HIV-1 Langerhans' cell tropism associated with heterosexual transmission of HIV

Multiple Sexual Partners as Major Predictor of Human Immunodeficiency Virus Seropositivity Among Pregnant Women, Osun State, Nigeria

Concerning human immunodeficiency virus (HIV) epidemiology, pregnant women (PW) are particularly vulnerable and severely affected. Nigeria has over 40 years of HIV epidemiology and enlightenments; to suggest control hub, we sought to know extant variables predicting HIV positivity among PW in selected towns in Osun State. Our hypothesis: none of the study PW's variables predicts HIV seropositivity. With ethics approval from UNIOSUN Health Research Ethics Committee, 900 consecutively selected consenting PW attending antenatal care (ANC) facilities in four towns (capital city inclusive) provided relevant sociodemographic/behavioral data with questionnaire forms; each participant was aseptically bled and plasma screened with the Alere Determine^® Rapid HIV-1/2 Kit. The presumptive reactive plasma samples (and some randomly selected nonreactive samples) were confirmed with Genscreen^® ULTRA HIV-1/2 P²⁴ antigen/antibody ELISA. Microsoft Excel and SPSS 16.0 were used for result analysis using t-test, CHI² test, and binary logistic regression. The PW were 15-50 years of age (n = 900; mean: 26.6 years [95% CI: 26.1-26.9 years]); they were predominantly 15-29 years (71.1%), married (90.8%), with one lifetime sexual partner (86.4%). Seropositive PW by screening and confirmatory tests were, respectively, 14 (1.6% [95% CI: 0.9-2.6%]) and 15 (1.7% [95% CI: 0.9-2.7%]). The latter were predominantly 20-30 years (80.0%), married (93.3%), with ≤ secondary school education (86.7%), reportedly never screened for HIV (60.0%), with 86.7% aware HIV is sexually transmitted. Analysis showed only ≥ three lifetime sexual partners was independently associated with HIV seropositivity (p = 0.03; odds ratio (OR) = 17.0). Although educational status was not associated with seropositivity, PW having primary school education had about 6 times higher likelihood of seropositivity (p = 0.06; OR = 5.7 [95% CI: 0.94-35.1]). Also, primigravida had about twice higher likelihood of seropositivity (p = 0.44; OR = 1.5 [95% CI: 0.54-4.17]). HIV seropositivity was relatively low and majorly predicted by ≥ three lifetime sexual partners; suggesting this as prime focus of HIV counseling among PW attending ANC in Osun State, Nigeria.

Immunovirological Assessment of HIV-Infected Patients and Phylogenetic Analysis of the Virus in Northeast of Iran

Background: The reliable laboratory tests, co-infection with other tumor viruses, and determining the genetic types are very important for therapy and monitoring of the clinical status of human immunodeficiency virus (HIV)-infected subjects. Objectives: This study evaluated the co-infection of HIV with hepatitis B virus (HBV), hepatitis C virus (HCV), and human T-cell leukemia virus type 1 (HTLV-1), the viral load, the progression of infection, and its correlation with the clinical status. Methods: Twenty HIV-infected cases were assessed for T cell subpopulations, HBV, HCV, and HTLV-1 co-infection, as well as the viral load. For phylogenetic relationships analysis, the HIV-c2-v5 fragment and p17 of gag were amplified, sequenced, and then clustered using phylogenetic analysis by MEGA software with maximum-likelihood. Results: The quantity of HIV viral load by qRT-PCR (TaqMan) and Cobas-Amplicor monitor test had a very strong correlation (R = 0.881, P < 0.0001). A significant negative correlation was also found between CD4+ cell count and Cobas-Amplicor (R = -0.41, P = 0.06). A significant negative correlation was also found between CD4+ cell count and Cobas-Amplicor (R = -0.41, P = 0.06) with HIV monitor test results (R = -0.41, P = 0.06). The phylogenetic analysis for p17 regions in gag and c2-v5 in env genes showed that all subjects had AD genotype. The co-infection of the HIV subjects with HBV, HCV, and HTLV-1 was 75%, 75%, and 15%, respectively. A direct correlation was observed between CD8+ and HIV-HTLV-1 co-infection. Conclusions: The results showed that HIV CRF35-AD, (M group) is more frequent in the northeast of Iran, and both real-time quantification methods were reliable for monitoring the HIV-1 viral load. In addition, the transmission rate of HTLV-1 is lower than HBV and HCV among drug abusers.

