The upregulation of KNG levels in the CSF but not in the peripheral blood during epileptogenesis, both in LiCl-Pilo model rats and in patients with encephalitis with concomitant secondary epilepsy, together with the increase in the hippocampal KNG level in LiCl-Pilo rats, suggested that the upregulation of KNG level in the CSF may resulted from increased intra-cerebral synthesis. This evidence concerns the gene KNG1 and viral encephalitis.