IDENTIFICATION OF HIV-1 SUBTYPES BY ENV-HMA AND GAG-HMA IN A COHORT OF ARGENTINE PERINATALLY INFECTED CHILDREN

P AULICINO,; M OVEJERO,; M BATALLA,; M GOMEZ CARRILLO,; M M AVILA,; L SEN

Barcelona, España

Conferencia; XIV INTERNATIONAL AIDS CONFERENCE; 2002

International AIDS Society

Background: In our laboratory, diagnosis of early HIV-1 infection in children born to infected mothers is done by nested multiplex PCR. The criterion used for the diagnosis is the finding of at least one of 2 viral genes (gag or env) in 2 consecutive blood samples positive for â-actin (control). Since 1996 we have detected 286 positive and 2 false negative cases out of 1513 studied. In the latter, due to persistent clinical symptoms, HIV-1 infection was confirmed by a high plasma viral load. Of the 286 positive cases, only 13 did not amplify one of the two viral genes (the same one in two consecutive samples). Aim: To initially characterize the HIV-1 subtype in the 13 positive samples for only one gene (12 gag+/env- ; 1 gag-/env+) and the 2 false negative cases by means of the Heteroduplex Mobility Assay (HMA) for 460bp gag and 700bp env sequences. Results: Only 3 of the 13 PCR gag+/env- or gag-/env+ cases amplified both 460bp gag and 700bp env fragments necessary for HMA subtyping, resulting both in subtype F. Another 8 only amplified 460bp gag fragment, which resulted in subtype F for all of them. The remaining 2 could not be amplified at all. Surprisingly, the two false negative cases could be subtyped both in env and gag, resulting one of them to be gag F/env F and the other one gag A/env A. Conclusions: According to our preliminary results, all but one of the HIV+ selected cases belong to the F subtype both in env and gag. However, a recent report indicates that 6 out of 6 envHMA subtype F Argentinean strains were actually BF recombinants upon full genome analysis and that the nonrecombinant F subtype is rare. Based on these facts, the  recombinants rather than pure F and further investigation is being carried out to address this matter. The only A subtype (not found in Argentina till present) belongs to a girl coming from Peru, where this subtype has been documented.