Genitourinary Infections Related to Circumcision and the Potential Impact on Male Infertility

Male circumcision (MC) is one of the oldest surgical procedures still completed today. Medical indications for MC include phimosis, recurrent balanitis, cosmesis, and infection prevention. In this review, we mainly focus on the role of MC in the prevention of human immunodeficiency virus, human papillomavirus, herpes simplex virus, gonorrhea, chlamydia, chancroid, and syphilis, and the subsequent impact of these genitourinary infections on male fertility. Overall, many compelling data support that MC may play an essential role in both genitourinary infection prevention and male fertility.

Weighing the Evidence of Efficacy of Oral PrEP for HIV Prevention in Women in Southern Africa

As oral tenofovir-based regimens for preexposure prophylaxis (PrEP) are adopted as standard of care for HIV prevention, their utilization in clinical trials among women in southern Africa will require an accurate estimate of oral PrEP efficacy in this population. This information is critical for women in choosing this prevention strategy, and in public health policy making. Estimates of the efficacy of oral PrEP regimens containing tenofovir have varied widely across trials that enrolled women, with some studies reporting high efficacy and others reporting no efficacy. Although poor adherence is strongly associated with lack of efficacy, other factors, such as mode of transmission (sexual vs. parenteral), predominant HIV subtype (C vs. non-C), intensity of exposure, and percentage of stable serodiscordant couples, may also contribute to the variation in efficacy estimates. In this article, we evaluate the evidence for PrEP efficacy in women and propose potential explanations for the observed differences in efficacy among studies. Our review emphasizes the need to continue to refine estimates of efficacy and effectiveness of tenofovir-based oral PrEP so as to best develop the next generation of HIV prevention tools, and to inform public policies directed toward HIV prevention.

Polymorphisms in CCR5Δ32 and Risk of HIV-1 Infection in the Southeast of Caspian Sea, Iran

Prevalence of CCR5Δ32 among blood samples of more than 400 healthy and HIV-1-infected people was investigated in Iran. Polymerase chain reaction (PCR) following DNA extraction was used. Desired frequency was analyzed by Hardy–Weinberg equilibrium (HWE) analysis and SPSS 16.0 software to harvest the results. The prevalence of CCRΔ32 heterozygote genotype was 3% in healthy people and 0.7% in HIV-1–infected individuals. There was no homozygote CCR5Δ32 in both groups, and the allele Δ32 was only observed in 1.5% and 0.36% of healthy and HIV-1–infected participants, respectively. Therefore according to this study, the frequency of the allele CCR5Δ32 indicates no significant difference between either groups (p = 0.18) and it sounds that the mentioned mutation in heterozygote people would not affect their susceptibility against HIV infection. Genotyping trial in Iranians with HIV infection is supposed to be helpful as a matter of prognostic purposes.

