title: R5 to X4 switch of the predominant HIV-1 population in cellular reservoirs during effective highly active antiretroviral therapy.
abstract: HIV-1 coreceptor usage plays a critical role for virus tropism and pathogenesis. A switch from CCR5 to CXCR4-using viruses can occur in the natural course of infection and correlates with subsequent disease progression. To investigate whether HIV-1 genetic evolution might lead to changes in virus coreceptor usage during highly active antiretroviral therapy (HAART), a longitudinal genotypic analysis of the virus found in cellular reservoirs was conducted in 32 patients with undetectable viral loads on HAART for 5 years. The genotype of the 3rd variable region of the env gene predicting coreceptor usage was retrospectively determined in the plasma or in peripheral blood mononuclear cells (PBMC) at baseline and then in PBMCs at months 30 and 60 of HAART. There was a switch from R5 to X4 variants in 11 of the 23 patients who harbored a majority virus population of R5 variants at baseline. X4 variants remained predominant in the 9 patients who harbored mainly X4 variants at baseline. The patients harboring predominantly X4 variants during HAART, either from baseline or after an R5 to X4 switch, tended to have lower CD4+ T-cell counts on HAART than did patients harboring continuously a majority population of R5 variants. These results suggest that potent antiretroviral therapy produces the conditions necessary for the gradual emergence of X4 variants in cellular reservoirs.
authors.affiliation: The Laboratory of Virology, Purpan University Hospital, Toulouse, France. izopet@cict.fr
authors.forename: Pierre
authors.initials: P
authors.lastname: Delobel
authors.forename: Karine
authors.initials: K
authors.lastname: Sandres-Sauné
authors.forename: Michelle
authors.initials: M
authors.lastname: Cazabat
authors.forename: Christophe
authors.initials: C
authors.lastname: Pasquier
authors.forename: Bruno
authors.initials: B
authors.lastname: Marchou
authors.forename: Patrice
authors.initials: P
authors.lastname: Massip
authors.forename: Jacques
authors.initials: J
authors.lastname: Izopet
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy* / Q000821:virology; D000328:Adult; D000595:Amino Acid Sequence; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D004197:Disease Reservoirs; D005260:Female; D015686:Gene Products, env / Q000097:blood / Q000737:chemistry / Q000235:genetics; D015752:Genes, env; D014644:Genetic Variation; D005838:Genotype; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000097:blood / Q000302:isolation & purification; D019562:Viral Load
chemical_list: D015686:Gene Products, env; D012367:RNA, Viral