IL17A and acquired polycythemia vera: In this study, we examined the immunoexpression of IL-23 and IL-17 in the lesional biopsy specimens from 10 cases of PV, comparing the results with those of PF patients and normal control skins from 6 healthy individuals, and evaluated the correlation between IL-23+ cells and IL-17+ cells; moreover, the sources of IL-23 were also evaluated.