Nationwide Trends in Molecular Epidemiology of HIV-1 in China

To estimate the nationwide and regional distribution of HIV-1 genotypes in China in the past three decades, province-specific HIV-1 molecular epidemiology data were derived from 260 independent studies of HIV molecular prevalence through searching PubMed, VIP Chinese Journal Database (VIP), China National Knowledge Infrastructure, and Wanfang Data from January 1981 to December 2015. The nationwide and regional distribution of HIV-1 genotypes was estimated by weighting the genotype distribution from each province- and risk-specific subpopulation with the number of reported cases in the corresponding subgroups in the relevant periods. A sharp transition of HIV-1 subtypes and recombinant distribution was observed in various risk groups and regions over time. CRF01_AE has rapidly surged among almost all risk groups and in all areas, and it has become dominant among men who have sex with men and heterosexuals. A wide variety of new circulating recombinant forms (CRFs) and unique recombinant forms (URFs) were rapidly appearing in several risk groups and regions. After 2007, CRF01_AE was the most prevalent strain, accounting for 42.5% of all national infections, followed by CRF07_BC (28.9%), subtype B'/B (10.9%), CRF08_BC (10.0%), and subtype C (2.8%). URFs and other CRFs were responsible for 2.6% and fewer than 1% of infections nationwide, respectively. The nationwide and regional distributions of HIV-1 subtypes and recombinants were sharply shifting in China. CRF01_AE and new CRFs played an increasing role in the nationwide or regional HIV pandemic. The nationwide diversity of HIV-1 poses a formidable challenge to HIV vaccine development and disease prevention.

Challenges Facing Female Doctoral Students and Recent Graduates

Although increasing the numbers of women and minority faculty in academia is a widely held goal, their numbers remain small. The presence of women and minorities decreases disproportionately at each ascending rung of the academic ladder. This investigation identified factors potentially contributing to attrition in White and non-White women at a critical stage in their careers: as doctoral candidates and recent graduates. Two-hundred and twenty-four women in the life sciences, social sciences, and the humanities described their most pressing professional and personal concerns and offered suggestions for changes in their fields and in academia more generally. Independent raters coded responses by thematic content. Differences in responses by field, educational status, and minority status were examined. The most frequently cited concerns involved practical issues such as finding employment, financial stability, and developing professional expertise, revealing widespread concerns about a competitive academic climate. Suggestions included modifications in professional conduct, the employment and pay structure, and training.

Human Immunodeficiency Virus Localization in Human Papillomavirus-Related, High-Grade Squamous Intraepithelial Lesions of the Cervix in Women with HIV Infection: Microdissection and Molecular Analysis on Formalin-Fixed and Paraffin-Embedded Specimens

OBJECTIVES

To evaluate a possible mechanism of human immunodeficiency virus (HIV) and human papillomavirus (HPV) interaction, we have identified the cervical tissue compartments that harbor HIV.

MATERIALS AND METHODS

We studied 39 paraffin-embedded, cervical conization specimens with high-grade cervical intraepithelial neoplasia (CIN3) occurring in HIV-infected women. From selected intraepithelial HPV-positive nonulcerated specimens (confirmed by in situ hybridization), we obtained serial 4- to 5-μm-thick sections that were stained with hematoxylin and eosin, anti-S100 protein, and anti-CD4. The presence of intramucosal Langerhans' cells or dendritic cells or CD4-positive cells was recorded. Three consecutive, nonmicrodissected, full-thickness sections of the same specimens were used for polymerase chain reaction (PCR) analysis (group A). Three other uncovered, consecutive sections from the same blocks were examined with an inverted microscope, and full-thickness specimens of mucosa were dissected from the underlying cervical stroma, were gently removed, and were used for PCR (group B). The quality of DNA was checked by HLA-DQa amplification; then a nested PCR for HIV proviral DNA was performed.

RESULTS

Of group A, 5 of 39 cases (12.8%) were positive, whereas HIV was not detected in the microdissected sections of group B, with or without intraepithelial Langerhans' or CD4 cells.

CONCLUSIONS

HIV does not affect cervical epithelium. The absence of infected Langerhans' or dendritic cells (or both) indicates a migration to the proximal lymph nodes of the in ….

