title: Elevation of serum thrombopoietin precedes thrombocytosis in acute infections.
abstract: To clarify the mechanisms underlying thrombocytosis secondary to infections, we longitudinally studied serum levels of thrombopoietin (TPO) and interleukin (IL)-6 in 15 infants and young children with prominent thrombocytosis (platelets >700 x 10(9)/l) following acute infections and 116 age-matched controls using an enzyme-linked immunosorbent assay. The subjects included nine patients with bacterial infections, three with viral infections and three with non-determined pathogens. TPO values in the controls were 2.24 +/- 0.87 fmol/ml (mean +/- SD) with a 95% reference interval of 0.85-4.47 fmol/ml. In the first week of infection, platelet counts were normal, but TPO values increased (approximately 10.73 fmol/ml). TPO levels peaked on day 4 +/- 2 at 6.44 +/- 2.37 fmol/ml and then fell gradually. When platelet counts peaked in the second and third weeks, TPO levels were similar to the controls. IL-6 levels in the first week rose and dropped more rapidly than TPO. Serum TPO values were significantly correlated with C-reactive protein levels (r = 0.688, P < 0.001) and IL-6 levels (r = 0.481, P = 0.027). These results suggest that TPO contributes to thrombocytosis following infections in conjunction with IL-6, arguing for additional regulatory mechanisms of blood TPO levels.
authors.affiliation: Department of Paediatrics, Mizonokuchi Hospital, Teikyo University School of Medicine, Kawasaki, Japan. ishiguro@med.teikyo-u.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Ishiguro
authors.forename: Yoko
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Mari
authors.initials: M
authors.lastname: Mito
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Shimbo
authors.forename: Kousaku
authors.initials: K
authors.lastname: Matsubara
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyazaki
mesh_terms: D000208:Acute Disease; D002097:C-Reactive Protein / Q000378:metabolism; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007239:Infections / Q000097:blood / Q000150:complications*; D015850:Interleukin-6 / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D010976:Platelet Count; D012016:Reference Values; D013922:Thrombocytosis / Q000097:blood* / Q000382:microbiology*; D013926:Thrombopoietin / Q000097:blood*
chemical_list: D015850:Interleukin-6; D002097:C-Reactive Protein; D013926:Thrombopoietin