Increasing heterosexual transmission of HIV‐1 subtype C in Inland Central Western Brazil

The molecular epidemiology of HIV‐1 in Brazil is complex and heterogeneous because several subtypes co‐circulate with some important regional differences. This study evaluated HIV‐1 subtypes amongst pregnant women living in the metropolitan area and in the interior cities from central western Brazil. From June 2008 to June 2010, 86.9% of confirmed cases of HIV‐1 infection amongst pregnant women (172 out of 198 cases) were recruited in Goiania/Goias state. The HIV‐1 pol gene was sequenced after nested‐PCR. HIV‐1 subtypes were assigned by REGA, phylogenetic, and bootscan analyses. The median age of participants was 26 years (15–41 years range); 58.7% of participants were diagnosed during prenatal care and 51.7% of participants came from >50 interior cities within Goias state. Amongst the 131 HIV‐1 pol sequences, 64.9% were subtype B, 13.0% were BF1 recombinant, 11.4% were subtype C, 7.6% were subtype F1, and 2.3% were BC recombinant. According to the HIV‐1 diagnosis date (1994–2010), a significant increase in subtype C and a decrease of BF1 mosaics were observed over time. All subtype C patients lived in interior cities where the highest prevalence of subtype C outside southern Brazil was observed (18.4%). Phylogenetic analysis revealed multiple independent introductions of the Brazilian subtype C clade from the southern/southeastern regions of Brazil. The HIV‐1 epidemic in women from central western Brazil infected by the heterosexual route is characterized by an unexpectedly high prevalence of subtype C viruses highly related to those circulating in southern/southeastern Brazil. These findings highlight the importance of molecular surveillance programs outside large metropolitan regions in Brazil. J. Med. Virol. 85:396–404, 2013. © 2012 Wiley Periodicals, Inc.     

DC contact with HIV‐1‐infected cells leads to high levels of Env‐mediated virion endocytosis coupled with enhanced HIV‐1 Ag presentation

In HIV‐infected patients, DC are likely to interact with both cell‐free HIV and HIV‐infected cells. We were interested in investigating the mechanism of virus transmission occurring upon contact between HIV‐1‐infected cells and DC, as well as the consequences for HIV‐1 Ag‐presenting activity. By comparing mixed co‐cultures with trans‐well cultures, we observed that cell‐to‐cell contact strongly increased HIV‐1 Env‐mediated virion endocytosis in target DC. This endocytosis was independent of HIV‐1 tropism, de novo infection, HIV‐1 Env‐CD4‐dependent fusion, and immature DC activation/maturation. We also found that augmentation of HIV‐1 endocytosis was closely correlated with strong, Env‐dependent HIV‐1 Ag presentation by DC. Our results provide a better understanding of the mechanisms underlying the induction of the anti‐HIV adaptive immune response.     

Emergence and diversity of different HIV‐1 subtypes in South Africa, 2000–2001

HIV‐1 is a major health problem in South Africa with an average prevalence rate of 29.1% in pregnant women and between 4.9 and 6.1 million people infected. Using env gp120 V3 serotyping and genotyping techniques 410 patient samples were investigated. Most of the samples were obtained from different clinics in the greater Cape Town area of the Western Cape Province in South Africa. These included an academic hospital, state and private clinics, an informal settlement, sex worker cohorts, and the blood transfusion services. RNA was extracted from plasma samples followed by RT‐PCR and sequencing of the env gp120 V3 region. Sequence fragments were assembled using Sequencher V4.7 and subsequently codon aligned. Distance calculation, tree construction methods, and bootstrap analysis were implemented using MEGA version 4.0. Viral load measurements indicated that HIV‐1 RNA levels from 74 samples were below the assay detection limit. Three hundred thirty‐six samples were used for env PCR and sequencing and 320 were assigned to subtypes. The majority of the sequences were subtyped as C (n = 285, 89.0%). Other subtypes detected were subtype A (n = 10, 3.1%); subtype B (n = 22, 6.8%); one each of subtypes F1, G, U, and a CH recombinant. Whether this diversity will have major implications for HIV‐1 evolution and vaccine development in this region remains undetermined. J. Med. Virol. 81:1852–1859, 2009. © 2009 Wiley‐Liss, Inc.     

