Molecular and Phylogenetic Analysis of HIV-1 Subtype C in Bahia State, Northeastern Brazil.

HIV-1 subtype C is associated with more than half of infections in southern Brazil and has been increasing in other regions of the country. In a previous study carried out in northeastern Brazil, we found a prevalence of 4.1% of subtype C. This work investigates the origin of subtype C in the state of Bahia based on five new viral sequences. The phylogenetic analysis showed that subtype C viruses found in Bahia descend from the main lineage that circulates in other Brazilian regions.

Tracing the relationship among HIV-1 sub-subtype F1 strains: a phylodynamic perspective.

BACKGROUND: The human immunodeficiency virus type 1, F1 sub-subtype (HIV-1 F1) circulates in three continents: Africa, Europe, and South America. In Brazil, this sub-subtype co-circulates with subtypes B and C and several recombinant forms, mainly BF1 variants. OBJECTIVES: This study aimed to reconstruct the dynamic history of HIV-1 F1 in Brazil. METHODS: HIV-1 near full-length genome and pol gene nucleotide sequences available in public databases were assembled in two datasets (POL671 and NFLG53) to cover the largest number of F1 sub-subtype sequences. Phylodynamic and temporal analyses were performed. FINDINGS: Two main strains of the F1 sub-subtype are circulating worldwide. The first (F1.I) was found among Brazilian samples (75%) and the second (F1.II) among Romanian (62%) and other European and African isolates. The F1 subtype epidemic in Brazil originated from a single entry into the country around 1970. This ancestral sample is related to samples isolated in European countries (France, Finland, and Belgium), which are possibly of African origin. Moreover, further migration (1998 CI: 1994-2003) of strains from Brazil to Europe (Spain and the UK) was observed. Interestingly, all different recombinant BF patterns found, even those from outside Brazil, present the same F1 lineage (F1.I) as an ancestor, which could be related to the acquisition of adaptive advantages for the recombinant progenies. MAIN CONCLUSIONS: These findings are important for the understanding of the origin and dynamics of the F1 sub-subtype and a consequent better and greater understanding of the HIV-1 F1 and BF epidemic that still spreads from Brazil to other countries.

Identification of a new circulating recombinant form of human immunodeficiency virus type 1, CRF124_cpx involving subtypes A, G, H, and CRF27_cpx in Angola.

Angola, located in Central Africa, has around 320,000 (270,000-380,000) people living with human immunodeficiency virus (HIV)/AIDS, equivalent to 1% of the country's population at the end of 2021. A previous study conducted in 2012, using Angolan samples collected between 2008 and 2010 revealed a high prevalence of HIV-1 recombinants, around 42% of sequences, with 21% showing the same UH profile in partial pol region which were grouped into a monophyletic cluster with high bootstrap support. Thus, the objective of the present work was to obtain complete genomes of those sequences and characterize them, aiming at a description of a new circulating recombinant form (CRF). Whole blood from nine HIV-1 UH pol-infected individuals had their genomic DNA extracted, and nested PCR was used to amplify seven overlapping fragments targeting the full-length HIV-1 genome. The final classification was based on maximum likelihood trees, and recombination analyses were performed using a bootscan from the Simplot program. BLAST and Los Alamos Database inspections were used to search other similar H-like pol sequences. Complete genome amplification was possible for three samples, partial genomes were obtained for the other three, and only pol was available for the remaining three sequences. Bootscan analysis of the two whole-genome and three partial genome sequences retrieved from people living with HIV/AIDS (PLHIVA) without epidemiological linkage showed the same complex recombination profile involving HIV-1 subtypes A/G/H/CRF27_cpx, with a total of six recombinant breakpoints, aiming to classify a new HIV-1 CRF124_cpx. We found no other full-length HIV-1 genomes with the same mosaic profile; however, we identified 33 partial pol sequences, mainly sampled from Angola between 2001 to 2019, with the same H-like profile. Bayesian analysis of H and H-like pol sequences indicates that CRF124_cpx probably originated in Angola at mid-1970s, indicating that this CRF has been circulating in the country for a long time. In summary, our study describes a new CRF circulating principally in Angola and highlights the importance of continuing molecular surveillance studies, especially in countries with high molecular diversity of HIV.

Molecular Epidemiology of HIV-1 among Prisoners in Central Brazil and Evidence of Transmission Clusters.

