TLR4 and epilepsy: A number of studies have shown a correlation between the severity of epileptic seizures and increased levels of cytokines in the blood plasma (HMGB-1, TLR4, IL-1β, IL-1R1, and TNF-α) of patients with drug-resistant epilepsy [17,27]; increased levels of cytokines have also been observed in cerebrospinal fluid (IL-1β) [16,28].