title: Prevalence of X4 tropic HIV-1 variants in patients with differences in disease stage and exposure to antiretroviral therapy.
abstract: Viral tropism plays an important role in HIV pathogenesis. However, its correlation with the clinical outcome and following exposure to antiretroviral drugs are still unclear. HIV-1 co-receptor usage was examined in 206 infected individuals: 67 seroconverters, 52 chronically drug-naïve, and 87 antiretroviral-experienced patients. The V3 loop was sequenced from plasma HIV-RNA and co-receptor usage was inferred using a phenotype predictor software (http://genomiac2.ucsd.edu:8080/wetcat/v3.html), which classifies V3 sequences as R5 or X4. The overall prevalence of X4 viruses was 26.2%, with significant differences among groups: 13.4% in seroconverters, 25% in drug-naïve, and 36.8% in antiretroviral- experienced patients (P = 0.001). The presence of X4 variants in the latter group was associated with higher viral load (P = 0.002) but not with lower CD4 counts. There was no association between HIV tropism and gender, transmission route or age. Neither with the CCR5 Delta32 genotype. Moreover, no association was found between HIV-1 tropism and drug resistance mutations nor with failure to regimens based on either protease inhibitors or non-nucleoside reverse transcriptase inhibitors. Finally, no significant association was found between IL-7 plasma levels with HIV-1 tropism. In summary, X4 viruses are particularly frequent among antiretroviral-experienced patients with high viral loads, irrespective of the CD4 count. Thus, CCR5 antagonists should be used with special caution in this subset of patients.
authors.affiliation: Department of Infectious Diseases, Hospital Carlos III, Madrid, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Poveda
authors.forename: Verónica
authors.initials: V
authors.lastname: Briz
authors.forename: Carmen
authors.initials: C
authors.lastname: de Mendoza
authors.forename: José Miguel
authors.initials: JM
authors.lastname: Benito
authors.forename: Angélica
authors.initials: A
authors.lastname: Corral
authors.forename: Natalia
authors.initials: N
authors.lastname: Zahonero
authors.forename: Sara
authors.initials: S
authors.lastname: Lozano
authors.forename: Juan
authors.initials: J
authors.lastname: González-Lahoz
authors.forename: Vincent
authors.initials: V
authors.lastname: Soriano
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D024921:Drug Resistance, Multiple, Viral / Q000235:genetics; D005260:Female; D014644:Genetic Variation; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D015851:Interleukin-7 / Q000097:blood; D008297:Male; D012367:RNA, Viral / Q000097:blood; D011956:Receptors, Cell Surface; D012189:Retrospective Studies
chemical_list: D019380:Anti-HIV Agents; D015851:Interleukin-7; D012367:RNA, Viral; D011956:Receptors, Cell Surface