Higher rates of human immunodeficiency virus (HIV) infection have been detected in prisoners when compared with the general population, but research into HIV molecular epidemiology and its transmission network has been lacking among them. Thus, this study aimed to verify potential HIV molecular transmission networks among prisoners. In addition, we aimed to describe the mutations related to antiretroviral resistance in these isolates. Thus, we conducted a cross-sectional survey from 2013 to 2018 in prisons in Central-Western Brazil, and the final sampling composed of 84 prisoners. Proviral DNA was extracted from each whole blood sample followed by amplification of the partial polymerase gene and sequencing. Forty-nine sequences (58.3%) were classified as subtype B, followed by C (14.3%), D, and F1 (2.4% each). A complex and dynamic HIV-1 epidemic is observed in the prisons, as 25% of the sequences were recombinant forms. We detected 15 HIV transmission clusters composed of at least two sequences, that included not only prisoners but also individuals from the general population from the same State with a variety of risk behaviors. Thirty-two percent (32.0%) of treatment-experienced prisoners had at least one drug resistance mutation (DRM), while transmitted DRMs were found in 5.9% of the prisoners. We highlight the urgent need for routine surveillance of HIV-1 infection including resistance genotypic tests considering the high disease burden, risky behaviors inside prisons, and the dynamic relationship of prisoners with the outside community.

HIV-1 Diversity and Drug Resistance in Treatment-Naïve Children and Adolescents from Rio de Janeiro, Brazil.

The human immunodeficiency virus type 1 (HIV-1) can be transmitted via parenteral, sexual, or vertical exposure routes. The number of HIV-1 cases detected yearly in children and adolescents in Brazil did not decrease over the last decade, representing ~5% of total cases described in the country. In recent years, the HIV-1 diversity and the prevalence of transmitted drug resistance mutations (TDRM) are moving toward a marked increase. In this study, we retrospectively evaluated the diversity of HIV-1 subtypes and the TDRM prevalence in 135 treatment-naïve HIV-1 vertically infected children and adolescents born in between 1993 and 2012. These children were assessed in either 2001-2007 or 2008-2012 when they were 0 to 17 years old. The individuals assessed in 2001-2007 (n = 38) had median CD4+ T cell counts of 1218 cells/mm3 (IQR: 738-2.084) and median HIV-1 plasma viral load of 4.18 log10 copies/mL (IQR: 3.88-4.08). The individuals (n = 97) evaluated in 2008-2012 showed median CD4+ T cell counts of 898.5 cells/mm3 (IQR: 591.3-1.821) and median HIV-1 plasma viral load of 4.69 log10 copies/mL (IQR: 4.26-5.33). A steady decrease in the median CD4 T+ cell counts was observed with age progression, as expected. The majority HIV-1 pol sequences (87%) were classified as pure HIV-1 subtypes (77% subtype B, 9% subtype F1 and 1.5% subtype C), while 13% of sequences were classified as recombinants (CRF45_cpx, n = 4; CRF28/29_BF1, n = 2; CRF02_AG, n = 1; CRF40_BF1, n = 1, CRF99_BF1, n = 1, URF_BF1, n = 8). The overall prevalence of TDRM was 14% (19/135), conferring resistance to the nucleoside reverse transcriptase inhibitors (NRTI, 13/135-9.6%), non-nucleoside reverse transcriptase inhibitors (NNRTI, 8/135-5.9%), and protease inhibitors (PI, 2/135-1.5%). The main TDRM observed for NNRTI was the K103N (n = 8), while the mutations T215I/Y/D/E (n = 7) and M184V (n = 4) were the main TDRM for NRTI. Only two TDRM were observed for PI in one individual each (M46I and V82A). Most TDRM were found in the HIV-1 subtype B (84%) sequences. This study reveals an HIV-1 epidemic with high diversity and moderate prevalence of TDRM in the pediatric population of Rio de Janeiro, indicating the existence of possible problems in the clinical management of prophylactic therapy to prevent mother-to-child transmission and future treatment options for the affected children.

Increased biomarkers of cardiovascular risk in HIV-1 viremic controllers and low persistent inflammation in elite controllers and art-suppressed individuals.

