In two separate studies that compared children with TBI to age-matched controls (children without TBI who needed lumbar puncture for obstructive hydrocephalus treatment or meningitis rule-out), higher cerebrospinal fluid (CSF) and serum levels of nerve growth factor (NGF), IL-1β, and IL-6 correlated with more severe head injury and worse clinical outcomes (21, 22). Here, NGF is linked to infectious meningitis.