THPE075 - Poster Exhibition
Prevalence of R5-tropic viruses in a large cohort of HIV-1 patients: which are the current determinants of viral tropism?
E. Seclén1, V. Soriano1, M.M. González1, M. Lapaz1, J.J. Rodríguez-Calviño2, A. Aguilera2, C. De Mendoza1, E. Poveda1
1Hospital Carlos III, Department of Infectious Diseases, Madrid, Spain, 2Hospital de Conxo-CHUS, Department of Microbiology, Santiago de Compostela, Spain
Background: CCR5 antagonists exclusively act against R5-tropic HIV-1 variants. Therefore, tropism determination is required before maraviroc initiation. Herein, we evaluated the rate and characteristics of R5 carriers in a recent large set of HIV-1 patients.
Methods: All consecutive HIV-1 individuals tested for viral tropism since Jan-2008 up to Jan-2012 at our institution were analyzed. Viral tropism was determined on V3 sequences derived from plasma and PBMC samples using geno2phenoFPR=10%.
Results: A total of 2300 individuals were analysed, 239 (10.4%) infected with non-B subtypes. Overall, 25.8% were ARV-naive recently infected with HIV, 40.5% were chronic ARV-naive and 33.6% were ARV-experienced patients. Median viral load was 4.32 [3.45-4.92] log HIV-RNA copies/mL and median CD4 count was 397 [236-602] cells/mm3.
The overall prevalence of R5-viruses was 78%, higher in ARV-naive than ARV-experienced patients (82% vs. 71%, p< 0.001). There were no differences between ARV-naive recently- and chronically infected with HIV (83% vs. 80%, p>0.1). R5-viruses were more frequently found in patients with CD4>200 cells/mm3 than in those with ≤200 cells/mm3 either in the overall population (81% vs. 64%, p< 0.001), ARV-naive (83% vs. 67%, p< 0.001) or ARV-experienced patients (75% vs. 58%, p< 0.001). Figure 1 depicts R5 rate according to CD4 strata. All CD4 ranges over 200 cells/mm3 displayed similar R5 frequency, significantly higher than patients with CD4≤200 cells/mm3.
[Figure 1. R5-viruses rate according to CD4 strata]
Multivariate analysis (OR [CI95%], p) identified higher viral load (1.22 [1.07-01.39], 0.003) and CD4>200 cells/mm3 (2.92 [2.15-3.95], < 0.001) as predictors of R5 tropism, while a strong trend was observed for ARV-naive (1.33 [0.99-1.79], 0.057). In the subset of ARV-naive patients, CD4>200 cells/mm3 (2.66 [1.78-3.95], < 0.001) was the only predictor of R5 tropism.
Conclusions: R5-viruses are more frequent in ARV-naive than ARV-experienced HIV-1 patients. Individuals with CD4>200 cells/mm3 harbour the highest rate of R5-viruses (>80%), regardless treatment exposure.
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