KITLG and myeloproliferative disorder: The authors observed that both serum and bone marrow Thrombopoietin (TPO), IL-6, soluble (s) IL-6 receptor (R), IL-8, and Stem Cell Factor (SCF) were increased in MPN patients or subjects with reactive thrombocytosis as compared to healthy controls, with IL-6 significantly increased in clonal vs. reactive disorders, and SCF and IL-8 selectively elevated in clonal thrombopoiesis [61].