Usefulness of thrombopoietin and IL-6 serum levels in thrombocytopenic newborn

ABSTRACT

Thrombocytopenia remains a common problem in sick newborns. A quarter of all neonates admitted to neonatal intensive care units develop thrombocytopenia and in 20% of neonatal bleeding episodes, the thrombocytopenia is severe [platelets < 50.000/mm[3]]. Thrombopoietin [TPO] regulates platelets production stimulating megakaryocyte prolieration and mutation. Interleukin 6 [IL-6] is one of the most potent thrombopoietin cytokines. Establishment of thrombopoietin and IL-6 serum levels in healthy and thrombocytopenic neonates is an important step in further understanding of the pathophysiology of neonatal thrombocytopenia. We measured circulating TPO and IL-6 in groups of neonates with thrombocytopenia to find out if mey have a role in thrombopoiesis and to determine their value in diagnosis of several of thrombocytopemu. One hundred and five newborns with thrombocytopenia [47 fullterm and 58 preterms] were the study population. Their ages ranged between 1 and 29 days [2.8 +/- 4.5]. Thirty age and sex - matched healthy newborns constitute the control group. Half of them were preterm and other half were fullterm. Serum TPO and IL-6 levels were measured by enzyme-linked immunoassay [ELISA]. Thrombocytopenia patients had higher serum TPO and IL-6 levels [575.04 +/- 430.7 pg/ml, 112.83 +/- 128.83 pg/ml respectively] than the control group [301 +/- 112.48 pg/ml, 61.9 +/- 73.28 pg/ml] and the difference was statistically highly significant [p < 0.001]. TPO and IL-6 serum levels showed positive significant correlation [r =0.25. p = 0.003]. In thrombocytopenia neonates, the lower the platelet count, the higher the serum TPO concentration. The differences for serum Il-6 levels in fullterm and preterm thrombocytopenic neorates when compared to healthy fullterm and preterm controls were statistically significant [P = 0.02, 0.007 respectively] while those for serum TPO levels gave insignificant results [P = 0.3 and 0.07]. Thrombocytopenic neonates with sepsis had higher and significant TPO and IL-6 serum levels than thrombocytopenic neonates with other etiologies and controls [633.68 +/- 406.58, 333.04 +/- 203.39, P < 0.0001]. Measurements of serum TPO and IL-6 levels provide valuable diagnostic information for the analyses of thrombocytopenia in neonatal infants