HGF and Thrombocytosis: In PV, increased macrophage inflammatory protein 1b (MIP1b) levels were correlated with shortened survival, and significant correlations were described for interferon-alpha (IFNa) and IFNg with thrombocytosis, IL-12 levels and hematocrit, as well as IL-1β, IL-2, IL-7, fibroblast growth factor b (FGFb), and hepatocyte growth factor (HGF) with leukocytosis [39].