Cytokines, such as IL-6 (15, 29, 49), IL-8 (21, 49), and IL-10 (49, 50), were the first peripheral blood and cerebrospinal fluid biomarkers described for HIE (51), but validation against multiple indicators of severity of HI in a longitudinal infection-adjusted model relative to TH has not been done in a cohort this large. This evidence concerns the gene IL6 and infection.