HIV controllers (HICs) are models of HIV functional cure, although some studies have shown persistent inflammation and increased rates of atherosclerosis in HICs. Since immune activation/inflammation contributes to the pathogenesis of cardiovascular diseases (CVD), we evaluated clinical data and inflammation markers in HIV-1 viremic controllers (VC), elite controllers (EC), and control groups (HIV positive individuals with virological suppression by antiretroviral therapy-cART; HIV negative individuals-HIVneg) to assess whether they presented elevated levels of inflammation markers also associated with CVD. We observed the highest frequencies of activated CD8+ T cells in VCs, while EC and cART groups presented similar but slightly altered frequencies of this marker when compared to the HIVneg group. Regarding platelet activation, both HICs groups presented higher expression of P-selectin in platelets when compared to control groups. Monocyte subset analyses revealed lower frequencies of classical monocytes and increased frequencies of non-classical and intermediate monocytes among cART individuals and in EC when compared to HIV negative individuals, but none of the differences were significant. For VC, however, significant decreases in frequencies of classical monocytes and increases in the frequency of intermediate monocytes were observed in comparison to HIV negative individuals. The frequency of monocytes expressing tissue factor was similar among the groups on all subsets. In terms of plasma markers, VC had higher levels of many inflammatory markers, while EC had higher levels of VCAM-1 and ICAM-1 compared to control groups. Our data showed that VCs display increased levels of inflammation markers that have been associated with CVD risk. Meanwhile, ECs show signals of lower but persistent inflammation, comparable to the cART group, indicating the potential benefits of alternative therapies to decrease inflammation in this group.

Dissemination Dynamics of HIV-1 Subtype B Pandemic and Non-pandemic Lineages Circulating in Amazonas, Brazil.

The HIV-1 epidemic in the Amazonas state, as in most of Brazil, is dominated by subtype B. The state, nonetheless, is singular for its significant co-circulation of the variants BCAR, which can mostly be found in the Caribbean region, and BPAN, a clade that emerged in the United States and aggregates almost the totality of subtype B infections world-wide. The Amazonian HIV-1 epidemic provides a unique scenario to compare the epidemic potential of BPAN and BCAR clades spreading in the same population. To reconstruct the spatiotemporal dynamic and demographic history of both subtype B lineages circulating in Amazonas, we analyzed 1,272 HIV-1 pol sequences sampled in that state between 2009 and 2018. Our phylogeographic analyses revealed that while most BCAR infections resulted from a single successful founder event that took place in the Amazonas state around the late 1970s, most BPAN infections resulted from the expansion of multiple clusters seeded in the state since the late 1980s. Our data support the existence of at least four large clusters of the pandemic form in Amazonas, two of them nested in Brazil's largest known subtype B cluster (BBR-I), and two others resulting from new introductions detected here. The reconstruction of the demographic history of the most prevalent BPAN (n = 4) and BCAR (n = 1) clades identified in Amazonas revealed that all clades displayed a continuous expansion [effective reproductive number (R e) > 1] until most recent times. During the period of co-circulation from the late 1990s onward, the Re of Amazonian BPAN and BCAR clusters behaved quite alike, fluctuating between 2.0 and 3.0. These findings support that the BCAR and BPAN variants circulating in the Brazilian state of Amazonas displayed different evolutionary histories, but similar epidemic trajectories and transmissibility over the last two decades, which is consistent with the notion that both subtype B variants display comparable epidemic potential. Our findings also revealed that despite significant advances in the treatment of HIV infections in the Amazonas state, BCAR and BPAN variants continue to expand and show no signs of the epidemic stabilization observed in other parts of the country.

Tracing the relationship among HIV-1 sub-subtype F1 strains: a phylodynamic perspective

BACKGROUND The human immunodeficiency virus type 1, F1 sub-subtype (HIV-1 F1) circulates in three continents: Africa, Europe, and South America. In Brazil, this sub-subtype co-circulates with subtypes B and C and several recombinant forms, mainly BF1 variants. OBJECTIVES This study aimed to reconstruct the dynamic history of HIV-1 F1 in Brazil. METHODS HIV-1 near full-length genome and pol gene nucleotide sequences available in public databases were assembled in two datasets (POL671 and NFLG53) to cover the largest number of F1 sub-subtype sequences. Phylodynamic and temporal analyses were performed. FINDINGS Two main strains of the F1 sub-subtype are circulating worldwide. The first (F1.I) was found among Brazilian samples (75%) and the second (F1.II) among Romanian (62%) and other European and African isolates. The F1 subtype epidemic in Brazil originated from a single entry into the country around 1970. This ancestral sample is related to samples isolated in European countries (France, Finland, and Belgium), which are possibly of African origin. Moreover, further migration (1998 CI: 1994-2003) of strains from Brazil to Europe (Spain and the UK) was observed. Interestingly, all different recombinant BF patterns found, even those from outside Brazil, present the same F1 lineage (F1.I) as an ancestor, which could be related to the acquisition of adaptive advantages for the recombinant progenies. MAIN CONCLUSIONS These findings are important for the understanding of the origin and dynamics of the F1 sub-subtype and a consequent better and greater understanding of the HIV-1 F1 and BF epidemic that still spreads from Brazil to other countries.

