Does polycythemia affect interleukin-6 response pattern in early postnatal period?

Neonatal polycythemia may result in increased cytokine production. We aimed to investigate whether polycythemia and partial exchange transfusion (PET) affect interleukin-6 (IL-6) response pattern in early neonatal period.

Ninety-four newborns, 57 with polycythemia (Group 1) and 37 as control group (Group 2) were enrolled in the study. PET was performed at 4-6 hr following birth in the first group. Blood levels of IL-6 were measured at 2-4 hr following birth; measurements were repeated at 6 and 24 hr after PET in newborns with polycythemia and at similar hours in Group 2. In Group 1, two patients (3.5%) who were diagnosed with proven sepsis excluded from the study.

Both initial and the last IL-6 levels were higher in Group 1 (21.7; 5.5-190 pg/ml and 18.3; 2.7-92.4 pg/ml) than those of the controls (8.4; 0.2-47.8 pg/ml and 8.6; 2.0-21.0 pg/ml) (P=0.001 for both comparisons). In Group 1, IL-6 levels increased at 6 hr after PET and decreased thereafter. IL-6 showed the same pattern in the control group. IL-6 levels were higher than >70 pg/ml in two (3.6%), seven (12.7%), and two (3.6%) subjects during three evaluation steps, respectively. Neither clinical nor proven sepsis was subsequently detected in any of these subjects. IL-6 levels were within the acceptable values in Group 2.

IL-6 levels seem to be high in newborns with polycythemia during the first days of life, although they rarely exceed maximum acceptable levels. The pattern of IL-6 response might be taken into account to optimize its use in the diagnosis of early-onset neonatal sepsis.