokines IL-4 and IL-5, the Th17 cytokines IL-22 and IL-23, as well as IL-2, IL-9, IL-10 and IL-15.