High Detection Rate of HIV Drug Resistance Mutations among Patients Who Fail Combined Antiretroviral Therapy in Manaus, Brazil.

Virologic failure may occur because of poor treatment adherence and/or viral drug resistance mutations (DRM). In Brazil, the northern region exhibits the worst epidemiological scenarios for the human immunodeficiency virus (HIV). Thus, this study is aimed at investigating the genetic diversity of HIV-1 and DRM in Manaus. The cross-sectional study included people living with HIV on combined antiretroviral therapy and who had experienced virological failure during 2018-2019. Sequencing of the protease/reverse transcriptase (PR/RT) and C2V3 of the viral envelope gp120 (Env) regions was analyzed to determine subtypes/variants of HIV-1, DRMs, and tropism. Ninety-two individuals were analyzed in the study. Approximately 72% of them were male and 74% self-declared as heterosexual. Phylogenetic inference (PR/RT-Env) showed that most sequences were B subtype, followed by BF1 or BC mosaic genomes and few F1 and C sequences. Among the variants of subtype B at PR/RT, 84.3% were pandemic (B PAN), and 15.7% were Caribbean (B CAR). The DRMs most frequent were M184I/V (82.9%) for nucleoside reverse transcriptase inhibitors (NRTI), K103N/S (63.4%) for nonnucleoside reverse transcriptase inhibitor (NNRTI), and V82A/L/M (7.3%) for protease inhibitors (PI). DRM analysis depicted high levels of resistance for lamivudine and efavirenz in over 82.9% of individuals; although, low (7.7%) cross-resistance to etravirine was observed. A low level of resistance to protease inhibitors was found and included patients that take atazanavir/ritonavir (16.6%) and lopinavir (11.1%), which confirms that these antiretrovirals can be used-for most individuals. The thymidine analog mutations-2 (TAM-2) resistance pathway was higher in B CAR than in B PAN. Similar results from other Brazilian studies regarding HIV drug resistance were observed; however, we underscore a need for additional studies regarding subtype B CAR variants. Molecular epidemiology studies are an important tool for monitoring the prevalence of HIV drug resistance and can influence the public health policies.

A case report of HIV-1 superinfection in an HIV controller leading to loss of viremia control: a retrospective of 10 years of follow-up.

BACKGROUND: HIV controllers (HICs) are a rare group of HIV-1-infected individuals able to naturally control viral replication. Several studies have identified the occurrence of HIV dual infections in seropositive individuals leading to disease progression. In HICs, however, dual infections with divergent outcomes in pathogenesis have been described. CASE PRESENTATION: Here, we present a case report of a HIC diagnosed in late 1999 who displayed stable CD4+ T cell levels and low plasmatic viral load across 12 years of follow-up. In early 2013, the patient started to present an increase in viral load, reaching a peak of 10,000 copies/ml in early 2014, followed by an oscillation of viremia at moderate levels in the following years. The genetic diversity of env proviral quasispecies from peripheral blood mononuclear cells (PBMCs) was studied by single genome amplification (SGA) at six timepoints across 2009-2017. Phylogenetic analyses of env sequences from 2009 and 2010 samples showed the presence of a single subtype B variant (called B1). Analyses of sequences from 2011 and after revealed an additional subtype B variant (called B2) and a subsequent dominance shift in the proviral quasispecies frequencies, with the B2 variant becoming the most frequent from 2014 onwards. Latent syphilis related to unprotected sexual intercourse was diagnosed a year before the first detection of B2, evidencing risk behavior and supporting the superinfection hypothesis. Immunologic analyses revealed an increase in CD8+ and CD4+ T cell immune activation following viremia increase and minor T cell subset alterations during follow-up. HIV-specific T cell responses remained low throughout the follow-up period. CONCLUSIONS: Altogether, these results show that loss of viremia control in the HIC was associated with superinfection. These data alert to the negative consequences of reinfection on HIV pathogenesis, even in patients with a long history of viremia control and an absence of disease progression, reinforcing the need for continued use of adequate prevention strategies.

