IL17A and acquired polycythemia vera: Regarding the correlation of cytokines among PV patients, IL-6 was found to be positively correlated with IL-17 (r = 0.4263, p ≤ 0.01) and IL-23 (r = 0.5005, p < 0.001), but negative correlated with TGF-β (r = −0.3989, p<0.01) (Figure 2).