In addition, the levels of several inflammatory cytokines, such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1β, and IL-18, are increased in the cerebrospinal fluid (CSF) of patients affected by bacterial meningitis (Geldhoff et al., 2013; Chong et al., 2018). Here, TNF is linked to bacterial meningitis.