HIV-1 Molecular Epidemiology, Transmission Clusters and Transmitted Drug Resistance Mutations in Central Brazil.

We aimed to characterize HIV-1 molecular epidemiology and transmission clusters among heterosexual (HET) and men who have sex with men (MSM) individuals, as well as transmitted drug resistance mutations (TDRM) in Central-Western Brazil. This cross-sectional survey was conducted among 190 antiretroviral naïve HIV-1 infected individuals. Proviral DNA was extracted, and nested PCR amplified partial polymerase gene (PR/RT). After sequencing, subtypes were assigned, and the sequences were analyzed for the occurrence of possible transmission networks. Calibrated Population Resistance (CPR) tool from Stanford HIV Database was used to investigate the presence of TDRM. Among 150 individuals whose samples were successfully sequenced, the most prevalent HIV-1 subtype was B, followed by recombinant forms. The occurrence of twenty transmission clusters composed by at least two sequences was verified, suggesting the existence of transmission clusters among individuals from the same or distinct sexual orientations. Intermediate level of TDRM (12%) was found in the study population, and almost half of the subjects with TDRM had more than one resistance mutation. No correlations between sexual orientation and the presence of TDRM, HIV-1 subtypes/recombinants forms were verified. Taken together, the necessity of the continuous monitoring of the TDRM to verify the importance of pre-genotyping and to delineate future strategies in primary antiretroviral therapy. Likewise, the knowledge of the HIV-1 transmission networks in Brazil would allow the implementation of effective HIV-1 prevention strategies in local settings.

Reduction of HIV-1 Reservoir Size and Diversity After 1 Year of cART Among Brazilian Individuals Starting Treatment During Early Stages of Acute Infection.

The aim of early combined antiretroviral therapy (cART) of HIV is to limit the seeding of the viral reservoir during the initial phase of infection and, consequently, decrease intrahost viral diversity. Here, we assessed the effect of early cART on size and complexity of the proviral reservoir. Peripheral blood mononuclear cell (PBMC) and plasma samples were obtained from ten HIV-infected Brazilian individuals diagnosed at the acute phase of infection, before (PREART) and 12 months (M12ART) after suppressive cART. HIV proviral reservoir size was determined by quantitative real-time PCR; intrahost viral diversity of the env C2-V3 region was assessed by single genome amplification or next-generation sequencing in PBMC and plasma, respectively. Mean nucleotide diversity (π) and normalized Shannon entropy (HSN) were used to infer the complexity of the viral population. Compared to PREART, M12ART saw an immunological recovery with a gain of ∼200 CD4+ T cells (P = 0.008) and a normalization of the CD4/CD8 ratio [1.0 (IQR: 0.88-1.18), P = 0.016], as well as a significant decrease in HIV-1 RNA (∼4 log, P = 0.004) and DNA (∼1 log, P = 0.002) levels. The median time to achieve viral suppression was 3 months (IQR: 2.8-5.8 months). The high intermixing between sequences from both visits suggests that the HIV-1 DNA reservoir remained remarkably stable under cART. After 1 year of cART, there was a minor reduction in proviral π (PreART = 0.20 vs. M12ART = 0.10; P = 0.156) but a significant decrease in HSN (PreART = 0.41 vs. M12ART = 0.25; P = 0.019). We found no correlation between π or HSN at PreART and the rate of HIV DNA decay, T CD4+ counts, or CD4/CD8 ratio at M12ART. Based on a small cohort of Brazilian infected individuals under early cART and analyses of the env region, 1 year of follow-up suggested a reservoir size reduction, allowed a significant decrease of HIV-1 complexity, and achieved immunological restoration regardless of the initial HIV-1 plasma viral load, CD4+ T cell counts, or HIV-1 subtype. However, further studies in the Brazilian setting aiming a longer follow-up and larger cohort are required in this field.

Reduction of inflammation and T cell activation after 6 months of cART initiation during acute, but not in early chronic HIV-1 infection.

