IL17A and acquired polycythemia vera: The numbers of IL-23+ cells and IL-17+ cells were significantly increased in PV lesions (Figures 1(a)–1(d) and Figures 2(a)–2(d)), compared to healthy controls (Figures 1(e)–1(h); Figures 2(e)–2(h); Figure 3, P < 0.05).