Elevated Interleukin-6 Levels as a Potential Marker of Neonatal Morbidity in Full-term Infants With Polycythemia: A Prospective Study.

Objective: To research and show that interleukin-6 (IL-6) and c-reactive protein (CRP), which can be used as infection markers, are also higher among newborns with polycythemia. The study took place in the neonatal intensive care unit of Zekai Tahir Burak Maternity Teaching and Research Hospital.

Patients and methods: Infants with a gestational age of >37 weeks were included in the study. Infants with chorioamnionitis, perinatal asphyxia, and positive blood culture were excluded from the study. Blood samples were obtained six hours after the delivery from the peripheral vein of the infants for measurements of central hematocrit, blood culture, IL-6, and CRP. Infants with a venous hematocrit value of >65% were grouped as the "polycythemia group," and the ones with a venous hematocrit value of <65% were designated as the "control group." Observation of significantly higher levels of CRP and IL-6 among newborns admitted to the neonatal intensive care unit due to different causes (such as respiratory distress, hypoglycemia, and feeding intolerance), but significantly higher IL-6 levels in newborns with polycythemia.

Results: Thirty-five newborns (18 infants in the polycythemia group and 17 infants in the control group) were enrolled in the study. The IL-6 values for the polycythemia group were higher than the upper normal limits (mean ± 2SD, 37.6 ± 55 vs 12 ± 5 pg/dL, respectively; P = 0.00). The IL-6 values of the polycythemia group were found to be higher than the IL-6 values of the control group, with a mean ± 2SD of 37.6 ± 55 vs 6.3 ± 3.4 pg/dL, respectively; this was significant (P = 0.00). Although the CRP values of the polycythemia group were found to be slightly higher than those of the control group (a mean ± 2SD of 3.06 ± 4.07 vs 1.54 ± 2.21 mg/dL, respectively, P > 0.05), this was not significant.

Conclusions: This study found a significant and robust statistical correlation between IL-6 and v. Hct values (P = 0.01, rs = 0.641). Contrary to IL-6 levels, however, a meaningful relationship was not found between CRP and v.htc values (P = 0.286; rs = 0.184).