The Influence of Phototherapy on Serum Cytokine Concentrations in Newborn Infants

We sought to determine cytokine response in term and late preterm newborn infants on phototherapy. Twenty newborn infants with gestational age >= 35 weeks and birth weight >= 2000 g in the first week of life had serum interleukin (IL)-6, IL-8, IL-10, IL-1 beta, and tumor necrosis factor (TNF)-alpha measured immediately prior to and after 24 hours on phototherapy. Exclusion criteria were newborns with severe congenital malformations, congenital infections, birth asphyxia, sepsis, hemolytic anemia that required blood transfusion, maternal-infant Rh incompatibility and those who required exchange transfusion or intravenous immunoglobulin treatment for hyperbilirubinemia. Median IL-6 concentrations significantly decreased after 24 hours on phototherapy (18.3 pg/mL and 7.85 pg/mL, respectively, p=0.005). IL-6 concentrations decreased in 17 out of the 20 newborns. There were no statistical differences in IL-8, IL-10, IL-1 beta, and TNF-alpha concentrations before and after 24 hours on phototherapy. There was a statistically significant correlation between IL-6 decline and irradiance (r=0.57, p=0.009). The finding that serum IL-6 decreases in newborn under phototherapy suggests that phototherapy possibly has an anti-inflammatory effect, although the clinical implications of this study deserve further studies.