Efficiencies of four versions of the AMPLICOR HIV-1 MONITOR test for quantification of different subtypes of human immunodeficiency virus type 1

Three versions of a commercial human immunodeficiency virus (HIV) type I (H IV-1) load test (the AMPLICOR HIV-1 MONITOR Test versions 1.0, 1.0+, and 1. 5; Roche Diagnostics, Branchburg, N.J.) were evaluated for their ability to detect and quantify HIV-I RNA of different genetic subtypes. Plasma sample s from 96 patients infected with various subtypes of HIV-1 (55 patients inf ected with subtype A, 9 with subtype B, 21 with subtype C, 2 with subtype D , 7 with subtype E, and 2 with subtype G) and cultured virus from 29 HIV-I reference strains (3 of subtype A, 6 of subtype B, 5 of subtype C, 3 of sub type D, 8 of subtype E, 3 of subtype F, and I of subtype G) were tested. De tection of subtypes A and E was significantly improved,vith versions 1.0+ a nd 1.5 compared to that with version 1.0, whereas detection of subtypes B, C, D, and G was equivalent with the three versions. Versions 1.0, 1.0+, and 1.5 detected 65, 98, and 100% of the subtype A-infected samples from patie nts, respectively, and 71, 100, and 100% of the subtype E-infected samples from patients, respectively. Version 1.5 yielded a significant increase in viral load for samples infected with subtypes A and E (greater than 1 log(1 0) HIV RNA copies/ml). For samples infected with subtype B, C, and D and te sted with version 1.5, only a slight increase in viral load was observed (< 0.5 log,,). We also evaluated a prototype automated version of the test tha t uses the same PCR primers as version 1.5. The results with the prototype automated test were highly correlated with those of the version 1.5 test fo r all subtypes, but were lower overall. The AMPLICOR HIV-1 MONITOR Test, ve rsion 1.5, yielded accurate measurement of the HN load for all HIV-1 subtyp es tested, which should allow the test to be used to assess disease prognos is anti response to antiretroviral treatment in patients infected with a gr oup M HIV-1 subtype.