Thrombopoietin levels of thrombocytopenic term and preterm newborns with infection

We measured Thrombopoietin (Tpo) levels in thrombocytopenic term and preterm babies with infection to investigate the relationship between thrombopietin levels and platelet counts. Sixteen preterm (27-34 weeks' gestational age) and 5 term neonates (38-41 weeks' gestational age) with the diagnosis of neonatal infection and thrombocytopenia (platelets <150 x 10(9)/L) but, without the evidence of disseminated intravascular coagulation, were prospectively enrolled in the study. Fifteen preterm (27-34 weeks' gestational age) and 9 term (38-40 weeks' gestational age) age-matched healthy neonates were enrolled in the study as control. Blood samples were obtained from each subject at the time when infection and thrombocytopenia were detected and stored until assay. Bacterial infection was confirmed by blood cultures in five patients and by tracheal cultures in five. Median Tpo levels of term controls were lower than those of preterm controls (62 pg/mL vs. 87 pg/mL) (p <0.05). Median Tpo levels of thrombocyopenic preterm patients were higher than the levels of healthy preterms (258 pg/mL vs. 87 pg/mL) (p <0.05). Similarly, median Tpo levels of sick terms were significantly higher than those of healthy term controls (209 pg/mL vs. 62 pg/mL) (p <0.001). There was not significant difference between the median Tpo levels of term and preterm babies with infection (258 pg/mL vs. 209 pg/mL) (p >0.05). There was no correlation between platelet counts and Tpo levels in both term and preterm groups. The results of our study show that healthy term and preterm babies have detectable levels of Tpo and preterm babies have higher Tpo levels than term infants. Although thrombocytopenic babies with infection have increased levels of Tpo, these levels are still lower than the levels of thrombocytopenic children/adult patients and there seems to be no correlation between platelet counts and thrombopoietin levels. So our observation of increased Tpo levels may still be inadequate for normal platelet production in this period. and this group of babies may also be candidates for the administration of recombinant human Tpo.