Validation of raised cord blood interleukin-16 in perinatal asphyxia and neonatal hypoxic-ischaemic encephalopathy in the BiHiVE2 cohort

The role of inflammation is an important factor in the progression of hypoxic-ischaemic encephalopathy (HIE). We have previously shown that interleukin-16 (IL-16) is increased in infants with moderate and severe HIE and relates to poor neurodevelopmental outcomes. We aimed to validate IL-16 as a cord blood-based biomarker for HIE and to examine its relationship to long-term outcomes. The study sample consisted of 105 full-term infants who experienced perinatal asphyxia (PA) (with and without an encephalopathy) along with healthy, gestational age-matched newborn controls. Umbilical cord blood serum was processed and biobanked at delivery. Infants were assigned a modified Sarnat score at 24 h. Analysis of IL-16 cytokine cord blood levels was performed using the sandwich-based enzyme-linked immunosorbent assay (ELISA) technique. Cord blood-based IL-16 was increased in infants with PA and HIE relative to controls (p = 0.025). IL-16 was also increased in the HIE group relative to controls (p = 0.042). There was no significant difference in IL-16 across grades of HIE or in those with abnormal outcomes at 2 years of age. This study validates findings that cord blood-based IL-16 levels are increased in infants with PA, including those who go on to develop HIE.