Low Raltegravir Concentration in Cerebrospinal Fluid in Patients With ABCG2 Genetic Variants

Adenosine triphosphate-binding cassette transporter G2 (ABCG2) is expressed on the cerebrospinal fluid (CSF) side of choroid plexus epithelial cells, which form the blood-CSF barrier. Raltegravir was recently identified as a substrate of ABCG2. In the present study, we analyzed the relationship between single-nucleotide polymorphisms of ABCB1 and ABCG2 genes and raltegravir concentrations in 31 plasma and 14 CSF samples of HIV-infected patients treated with raltegravir-containing regimens. The mean CSF raltegravir concentration was significantly lower in CA (25.5 ng/mL) and AA (<10 ng/mL) genotypes at position 421 in ABCG2 gene compared with CC (103.6 ng/mL) genotype holders (P = 0.016).