title: Elevated serum interleukin-6 levels in patients with reactive thrombocytosis.
abstract: Interleukin-6 (IL-6) is known to promote megakaryocytopoiesis in vitro and raise platelet counts in vivo. To determine if there is a relationship between circulating IL-6 and thrombocytosis in man, we measured bioactive IL-6 in the serum of 13 patients with myeloproliferative disorders and 143 patients with reactive thrombocytosis having platelet counts greater than or equal to 600 x 10(9)/l. IL-6 activity was assayed using the IL-6-responsive B9 cell line. Seventy-one controls with normal platelet counts had a mean IL-6 level of 2.19 U/ml +/- 1.08 (SD). None of the 13 patients with myeloproliferative disorders had elevated IL-6 levels (1.56 U/ml +/- 1.2). In contrast, serum IL-6 levels of 143 patients (158 samples) with reactive thrombocytosis were significantly greater than controls (38.3 U/ml +/- 94.6; P less than 0.001), with 83% of the samples showing elevated serum IL-6. No significant correlation was observed between serum IL-6 levels and platelet counts in the reactive thrombocytosis group. We conclude that elevated IL-6 is associated with reactive thrombocytosis, and hypothesize that the increased platelet count in many cases is causally related to elevated IL-6.
authors.affiliation: University of Oklahoma Health Sciences Center, Oklahoma City 73190.
authors.forename: C W
authors.initials: CW
authors.lastname: Hollen
authors.forename: J
authors.initials: J
authors.lastname: Henthorn
authors.forename: J A
authors.initials: JA
authors.lastname: Koziol
authors.forename: S A
authors.initials: SA
authors.lastname: Burstein
mesh_terms: D006801:Humans; D015850:Interleukin-6 / Q000032:analysis*; D009196:Myeloproliferative Disorders / Q000276:immunology; D010976:Platelet Count; D013920:Thrombocythemia, Essential / Q000276:immunology; D013922:Thrombocytosis / Q000097:blood / Q000276:immunology*
chemical_list: D015850:Interleukin-6