Predominant human herpesvirus 6 variant A infant infections in an HIV‐1 endemic region of Sub‐Saharan Africa

Human herpesvirus 6, HHV‐6, commonly infects children, causing febrile illness and can cause more severe pathology, especially in an immune compromised setting. There are virulence distinctions between variants HHV‐6A and B, with evidence for increased severity and neurotropism for HHV‐6A. While HHV‐6B is the predominant infant infection in USA, Europe and Japan, HHV‐6A appears rare. Here HHV‐6 prevalence, loads and variant genotypes, in asymptomatic compared to symptomatic infants were investigated from an African region with endemic HIV‐1/AIDS. DNA was extracted from blood or sera from asymptomatic infants at 6 and 18 months age in a population‐based micronutrient study, and from symptomatic infants hospitalised for febrile disease. DNA was screened by qualitative and quantitative real‐time PCR, then genotyped by sequencing at variable loci, U46 (gN) and U47 (gO). HIV‐1 serostatus of infants and mothers were also determined. HHV‐6 DNA prevalence rose from 15% to 22% (80/371) by 18 months. At 6 months, infants born to HIV‐1 positive mothers had lower HHV‐6 prevalence (11%, 6/53), but higher HCMV prevalence (25%, 17/67). HHV‐6 positive febrile hospitalized infants had higher HIV‐1, 57% (4/7), compared to asymptomatic infants, 3% (2/74). HHV‐6A was detected exclusively in 86% (48/56) of asymptomatic HHV‐6 positive samples genotyped. Co‐infections with both strain variants were linked with higher viral loads and found in 13% (7/56) asymptomatic infants and 43% (3/7) HIV‐1 positive febrile infants. Overall, the results show HHV‐6A as the predominant variant significantly associated with viremic infant‐infections in this African population, distinct from other global cohorts, suggesting emergent infections elsewhere. J. Med. Virol. 81:779–789, 2009. © 2009 Wiley‐Liss, Inc.     

Undetectable HIV‐1 RNA load with the Cobas TaqMan v1.0 in a patient diagnosed at the time of primary HIV‐1 infection

Diagnosis of primary HIV‐1 infection is challenging due to the presence of a serological window; thus, HIV‐1‐RNA quantitation and/or measurement of p24 antigenemia are recommended in such cases. A patient was diagnosed at the time of primary HIV‐1 infection, he harbored a CFR02_AG subtype virus; quantitation of plasma HIV‐1‐RNA yielded an undetectable result according to one commercial assay, while HIV‐1‐RNA was detectable when measured with three other assays. J. Med. Virol. 82:1816–1818, 2010. © 2010 Wiley‐Liss, Inc.     

Prevalence of MDR1 C3435T and CYP2B6 G516T polymorphisms among HIV-1 infected South African patients

Data on genetic polymorphisms associated with response to anti-HIV drugs has accumulated over the years. Information on how polymorphisms influence drug metabolism and transport to target sites is important in guiding dosage or selection of appropriate alternative therapies. This study determined the frequency of MDR1 C3435T and CYP2B6 G516T polymorphisms associated with the transport and metabolism of efavirenz and nevirapine, in a population of South African HIV infected patients. In addition, association of polymorphisms with immunologic and virologic factors was investigated. A 207bp of MDR1 exon 26 and a 161bp of CYP2B6 exon 4 were obtained from patients by polymerase chain reaction. Analysis of population-based sequences of MDR1 revealed a frequency of 89% and 11% of C and T alleles respectively (n=197; X^{2} = 0.974; p=0.324). Restriction fragment length polymorphism (RFLP) analysis of the CYP2B6 gene revealed a prevalence of 9.5% of GG, 78.4% of GT and 12.1% of TT genotype (n= 199; X^{2} = 65.204; p=0.00). There was no significant difference between immune recovery and decline in viral load (n=53), with genotype after repeated calculations of analysis of variance (ANOVA).     

Prevalence of persistent and latent viruses in untreated patients infected with HIV‐1 from Ghana,West Africa

