RELATION BETWEEN THE RISE IN PLASMA VIRAL LOAD AND THE PRESENCE OF ANTIVIRAL DRUGS RESISTANCE ASSOCIATED MUTATIONS.

M.GÓMEZ CARRILLO,; G.KIJAK,; S. PAMPURO,; H.SALOMÓN.-

Durban, South Africa

Conferencia; XIII INTERNATIONAL AIDS CONFERENCE,; 2000

International AIDS Society

Background: The rise in plasma viral load (PVL) can be associated to many factors, among them the lack of adherence and the selection of antiretroviral drugs-resistant viral variants. The aim of this study is to analyze the rolI of antiretroviral drug-resistance in patients showing therapeutic failure. Methods: Peripheral blood samples were taken from 1 4 patients who showed therapeutic failure (defined as a rise of 1 .0 Iog or more in PVL) and lived in Buenos Aires, Argentina. Proviral DNA was extracted from mononuclear cells, the regions of interest of the Viral Protease (VP) and Reverse Transcriptase (RT) were amplified by nested PCR and automatically sequenced (AB1 PRISM DNA, Perkin Elmer). The PVL was assessed by the b-DNA method (Chiron Co.). Results: Primary mutations in the RT region were found in 1 0 patients (71.4%). Seven of them (50%) had only AZT-resistance related mutations (mainly M41 L in 7 patients and T21 5Y in 6). Three indMduals (21 .4%) had mutations associated to resistance to both AZT and 3TC, and 4 patients had only secondary mutations (L214F and R211 K). In the VP region, resistance to saquinavir (mutations Li 01, M461, A71V, A71V and L9OM) was observed in 1 patient (7.1%) and cross-resistance to ritonavir and indinavir (mutations M461, 54V, L63P, V771 and V82A) in 1 patient (7.1%), while the rest of the patients only had secondary mutations (mainly L63P, V771, A71T, L101 and M461). Conclusions: These data suggest that the therapeutic failure is not always associated to resistance to antiretrovital drugs, as no mutations associated to resistance were detected in 28.6% of the patients