OBJECTIVES: To investigate the impact of early combined antiretroviral therapy (cART) on inflammation biomarkers and immune activation during acute and early chronic HIV-1 infection. METHODS: We included 12 acute (AHI), 11 early chronic (EcHI), and 18 late chronic HIV-1-infected (LcHI) individuals who were treated with cART and 18 HIV-1-uninfected (HIV-neg) individuals. Plasmatic levels of inflammation biomarkers, CD8+CD38+HLA-DR+ T cell frequencies, CD4 T cell counts, CD4/CD8 ratio, total HIV-1 DNA and plasmatic viral load were evaluated. Mann-Whitney test, Pearson and Spearman correlation, and linear regression models were used for statistical analyses. RESULTS: IP-10, IL-18, and sCD163 were significantly elevated at pre-ART in the AHI and EcHI groups, showing a significant reduction after 6 months of cART in the AHI group, achieving similar levels to the HIV-neg group. For the EcHI group, the IP-10 and sCD163 levels were also significantly reduced on M6-ART; however, IP-10 levels remained higher than in the HIV-neg group, and no significant reduction of IL-18 levels was observed. The CD8+ T cell activation levels were elevated in the AHI and EcHI groups at pre-ART and showed a significant reduction on M6-ART, but they were similar to levels seen for HIV-neg only after 12 months of cART. At pre-ART, IP-10 levels but not IL-18 levels were positively correlated with HIV-1 viral load in the AHI group. CONCLUSIONS: Early initiation of cART in HIV infection can reduce systemic inflammation, but the earlier normalization of the inflammation markers was only observed when cART was initiated in the acute phase of infection. A slower dynamic of reduction was observed for CD8+ T cell activation.

Next-generation sequencing analyses of the emergence and maintenance of mutations in CTL epitopes in HIV controllers with differential viremia control.

BACKGROUND: Despite the low level of viral replication in HIV controllers (HICs), studies have reported viral mutations related to escape from cytotoxic T-lymphocyte (CTL) response in HIV-1 plasma sequences. Thus, evaluating the dynamics of the emergence of CTL-escape mutants in HICs reservoirs is important for understanding viremia control. To analyze the HIV-1 mutational profile and dynamics of CTL-escape mutants in HICs, we selected 11 long-term non-progressor individuals and divided them into the following groups: (1) viremic controllers (VCs; n = 5) and (2) elite controllers (ECs; n = 6). For each individual, we used HIV-1 proviral DNA from PBMCs related to earliest (VE) and latest (VL) visits to obtain gag and nef sequences using the Illumina HiSeq system. The consensus of each mapped gene was used to assess viral divergence, and next-generation sequencing data were employed to identify SNPs and variations within and flanking CTL epitopes. RESULTS: Divergence analysis showed higher values for nef compared to gag among the HICs. EC and VC groups showed similar divergence rates for both genes. Analysis of the number of SNPs showed that VCs present more variability in both genes. Synonymous/non-synonymous mutation ratios were < 1 for gag among ECs and for nef among ECs and VCs, exhibiting a predominance of non-synonymous mutations. Such mutations were observed in regions encoding CTL-restricted epitopes in all individuals. All ECs presented non-synonymous mutations in CTL epitopes but generally at low frequency (< 1%); all VCs showed a high number of mutations, with significant frequency changes between VE and VL visits. A higher frequency of internal mutations was observed for gag epitopes, with significant changes across visits compared to Nef epitopes, indicating a pattern associated with differential genetic pressure. CONCLUSIONS: The high genetic conservation of HIV-1 gag and nef among ECs indicates that the higher level of viremia control restricts the evolution of both genes. Although viral replication levels in HICs are low or undetectable, all individuals exhibited CTL epitope mutations in proviral gag and nef variants, indicating that potential CTL escape mutants are present in HIC reservoirs and that situations leading to a disequilibrium of the host-virus relationship can result in the spread of CTL-escape variants.

Potential overestimation of HIV-1 sub-subtype F1 circulation in Rio de Janeiro, Brazil.

In Brazil, detection of the HIV-1 sub-subtype F1 has decreased with a simultaneous increase in detection of the recombinant FB and FC forms. In previous HIV-1 env molecular epidemiology studies in Rio de Janeiro, 11.4% of the detected sequences were of the F1 sub-subtype. With the goal of re-estimating the prevalence of the HIV-1 F1 sub-subtype, we performed extended analyses of these samples by examining five genomic regions, resulting in 3.3% being confirmed as F1. Moreover, genomic analysis of 11 of the 21 samples identified as F1 confirmed that nine were F1 and two were BF1. Considering the number of samples assayed, the prevalence of F1 was quite low, which supports the use of different genomic regions for the assessment of HIV-1 classification in countries where several subtypes and recombinant forms co-circulate.

