Association between KIR genotypes and HLA-B alleles on viral load in Southern Brazilian individuals infected by HIV-1 subtypes B and C.

There is a great variety of HIV-1 subtypes circulating in Brazil, including subtype C, whose prevalence is on the rise, particularly in the southern region. Many host and viral genetic factors may be involved in this trend. We evaluated the influence of human leukocyte antigen (HLA) class I alleles and killer-cell immunoglobulin-like receptor (KIR) genotypes on viral set point and T-CD4(+) parameters in 84 treatment-naïve HIV-1-positive individuals. Frequency data in the infected group were compared to data of 548 healthy control subjects. Individuals with the KIR AA genotype had a higher viral load (VL) than individuals with the KIR Bx genotype. The HIV-1 group was subdivided into three subgroups according to HLA-B allele presence: those with protection to disease alleles (HLA-B(+)), accelerated disease progression alleles (HLA-B(-)), or neither (HLA-B(o)) were grouped. We observed a significant effect of the HLA-B allele presence on VL. The HLA-B(+) group had significantly lower VL than the HLA-B(-) group and trended toward a lower VL than the HLA-B(o) group. There were significant differences between groups expressing extreme VL values: KIR-AA+HLA-B(-) vs. KIR Bx+HLA-B(+) and KIR-AA+HLA-B(o)vs. KIR Bx+HLA-B(+). The relationship of KIR/HLA host genetics with slow HIV disease progression in southern Brazil may be useful for vaccine developers, epidemiologists, and clinicians.

Prevalence of transmitted HIV-1 antiretroviral resistance among patients initiating antiretroviral therapy in Brazil: a surveillance study using dried blood spots.

INTRODUCTION: In Brazil, the use of antiretrovirals is widespread: more than 260,000 individuals are currently undergoing treatment. We conducted a survey targeting antiretroviral-naïve individuals who were initiating antiretroviral therapy (ART) according to local guidelines. This survey covered five Brazilian regions. METHODS: The HIV Threshold Survey methodology (HIV-THS) of the World Health Organization was utilized, and subjects were selected from seven highly populated cities representative of all Brazilian macro-regions. Dried blood spots (DBS) were collected on SS903 collection cards and were transported by regular mail at room temperature to a single central laboratory for genotyping. RESULTS: We analysed samples from 329 individuals initiating highly active antiretroviral therapy (HAART), 39 (11.8%) of whom were harbouring transmitted drug resistance (TDR). The mean CD4+ T cell count was 253 cells/µL, and the mean viral load was 142,044 copies/mL. The regional prevalence of resistance was 17.0% in the Northeast, 12.8% in the Southeast, 10.6% in the Central region, 8.5% in the North and 8.5% in the South. The inhibitor-specific TDR prevalence was 6.9% for nucleoside reverse transcriptase inhibitors, 4.9% for non-nucleoside reverse transcriptase inhibitors and 3.9% for protease inhibitors; 3.6% of individuals presented resistance to more than one class of inhibitors. Overall, there were trends towards higher prevalences of subtype C towards the South and subtype F towards the North. Of the DBS samples collected, 9.3% failed to provide reliable results. DISCUSSION: We identified variable TDR prevalence, ranging from intermediate to high levels, among individuals in whom HIV disease progressed, thus implying that resistance testing before initiating ART could be effective in Brazil. Our results also indicate that the use of DBS might be especially valuable for providing access to testing in resource-limited and remote settings.

Genetic diversity in HIV-1 subtype C LTR from Brazil and Mozambique generates new transcription factor-binding sites.

The HIV-1 subtype C has been substituting the subtype B population in southern Brazil. This phenomenon has been previously described in other countries, suggesting that subtype C may possess greater fitness than other subtypes. The HIV-1 long-terminal repeat (LTR) is an important regulatory region critical for the viral life cycle. Sequence insertions immediately upstream of the viral enhancer are known as the most frequent naturally occurring length polimorphisms (MFNLP). Previous reports demonstrated that the MFNLP could lead to the duplication of transcription factor binding sites (TFBS) enhancing the activity of the HIV-1 subtype C LTR. Here, we amplified and sequenced the LTR obtained from proviral DNA samples collected from patients infected with subtype C from the Southern Region of Brazil (naïve or treatment failure) and Mozambique (only naïve). We confirm the presence of different types of insertions in the LTR sequences of both the countries leading to the creation of additional TFBS. In the Brazilian clinical samples, the frequency of the sequence insertion was significantly higher in subjects experiencing treatment failure than in antiretroviral naïve patients.

