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Updated: Jun 8, 2026
Prediction of HIV-1 Coreceptor Usage (Tropism) by Sequence Analysis using a Genotypic Approach
Published on: December 1, 2011
Performance of genotypic tropism testing in clinical practice using the enhanced sensitivity version of Trofile as
Valentina Svicher1, Roberta D'Arrigo, Claudia Alteri
1University of Rome Tor Vergata, Department of Experimental Medicine, Roma, Italy.
Objective:
The goal of the OSCAR programme is to evaluate the performances of genotypic HIV-1 tropism testing in clinical practice using the enhanced sensitivity version of Trofile (ESTA) as reference-assay.
Methods:
HIV-1 coreceptor-usage was assessed using plasma samples from 406 HIV-1 infected patients by ESTA and by gp120 V3 population-sequencing followed by Geno2pheno (set at a False Positive Rate [FPR] of 10% and 5%).
Results:
ESTA was successful in 365 (89.9%) samples indicating R5 in 254 (69.6%), and DM/X4 in 111 (30.4% of samples (104 [28.5%] DM and 7 [1.9%] X4). Genotypic-testing successfully assessed viral tropism for all 406 samples, including the 41 with undetermined result by ESTA. Genotypic-tropism testing at a FPR of 5% and 10% was 81.1% and 78.4% concordant with ESTA, respectively. Despite a sensitivity of 48.7% and 55.9% at a FPR of 5% and 10%, respectively, a high concordance (specificity: 95.3% for FPR of 5% and 88.2% for FPR of 10%) between genotypic-tropism testing and ESTA was reached in the detection of R5-tropic viruses.
Conclusion:
Our results are in line with other European studies, and support the routine use of genotypic tropism testing in clinical-settings for monitoring of HIV-1 infected patients candidate to or failing CCR5-antagonists.
