AEGiS-14IAC: HIV-1 genetic diversity: impact on the performance of three commercial viral load assays.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

HIV-1 genetic diversity: impact on the performance of three commercial viral load assays.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. B10195)

Swanson P, de Mendoza C, Bodelle P, Yamaguchi J, Golden A, Brennan C, Soriano V, Devare SG, Schochetman G, Hackett J
Abbott Laboratories, Abbott Park, IL, United States

BACKGROUND: The evolution and ever-changing distribution of HIV-1 strains challenge the performance of nucleic acid-based tests. Reliable patient monitoring requires that viral load assays have the ability to detect and accurately quantify genetically diverse HIV-1. In this study, three commercially available quantitative tests were evaluated on a plasma panel of group M, group O and recombinant viruses.

METHODS: A panel of 98 HIV seropositive plasma specimens was collected in Cameroon, South Africa and Brazil. HIV RNA concentrations were compared using three ultrasensitive viral load assays: LCx HIV RNA Quantitative (LCx é «), AMPLICOR HIV-1 MONITOR version 1.5 (v1.5) and Quantiplex HIV-1 RNA version 3.0 (bDNA). The gag p24, pol integrase, and env gp41 region sequences of each sample were characterized to assign group/subtype and to assess genetic diversity at primer/probe binding sites.

RESULTS: Based on phylogenetic analysis, the population included group M subtypes A, B, C, D, F, G, and mosaics (CRF01-AE, CRF02-AG, G/A, F/B, and H/A) as well as group O. For group M samples quantitated within the dynamic range of each assay, 95.4% (83/87) were within 1 log₁₀ RNA copies/ml between LCx and v1.5, 98.9% (91/92) between LCx and bDNA, and 94.2% (82/87) between v1.5 and bDNA. Relative to LCx and bDNA, v1.5 underquantified 2 subtype A/G mosaics by more than 1 log₁₀ RNA copies/ml and failed to quantitate 2 additional A/G mosaics. Relative to v1.5 and bDNA, LCx underquantified 1 G/A mosaic sample by more than 1 log₁₀ RNA copies/ml. The two group O plasmas were only quantified by the LCx assay.

CONCLUSIONS: Overall, there was good correlation for group M-infected plasma specimens between all three viral load assays. However, only the LCx assay quantified the group O samples. Of the tests evaluated, performance of the LCx was the most subtype- and group-independent.

Keywords: AEGIS, Viral Load, HIV-1, HIV Infections, Variation (Genetics), HIV Seropositivity, Brazil, Cameroon, South Africa, Human, genetics

020707
B10195