Expression of CD95 and TRAIL receptors and effectors in normal and PV erythroblasts. Erythroid precursors derived from CD34⁺ cells of healthy donors (N) and patients with PV (PV) were cultivated in standard erythroid medium and, at day 8 of differentiation, analyzed for membrane expression of CD95 (A), TRAIL receptor-1 (B), and TRAIL receptor-2 (C). Data are representative of the results obtained with the 13 patients with PV shown in the previous figures. (D) Western blot analysis of the CD95 signal transducers FADD, caspase-3, and caspase-8. Results shown are representative of experiments performed with erythroblasts derived from CD34⁺ cells of 5 healthy donors and 9 patients with PV.