Detection of new mutant sites of HIV-1 coreceptor CCR5 among Saudi populations

The genetic association of CCR5 with human immunodeficiency virus-1 (HIV-1) pathogenesis is well known. The HIV-1 entry into target cells is initiated by the binding of the viral envelope glycoproteins (gp120-gp41) with the cell surface receptor (CD4) and the coreceptor (CCR5), followed by fusion of the viral and cell membranes. Genetic variants of the gene-encoding HIV-1 coreceptor are implicated in the susceptibility to HIV-1 infection. The prevalence of these mutations may vary according to population ethnicity. In the current study, characterization and frequency distribution of the HIV-related gene variants in 135 samples of the Saudi populations were conducted. Polymerase chain reaction (PCR) of 276 bp amplicons was used to rapidly detect Δ32 deletion in the initial sample of DNA. The direct sequence of 2 overlapping PCR amplicons flanking 1,059 bp was used to detect single-nucleotide polymorphisms. A single hetrozygous Δ32 deletion allele and 6 single-nucleotide polymorphisms were detected. Only one of the identified haplotypes, Taif-1, which was found in the majority of the tested sample, is identical to CCR5 wild-type alleles. Furthermore, the results of this study raised a concern about the prospective role of the mutations detected among Saudi nationals in the HIV pathogenesis and the clinical use of CCR5 antagonists, which are currently being developed as therapeutics for HIV-1 and inflammatory diseases.

HIV-1 Trans Infection of CD4(+) T Cells by Professional Antigen Presenting Cells

Since the 1990s we have known of the fascinating ability of a complex set of professional antigen presenting cells (APCs; dendritic cells, monocytes/macrophages, and B lymphocytes) to mediate HIV-1 trans infection of CD4(+) T cells. This results in a burst of virus replication in the T cells that is much greater than that resulting from direct, cis infection of either APC or T cells, or trans infection between T cells. Such APC-to-T cell trans infection first involves a complex set of virus subtype, attachment, entry, and replication patterns that have many similarities among APC, as well as distinct differences related to virus receptors, intracellular trafficking, and productive and nonproductive replication pathways. The end result is that HIV-1 can sequester within the APC for several days and be transmitted via membrane extensions intracellularly and extracellularly to T cells across the virologic synapse. Virus replication requires activated T cells that can develop concurrently with the events of virus transmission. Further research is essential to fill the many gaps in our understanding of these trans infection processes and their role in natural HIV-1 infection.

Dendritic Cells in HIV-1 and HCV Infection: Can They Help Win the Battle?

Persistent infections with human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) are a major cause of morbidity and mortality worldwide. As sentinels of our immune system, dendritic cells (DCs) play a central role in initiating and regulating a potent antiviral immune response. Recent advances in our understanding of the role of DCs during HIV-1 and HCV infection have provided crucial insights into the mechanisms employed by these viruses to impair DC functions in order to evade an effective immune response against them. Modulation of the immunological synapse between DC and T-cell, as well as dysregulation of the crosstalk between DCs and natural killer (NK) cells, are emerging as two crucial mechanisms. This review focuses on understanding the interaction of HIV-1 and HCV with DCs not only to understand the immunopathogenesis of chronic HIV-1 and HCV infection, but also to explore the possibilities of DC-based immunotherapeutic approaches against them. Host genetic makeup is known to play major roles in infection outcome and rate of disease progression, as well as response to anti-viral therapy in both HIV-1 and HCV-infected individuals. Therefore, we highlight the genetic variations that can potentially affect DC functions, especially in the setting of chronic viral infection. Altogether, we address if DCs’ potential as critical effectors of antiviral immune response could indeed be utilized to combat chronic infection with HIV-1 and HCV.

Bidirectional NK/DC interactions promote CD4 expression on NK cells, DC maturation, and HIV infection

Interactions between natural killer (NK) and dendritic cells (DCs) are integral to immune response development, potentially leading to bidirectional NK/DC activation. We demonstrate that autologous NK/DC interactions induce CD4 expression on NK cells, influencing degranulation. Cell contact is required, with high NK:DC ratios and mature DCs most effectively inducing CD4 expression. CD4(+) NK cells, in turn, mediate DC maturation via contact-dependent and independent pathways, more effectively maturing DCs than CD4(-) NK cells. Bidirectional NK/DC interactions also impact HIV infection, as NK-matured DCs effectively deliver infectious HIV to T cells, via trans-infection. DC-induced CD4 expression also renders NK cells susceptible to HIV infection. Focusing on NK/DC interactions, DCs can transfer infectious virus and enhance HIV infection of CD4(+) NK cells, strongly suggesting that these interactions influence HIV pathogenesis. Findings provide new insight regarding NK/DC interactions, defining a mechanism by which cellular interactions in the absence of pathogens promote DC-mediated amplification of HIV infection.

