The Virological and Immunological Characteristics of the HIV-1-Infected Population in Brazil: From Initial Diagnosis to Impact of Antiretroviral Use.

BACKGROUND: Immunological and virological status of HIV-infected individuals entering the Brazilian public system over time was analyzed. We evaluated the impact of ART on virological, immunological and antiretroviral resistance over time. METHODS: CD4+ T cell counts, viral loads and genotypes from patients over 13 years old from 2001-2011 were analyzed according to demographic data. We compared groups using parametric t-tests and linear regression analysis in the R statistical software language. RESULTS: Mean baseline CD4+ T cell counts varied from 348 (2003) to 389 (2009) and was higher among women (p = 1.1 x 10(-8)), lower in older patients (p< 1 x 10(-8)) and lower in less developed regions (p = 1.864 x 10(-5)). Percentage of treated patients with undetectable viral loads increased linearly from 46% (2001) to 77% (2011), was lower among women (p = 2.851 x 10(-6)), younger ages (p = 1 x 10(-3)), and in less developed regions (p = 1.782 x 10(-4)). NRTI acquired resistance was 86% in 2001-3 and decreased over time. NNRTI resistance increased from 2001-3(50%) to 2006-9 (60%), PI resistance decreased from 2001-3 (60%) to 2009 (40%), and 3-class resistance was stable over time around 25%. Subtype prevalence comprised B (75.3%), B/F recombinants (12.2%), C (5.7%), F (5.3%) and B/C recombinants (1.5%), with regional variations. Three-class resistance was 26.5% among Bs, 22.4% among Fs and 17.2% among Cs. CONCLUSIONS: HIV diagnosis occurs late, especially among elderly Brazilians. Younger individuals need special attention due to poor virological response to treatment. Antiretroviral Resistance profile is subtype related.

HIV type 1 antiretroviral resistance mutations in subtypes B, C, and F in the City of São Paulo, Brazil.

In Brazil, where three distinct HIV-1 subtypes (B, F, and C) cocirculate, a significant portion of the HIV-infected population has been exposed to antiretroviral drugs. This study analyzes the antiretroviral resistance profiles of HIV-1-infected individuals failing antiretroviral therapy. Genotypic resistance profiles of 2474 patients presenting virologic failure to antiretroviral therapy in the city of São Paulo, Brazil, were generated and analyzed. Resistance mutations to protease inhibitors and nucleoside reverse transcriptase inhibitors were less common in subtype C viruses, whereas nonnucleoside reverse transcriptase inhibitor resistance mutations were less common in subtype F viruses. The thymidine analog mutation pathway known as pathway 1 was more prevalent in subtype B viruses than in subtype C viruses, whereas pathway 2 was more prevalent in subtype C viruses. Selected resistance mutations varied according to subtype for all three classes of antiretrovirals. We describe two distinct pathways of nonnucleoside reverse transcriptase inhibitor resistance (to nevirapine and efavirenz). Although cross-resistance to etravirine should occur more frequently among individuals failing nevirapine treatment, the prevalence of cross-resistance to etravirine, darunavir, and tipranavir was found to be low. We found that increases in the number of resistance mutations will be related to increases in the viral load. Special attention should be given to resistance profiles in non-B subtype viruses. The accumulation of knowledge regarding such profiles in the developing world is desirable.