Virologic and immunologic effectiveness at 48 weeks of darunavir-ritonavir-based regimens in treatment-experienced persons living with HIV-1 infection in clinical practice: a multicenter Brazilian cohort.

INTRODUCTION: Published data addressing the effectiveness of darunavir-ritonavir (DRV/r)-based therapy for multiexperienced patients in developing countries are scarce. This study evaluated the 48-week virologic and immunologic effectiveness of salvage therapy based on DRV/r for the treatment of multidrug-experienced HIV-1-infected adults in Brazil. MATERIALS AND METHODS: A multicenter retrospective cohort study was carried out with multidrug-experienced adults who were on a failing antiretroviral therapy and started a DRV/r-based salvage therapy between 2008 and 2010. The primary effectiveness end point was the proportion of patients with virologic success (plasma HIV-1 RNA <50 copies/mL at week 48). RESULTS: At 48 weeks, 73% of the patients had HIV-RNA <50 copies/mL and a mean increase of 108 CD4 cells/mm(3). Higher baseline viral load, lower baseline CD4 count, younger age, and 3 or more DRV/r-associated resistance mutations were significantly predictive of virologic failure. Concomitant use of raltegravir was strongly associated with virologic success. CONCLUSION: The use of DRV/r-based regimens for salvage therapy is an effective strategy in the clinical care setting of a developing country.

Brazilian Network for HIV Drug Resistance Surveillance: a survey of individuals recently diagnosed with HIV.

Use of antiretrovirals is widespread in Brazil, where more than 200,000 individuals are under treatment. Although general prevalence of primary antiretroviral resistance in Brazil is low, systematic sampling in large metropolitan areas has not being performed.The HIV Threshold Survey methodology (HIV-THS, WHO) was utilized, targeting Brazil's four major regions and selecting the six most populated state capitals: Sao Paulo, Rio de Janeiro, Salvador, Porto Alegre, Brasilia and Belem. We were able to sequence samples from 210 individuals with recent HIV diagnosis, 17 of them (8.1%) carrying HIV isolates with primary antiretroviral resistance mutations. Five, nine and four isolates showed mutations related to resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs), respectively. Using HIV-THS, we could find an intermediate level of transmitted resistance (5% to 15%) in Belem/Brasilia, Sao Paulo and Rio de Janeiro. Lower level of transmitted resistance (<5%) were observed in the other areas. Despite the extensive antiretroviral exposure and high rates of virologic antiretroviral failure in Brazil, the general prevalence of primary resistance is still low. However, an intermediate level of primary resistance was found in the four major Brazilian cities, confirming the critical need to start larger sampling surveys to better define the risk factors associated with transmission of resistant HIV.

Perinatal HIV-1 transmission among low income women participants in the HIV/AIDS Control Program in Southern Brazil: a cohort study.

OBJECTIVE: To determine the rate and factors associated with perinatal transmission among women infected with HIV-1. DESIGN: Cohort study. SETTING: Centro Municipal de Atendimento em DST/AIDS is a major reference centre for HIV treatment in Porto Alegre city, southern Brazil. POPULATION: Pregnant and puerperal women infected with HIV-1. METHODS: Women were enrolled during pregnancy and seen monthly at the antenatal care centre. Those detected at delivery that presented at the centre within the first 10 days of postpartum were included. Maternal, obstetric and infant-related characteristics were ascertained and testing for CD4 cell count, HIV PCR/RNA assay, anti-HCV, HBSAg and syphilis were performed. Antiretrovirals and formula were provided free of charge following Brazilian guidelines. MAIN OUTCOME MEASURE: HIV-1 infection status in the infant. RESULTS: Perinatal transmission was assessed in 343 children (95% of the whole sample). Overall, the transmission rate was 3.2% (95% CI: 1.7-5.8%). Perinatal transmission rates increased with maternal viral load (>/=10,000 copies/mL; RR: 11.27; 95% CI: 1.38-92.23). In multivariate analyses, the only independent risk factor for perinatal transmission was the maternal viral load at baseline (OR = 2.72 per log increase in the number of copies; 95% CI: 1.17-6.50). CONCLUSION: Perinatal transmission rate was low among HIV-1 infected women in clinical care and on antiretroviral therapy despite poor socio-economic conditions. Viral load level was the only independent predictor of perinatal transmission. It is possible to prevent HIV-1 perinatal transmission in a developing country if we provide antiretrovirals and formula.