Only limited epidemiological data, pertaining to the prevalence of common persistent viruses has been reported in Ghana. This study was conducted to determine the prevalence of persistent viruses in individuals with untreated HIV‐1 infection and uninfected blood donors. Paired plasma and cellular samples from HIV‐negative blood donors, asymptomatic HIV and symptomatic/AIDS cohorts were screened by multiplex PCR then qPCR for parvovirus B19 (B19V), hepatitis B virus (HBV), GB virus‐C (GBV‐C), cytomegalovirus (CMV), Epstein–Barr virus (EBV), human herpesvirus‐8 (HHV‐8) and varicella‐zoster virus (VZV). IgG antibodies specific to each target virus were tested to determine exposure rates. No evidence of viraemia was found for B19V and VZV in any group. Prevalence of GBV‐C plasma viraemia was significantly higher in asymptomatic and symptomatic HIV infection (16.7%) and (16.2%) than in blood donors (4%) P < 0.005. Occult HBV infection was significantly more frequent in symptomatic HIV infection (10.9%) compared to asymptomatic HIV (3.6%) and blood donors (1.6%) P < 0.005. Although there was a high background of EBV viraemia in cellular fractions of blood donors (8.3%), it was significantly higher in asymptomatic (44.6%) and symptomatic HIV (14.6%) P < 0.0001. For CMV, the significantly increased prevalence of viraemia was only observed in the plasma fraction of the symptomatic HIV‐1/AIDS patients (7.6%) compared to asymptomatic individuals (1.8%) and blood donors (0.8%) P ≤ 0.001. The background seroprevalence in blood donors was high for B19V (≥64%), HBV (≥70%), CMV and EBV (≥90%) and was significantly increased in HIV infections for HBV, CMV, VZV (symptomatic HIV), and HHV‐8 (asymptomatic and symptomatic HIV). J. Med. Virol. 81:1860–1868, 2009. © 2009 Wiley‐Liss, Inc.     

Comprehensive analysis of HIV Gag‐specific IFN‐γ response in HIV‐1‐ and HIV‐2‐infected asymptomatic patients from a clinical cohort in The Gambia

Majority of HIV‐2‐infected individuals meet the criteria of long‐term non‐progressors. This has been linked to superior qualitative HIV‐2‐specific cellular immune responses that correlate with viral control. However, it is unknown whether this is due to frequent targeting of immunodominant Gag epitopes in HIV‐2 than HIV‐1 infection. We describe a comprehensive comparison of the magnitude, breadth and frequency of Gag responses and the degree of cross‐recognition of frequently targeted, immunodominant Gag peptides in a cross‐sectional study of asymptomatic HIV‐1‐ and HIV‐2‐infected individuals. Fresh PBMC from 20 HIV‐1‐ and 20 HIV‐2‐infected patients with similar CD4⁺ T‐cell counts (p=0.36) were stimulated with pools of HIV‐1 and/or HIV‐2 Gag peptides in an IFN‐γ ELISPOT assay. We found no difference in the cumulative magnitude of IFN‐γ responses (p=0.75) despite significantly lower plasma viral loads in HIV‐2‐infected people (p<0.0001). However, Gag211–290 was targeted with significantly higher magnitude in HIV‐2‐infected subjects (p=0.03) although this did not correlate with viral control. There was no difference in frequently targeted Gag peptides, the breadth, immunodominance or cross‐recognition of Gag peptide pools between the two infections. This suggests that other factors may control viral replication in HIV‐2 infection.     

NK cells are primed by ANRS MVAHIV‐infected DCs,via a mechanism involving NKG2D and membrane‐bound IL‐15, to control HIV‐1 infection in CD4+ T cells

Natural killer (NK) cells are the major antiviral effector cell population of the innate immune system. It has been demonstrated that NK‐cell activity can be modulated by the interaction with dendritic cells (DCs). The HIV‐1 vaccine candidate Modified Vaccinia Ankara encoding an HIV polypeptide (MVA_HIV), developed by the French National Agency for Research on AIDS (ANRS), has the ability to prime NK cells to control HIV‐1 infection in DCs. However, whether or not MVA_HIV‐primed NK cells are able to better control HIV‐1 infection in CD4⁺ T cells, and the mechanism underlying the specific priming, remain undetermined. In this study, we show that MVA_HIV‐primed NK cells display a greater capacity to control HIV‐1 infection in autologous CD4⁺ T cells. We also highlight the importance of NKG2D engagement on NK cells and DC‐produced IL‐15 to achieve the anti‐HIV‐1 specific priming, as blockade of either NKG2D or IL‐15 during MVA_HIV‐priming lead to a subsequent decreased control of HIV‐1 infection in autologous CD4⁺ T cells. Furthermore, we show that the decreased control of HIV‐1 infection in CD4⁺ T cells might be due, at least in part, to the decreased expression of membrane‐bound IL‐15 (mbIL‐15) on DCs when NKG2D is blocked during MVA_HIV‐priming of NK cells.