Early elevation of serum thrombopoietin levels and subsequent thrombocytosis in healthy preterm infants.
To verify pathophysiological mechanisms underlying thrombocytosis in low-birth-weight (LBW) preterm babies, we evaluated kinetic changes in platelet counts and thrombopoietic cytokines including thrombopoietin (TPO), interleukin 6 (IL-6) and IL-11 in 24 uncomplicated preterm infants. Platelet counts in cord blood (CB) (265 +/- 64 x 10(9)/l) were similar to adult levels, increased by d 14 (473 +/- 140 x 10(9)/l), and then remained fairly constant. Thrombocytosis (> 500 x 10(9)/l) was observed in 9/24 (38%) subjects. Mean TPO level in CB was 5.11 +/- 1.51 fmol/ml, peaked at d 2 (7.64 +/- 3.28 fmol/ml), decreased at d 5 (3.93 +/- 1.67 fmol/ml), and thereafter kept fairly constant during the remaining neonatal period. Compared with term infants, mean TPO levels of preterm infants in CB and at d 2 were significantly higher (P < 0.01). There was an inverse correlation between platelet counts and TPO levels (r = 0.45, P < 0.001, n = 88). Preterm neonates with thrombocytosis had significantly higher TPO values in CB than those without thrombocytosis (P < 0.05). There was no significant relationship between platelet counts and IL-6. IL-11 was not detectable. These results suggest that an early elevation of serum TPO levels is related to the subsequent thrombocytosis in LBW preterm infants.
Matsubara
K
K
Department of Paediatrics, Nishi-Kobe Medical Centre, 5-7-1 Kojidai, Nishi-ku, Kobe 651-2273, Japan. kskmatsu@portnet.ne.jp
Baba
K
K
Nigami
H
H
Harigaya
H
H
Ishiguro
A
A
Kato
T
T
Miyazaki
H
H
D015415:Biomarkers / Q000097:blood; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000097:blood*; D017370:Interleukin-11 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D010976:Platelet Count; D013922:Thrombocytosis / Q000097:blood*; D013926:Thrombopoietin / Q000032:analysis*
D015415:Biomarkers; D017370:Interleukin-11; D015850:Interleukin-6; D013926:Thrombopoietin