Prevalencia de resistencia primaria en pacientes con infección reciente por VIH-1 en Chile / Prevalence of primary antiretroviral resistance among HIV infected patients in Chile

ABSTRACT

Background: The main cause of virological failure during AIDS treatment is the resistance to antiretroviral medications (ARV). Aim: To search for mutations associated with ARV resistance in recently HIV-1 infected patients naïve to treatment, in Chile. Material and Methods: Patients over 18 years old with HIV-1 infection, naïve to antiretroviral drugs before the study were included. Patients with CD4 cell counts less than 200 cells/mm³, viral load below 2.000 copies/mL or any condition indicative of advanced AIDS were excluded. Criteria for diagnosis of recent infection (< 18 months) were a previous negative test for HIV antibodies or a history of an acute retroviral syndrome in the past 18 months. Resistance to drugs was analyzed using the TRUGENEtm HIV-1 assay from Bayer and the OpenGene DNA sequencing system. Results: Ninety nine percent of patients had at least one mutation, 27 percent had 4 or more mutations, but high level resistance to ARV was found only in 2.7 percent of cases. Point mutations for non nucleoside reverse transcriptase inhibitors (NNRTI) were detected in 4.1 percent of cases (K103N in 1 patient, V179D in 2 patients), for nucleoside reverse transcriptase inhibitors (NRTI) in 8.1 percent of cases (T215S in 1 patient, V118I in 4 patients, M41L in 1 patient) and for protease inhibitors (PI) in 1.3 percent of cases. All mutations detected in the protease gene were secondary. Of these, the most common were L63P/T (38 patients), L10I/V (27 patients) and V77I (26 patients). Resistance to two or more antiretroviral classes was not detected. Conclusions: This study supports that, by now, primary resistance has a low prevalence in Chile. Therefore, a genotyping test before starting antiretroviral therapy is not necessary.