MPN monocytes have defective IL-10 signaling. (A) MPN (n = 9 PV, 6 ET, and 4 MF) and normal (n = 18) peripheral blood was stimulated for 15 minutes with IL-10 at the concentrations shown before fixation and permeabilization. CD33 ^high Cd14⁺ monocytes were gated for pStat3 and analyzed via flow cytometry. (B) MPN (n = 2 PV and 1ET) and normal (n = 3) monocytes were stimulated with IL-10 for 15 minutes, 1 hour, or 2 hours at the concentrations shown. SOCS3 mRNA was quantified by quantitative PCR and normalized to β-actin. *P < .05.