Characterization of HIV-1 CRF90_BF1 and putative novel CRFs_BF1 in Central West, North and Northeast Brazilian regions.

The Brazilian AIDS epidemic has been characterized by an increasing rate of BF1 recombinants and so far eight circulating recombinant forms/CRFs_BF1 have been described countrywide. In this study, pol sequences (protease/PR, reverse transcriptase/RT) of 87 BF1 mosaic isolates identified among 828 patients living in six Brazilian States from three geographic regions (Central West, North, Northeast) were analyzed. Phylogenetic and bootscan analyses were performed to investigate the evolutionary relationship and mosaic structure of BF1 isolates. Those analyses showed that 20.7% of mosaics (18 out of 87) were CRFs-like isolates, mostly represented by CRF28/CRF29_BF-like viruses (14 out of 18). We also identified five highly supported clusters that together comprise 42 out of 87 (48.3%) BF1 sequences, each cluster containing at least five sequences sharing a similar mosaic structure, suggesting possible new unidentified CRFs_BF1. The divergence time of these five potential new CRFs_BF1 clusters was estimated using a Bayesian approach and indicate that they probably originated between the middle 1980s and the middle 1990s. DNA was extracted from whole blood and four overlapping fragments were amplified by PCR providing full/near full length genomes (FLG/NFLG) and partial genomes. Eleven HIV-1 isolates from Cluster # 5 identified in epidemiologically unlinked individuals living in Central West and North regions provided FLG/NFLG/partial genome sequences with identical mosaic structure. These viruses differ from any known CRF_BF1 reported to date and were named CRF90_BF1 by the Los Alamos National Laboratory. This is the 9th CRF_BF1 described in Brazil and the first one identified in Central West and North regions. Our results highlight the importance of continued molecular screening and surveillance studies, especially of full genome sequences to understand the evolutionary dynamics of the HIV-1 epidemic in a country of continental dimensions as Brazil.

Impact of HIV-1 Subtypes on AIDS Progression in a Brazilian Cohort.

Viral and host factors are known to play a role in the different patterns of AIDS progression. The cocirculation of HIV-1 subtypes B, F1, BBR, and BF1; the occasional detection of HIV-1 subtype D; and an increasing prevalence of subtype C and other recombinant forms have been described in Rio de Janeiro, Brazil. The aim of this study was to evaluate the potential association of HIV-1 subtypes circulating among HIV-1+ individuals in Rio de Janeiro with AIDS disease progression. For this purpose, 246 HIV-1 individuals under clinical and laboratory follow-up from 1986 to 2011 were classified according to their progression to AIDS in typical progressors (n = 133), rapid progressors (n = 95), and long-term nonprogressors (n = 18). The env-gp120 region was amplified and sequenced. Neighbor-joining phylogenetic inferences were performed in Mega 6 and bootscan analysis was performed in Simplot 3.5.1. The Kaplan-Meier method and Cox modeling were performed to determine the time until an AIDS-defining event based on the HIV-1 subtypes/variants. Similar AIDS progression rates were observed among individuals infected with HIV-1 subtype B and variant BBR. However, a direct association between more rapid AIDS progression and HIV-1 subtypes, D and BF1, was confirmed in the multivariate analysis, corroborating previous results. Our findings contribute to the investigation of the possible influence of HIV-1 subtypes in AIDS outcome.

Cross-Neutralizing Antibodies in HIV-1 Individuals Infected by Subtypes B, F1, C or the B/Bbr Variant in Relation to the Genetics and Biochemical Characteristics of the env Gene.

Various HIV-1 env genetic and biochemical features impact the elicitation of cross-reactive neutralizing antibodies in natural infections. Thus, we aimed to investigate cross-neutralizing antibodies in individuals infected with HIV-1 env subtypes B, F1, C or the B/Bbr variant as well as env characteristics. Therefore, plasma samples from Brazilian chronically HIV-1 infected individuals were submitted to the TZM-bl neutralization assay. We also analyzed putative N-glycosylation sites (PNGLs) and the size of gp120 variable domains in the context of HIV-1 subtypes prevalent in Brazil. We observed a greater breadth and potency of the anti-Env neutralizing response in individuals infected with the F1 or B HIV-1 subtypes compared with the C subtype and the variant B/Bbr. We observed greater V1 B/Bbr and smaller V4 F1 than those of other subtypes (p<0.005), however neither was there a correlation verified between the variable region length and neutralization potency, nor between PNLG and HIV-1 subtypes. The enrichment of W at top of V3 loop in weak neutralizing response viruses and the P in viruses with higher neutralization susceptibility was statistically significant (p = 0.013). Some other signatures sites were associated to HIV-1 subtype-specific F1 and B/Bbr samples might influence in the distinct neutralizing response. These results indicate that a single amino acid substitution may lead to a distinct conformational exposure or load in the association domain of the trimer of gp120 and interfere with the induction power of the neutralizing response, which affects the sensitivity of the neutralizing antibody and has significant implications for vaccine design.