HIV impairment of immune responses in dendritic cells

Dendritic cells and their subsets are diverse populations of immune cells in the skin and mucous membranes that possess the ability to sense the presence of microbes and orchestrate an efficient and adapted immune response. Dendritic cells (DC) have the unique ability to act as a bridge between the innate and adaptive immune responses. These cells are composed of a number of subsets behaving with preferential and specific features depending on their location and surrounding environment. Langerhans cells (LC) or dermal DC (dDC) are readily present in mucosal areas. Other DC subsets such as plasmacytoid DC (pDC), myeloid DC (myDC), or monocyte-derived DC (MDDC) are thought to be recruited or differentiated in sites of pathogenic challenge. Upon HIV infection, DC and their subsets are likely among the very first immune cells to encounter incoming pathogens and initiate innate and adaptive immune responses. However, as evidenced during HIV infection, some pathogens have evolved subtle strategies to hijack key cellular machineries essential to generate efficient antiviral responses and subvert immune responses for spread and survival.In this chapter, we review recent research aimed at investigating the involvement of DC subtypes in HIV transmission at mucosal sites, concentrating on HIV impact on cellular signalling and trafficking pathways in DC leading to DC-mediated immune response alterations and viral immune evasion. We also address some aspects of DC functions during the chronic immune pathogenesis and conclude with an overview of the current and novel therapeutic and prophylactic strategies aimed at improving DC-mediated immune responses, thus to potentially tackle the early events of mucosal HIV infection and spread.

Study of HIV-1 subtypes in serodiscordant couples attending an integrated counselling and testing centre in Mumbai using heteroduplex mobility analysis and DNA sequencing

AIMS

To determine the prevalent subtypes of HIV-1 in serodiscordant couples.

SETTING

Integrated Counselling and Testing Centre (ICTC), Department of Microbiology.

STUDY DESIGN

Prospective pilot study.

PARTICIPANTS

Thirty HIV-1 serodiscordant couples.

INCLUSION CRITERIA

a) Documentation of HIV-1 infection in one partner and seronegative status in the other, current history of continued unprotected sexual activity within the partnership, demonstration that they have been in a partnership for at least 1 year and are not currently on highly active antiretroviral therapy HAART; b) willingness of both partners to provide written informed consent including consent to continued couple counselling for 3 months.

MATERIALS AND METHODS

HIV-1 subtyping was carried out by heteroduplex mobility analysis (HMA) by amplifying env region; and DNA sequencing by amplifying gag region.

RESULTS

HIV-1 env gene was amplified successfully in 10/30 samples; gag gene, in 25/30 samples; and both env and gag gene were amplified successfully in 5/30 samples. HIV-1 subtype C was detected from 21 samples; subtype B, from 7; and subtype A, from 2. Sample from 1 positive partner was detected as subtype C by env HMA and subtype B by gag sequencing.

CONCLUSION

HIV-1 subtype C was found to be the predominant subtype of HIV-1 in serodiscordant couples attending our ICTC, followed by HIV-1 subtype B and HIV-1 subtype A, respectively. DNA sequencing was found to be the most reliable method for determining the subtypes of HIV-1.

