Role of P-glycoprotein in refractoriness of seizures to antiepileptic drugs in Lennox-Gastaut syndrome.

Mechanism of seizure refractoriness to antiepileptic drugs in children with Lennox-Gastaut syndrome is not known. Efflux of antiepileptic drugs due to increased expression/function of P-glycoprotein, a multidrug efflux transporter protein on the cell surface is a proposed mechanism. The authors studied the expression/function of P-glycoprotein on peripheral blood mononuclear cells of 29 children with Lennox-Gastaut syndrome, 23 children with other epilepsies, and 19 healthy children. The authors found a higher P-glycoprotein expression/function in Lennox-Gastaut syndrome, a higher percent positive cells as compared to children with other epilepsy (P < 0.001) and to healthy controls (P = 0.012), higher P-glycoprotein expression as compared to healthy controls (P = 0.003), a higher total P-glycoprotein expression (relative florescence intensity × percent positive cells) as compared to children with other epilepsies (P < 0.001) and healthy controls (P < 0.001), and a higher P-glycoprotein function as compared to children with other epilepsies (P = 0.001) and healthy controls (P = 0.002). These findings may explain seizure refractoriness to anti-epileptic drugs in Lennox-Gastaut syndome.