title: Blood thrombopoietin levels in clonal thrombocytosis and reactive thrombocytosis.
abstract: BACKGROUND
  Although the distinction between clonal and reactive thrombocytosis is clinically relevant because clonal thrombocytosis has more thrombohemorragic complications, the differential diagnosis of these two entities can be difficult. Methods such as the detection of unstimulated erythroid or megakaryocyte colony growth are not readily available. Therefore, we measured blood thrombopoietin levels to determine whether these levels can be used to distinguish the two conditions.
  
  
  METHODS
  Thrombopoietin levels were measured in 73 patients with thrombocytosis (platelet count > 500,000/microL), including 39 patients with clonal thrombocytosis (20 patients with essential thrombocythemia, 15 with agnogenic myeloid metaplasia, 1 patient with polycythemia vera, and 3 with undefined myeloproliferative disorders) and 34 patients with reactive thrombocytosis (17 with malignant tumors, 11 with inflammatory diseases, 4 with sickle cell disease, and 2 with iron deficiency anemia). Seventeen normal volunteers were used as controls.
  
  
  RESULTS
  Thrombopoietin levels were significantly higher (P < 0.05) in patients with clonal thrombocytosis (mean +/- SD of 555 +/- 585 pg/mL), including the subgroup with essential thrombocythemia (505 +/- 459 pg/mL), than in patients with reactive thrombocytosis (290 +/- 133 pg/mL) who had similar levels as controls (201 +/- 112 pg/mL). Thrombopoietin levels in patients with clonal thrombocytosis, including essential thrombocythemia, were not correlated with platelet counts.
  
  
  CONCLUSIONS
  Thrombopoietin levels may be helpful in distinguishing between clonal thrombocytosis and reactive thrombocytosis. Thrombopoietin is probably responsible for the elevated platelet counts in clonal thrombocytosis including essential thrombocythemia, but not in reactive thrombocytosis. High thrombopoietin levels in patients with clonal thrombocytosis cannot be explained solely by platelet megakaryocyte mass.
authors.affiliation: Division of Medical Oncology and Hematology, Brookdale University Hospital and Medical Center, Brooklyn, New York 11212, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Wang
authors.forename: C
authors.initials: C
authors.lastname: Chen
authors.forename: A D
authors.initials: AD
authors.lastname: Novetsky
authors.forename: S M
authors.initials: SM
authors.lastname: Lichter
authors.forename: F
authors.initials: F
authors.lastname: Ahmed
authors.forename: N M
authors.initials: NM
authors.lastname: Friedberg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018798:Anemia, Iron-Deficiency / Q000150:complications; D000755:Anemia, Sickle Cell / Q000150:complications; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007249:Inflammation / Q000150:complications; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D010976:Platelet Count; D011087:Polycythemia Vera / Q000150:complications; D055728:Primary Myelofibrosis / Q000150:complications; D015203:Reproducibility of Results; D013920:Thrombocythemia, Essential / Q000150:complications; D013922:Thrombocytosis / Q000097:blood* / Q000145:classification / Q000175:diagnosis / Q000209:etiology*; D013926:Thrombopoietin / Q000097:blood*
chemical_list: D013926:Thrombopoietin