Assessing the HIV-1 Epidemic in Brazilian Drug Users: A Molecular Epidemiology Approach.

Person who inject illicit substances have an important role in HIV-1 blood and sexual transmission and together with person who uses heavy non-injecting drugs may have less than optimal adherence to anti-retroviral treatment and eventually could transmit resistant HIV variants. Unfortunately, molecular biology data on such key population remain fragmentary in most low and middle-income countries. The aim of the present study was to assess HIV infection rates, evaluate HIV-1 genetic diversity, drug resistance, and to identify HIV transmission clusters in heavy drug users (DUs). For this purpose, DUs were recruited in the context of a Respondent-Driven Sampling (RDS) study in different Brazilian cities during 2009. Overall, 2,812 individuals were tested for HIV, and 168 (6%) of them were positive, of which 19 (11.3%) were classified as recent seroconverters, corresponding to an estimated incidence rate of 1.58%/year (95% CI 0.92-2.43%). Neighbor joining phylogenetic trees from env and pol regions and bootscan analyses were employed to subtype the virus from132 HIV-1-infected individuals. HIV-1 subtype B was prevalent in most of the cities under analysis, followed by BF recombinants (9%-35%). HIV-1 subtype C was the most prevalent in Curitiba (46%) and Itajaí (86%) and was also detected in Brasília (9%) and Campo Grande (20%). Pure HIV-1F infections were detected in Rio de Janeiro (9%), Recife (6%), Salvador (6%) and Brasília (9%). Clusters of HIV transmission were assessed by Maximum likelihood analyses and were cross-compared with the RDS network structure. Drug resistance mutations were verified in 12.2% of DUs. Our findings reinforce the importance of the permanent HIV-1 surveillance in distinct Brazilian cities due to viral resistance and increasing subtype heterogeneity all over Brazil, with relevant implications in terms of treatment monitoring, prophylaxis and vaccine development.

Association of single nucleotide polymorphisms in the lens epithelium-derived growth factor (LEDGF/p75) with HIV-1 infection outcomes in Brazilian HIV-1+ individuals.

The lens epithelium-derived growth factor p75 (LEDGF/p75), coded by the PSIP1 gene, is an important host co-factor that interacts with HIV-1 integrase to target integration of viral cDNA into active genes. The aim of this study was to investigate the association of SNPs in the PSIP1 gene with disease outcome in HIV-1 infected patients. We performed a genetic association study in a cohort of 171 HIV-1 seropositive Brazilian individuals classified as rapid progressors (RP, n = 69), typical progressors (TP, n = 79) and long-term nonprogressors (LTNP, n = 23). The exonic SNP rs61744944 and 9 tag SNPs were genotyped. A group of 192 healthy subjects was analyzed to determine the frequency of SNPs and haplotypes in the general population. Linkage disequilibrium (LD) analyses indicated that the SNPs analyzed were not in high LD (r2<0.8). Logistic regression models suggested that patients carrying the T allele rs61744944 (472L) were more likely to develop a LTNP phenotype (OR = 4.98; p = 0.05) as compared to TP group. The same trend was observed when LTNPs were compared to the RP group (OR = 3.26). Results of haplotype analyses reinforced this association, since the OR values obtained for the haplotype carrying allele T at rs61744944 also reflected an association with LTNP status (OR = 6.05; p = 0.08 and OR = 3.44; p = 0.12 for comparisons to TP and RP, respectively). The rare missense variations Ile436Ser and Thr473Ile were not identified in the patients enrolled in this study. Gene expression analyses showed lower LEDGF/p75 mRNA levels in peripheral blood mononuclear cells obtained from HIV-1 infected individuals. However, these levels were not influenced by any of the SNPs investigated. In spite of the limited number of LTNPs, these data suggest that the PSIP1 gene could be associated with the outcome of HIV-1 infection. Further analyses of this gene may guide the identification of causative variants to help predict disease course.