Biological factors that may contribute to regional and racial disparities in HIV prevalence

Despite tremendous regional and subregional disparities in HIV prevalence around the world, epidemiology consistently demonstrates that black communities have been disproportionately affected by the pandemic. There are many reasons for this, and a narrow focus on socio-behavioural causes may be seen as laying blame on affected communities or individuals. HIV sexual transmission is very inefficient, and a number of biological factors are critical in determining whether an unprotected sexual exposure to HIV results in productive infection. This review will focus on ways in which biology, rather than behaviour, may contribute to regional and racial differences in HIV epidemic spread. Specific areas of focus are viral factors, host genetics, and the impact of co-infections and host immunology. Considering biological causes for these racial disparities may help to destigmatize the issue and lead to new and more effective strategies for prevention.

Diversity of HIV-1 subtype B: implications to the origin of BF recombinants

BACKGROUND

The HIV-1 subtype B epidemic in Brazil is peculiar because of the high frequency of isolates having the GWGR tetramer at V3 loop region. It has been suggested that GWGR is a distinct variant and less pathogenic than other subtype B isolates.

METHODOLOGY/PRINCIPAL FINDINGS

Ninety-four percent of the HIV-1 subtype B worldwide sequences (7689/8131) obtained from the Los Alamos HIV database contain proline at the tetramer of the V3 loop of the env gene (GPGR) and only 0.74% (60/8131) have tryptophan (GWGR). By contrast, 48.4% (161/333) of subtype B isolates from Brazil have proline, 30.6% (102/333) contain tryptophan and 10.5% (35/333) have phenylalanine (F) at the second position of the V3 loop tip. The proportion of tryptophan and phenylalanine in Brazilian isolates is much higher than in worldwide subtype B sequences (chi-square test, p = 0.0001). The combined proportion of proline, tryptophan and phenylalanine (GPGR+GWGR+GFGR) of Brazilian isolates corresponds to 89% of all amino acids in the V3 loop. Phylogenetic analysis revealed that almost all subtype B isolates in Brazil have a common origin regardless of their motif (GWGR, GPGR, GGGR, etc.) at the V3 tetramer. This shared ancestral origin was also observed in CRF28_BF and CRF29_BF in a genome region (free of recombination) derived from parental subtype B. These results imply that tryptophan substitution (e.g., GWGR-to-GxGR), which was previously associated with the change in the coreceptor usage within the host, also occurs at the population level.

CONCLUSIONS/SIGNIFICANCE

Based on the current findings and previous study showing that tryptophan and phenylalanine in the V3 loop are related with coreceptor usage, we propose that tryptophan and phenylalanine in subtype B isolates in Brazil are kept by selective mechanisms due to the distinct coreceptor preferences in target cells of GWGR, GFGR and GFGR viruses.

Nanotechnology-based systems for the treatment and prevention of HIV/AIDS

The HIV/AIDS pandemic is an increasing global burden with devastating health-related and socioeconomic effects. The widespread use of antiretroviral therapy has dramatically improved life quality and expectancy of infected individuals, but limitations of currently available drug regimens and dosage forms, alongside with the extraordinary adapting capacity of the virus, have impaired further success. Alongside, circumventing the escalating number of new infections can only be attained with effective and practical preventative strategies. Recent advances in the field of drug delivery are providing evidence that engineered nanosystems may contribute importantly for the enhancement of current antiretroviral therapy. Additionally, groundwork is also being carried out in the field nanotechnology-based systems for developing preventative solutions for HIV transmission. This manuscript reviews recent advances in the field of nanotechnology-based systems for the treatment and prevention of HIV/AIDS. Particular attention is given to antiretroviral drug targeting to HIV reservoirs and the usefulness of nanosystems for developing topical microbicides and vaccines.

RNA virus genomics: a world of possibilities

The increasing availability of complete genome sequences of RNA viruses has the potential to shed new light on fundamental aspects of their biology. Here, I use case studies of 3 RNA viruses to explore the impact of genomic sequence data, with particular emphasis on influenza A virus. Notably, the studies of RNA virus genomics undertaken to date largely focused on issues of evolution and epidemiology, and they have given these disciplines new impetus. However, genomic data have so far made fewer inroads into areas of more direct importance for disease, prevention, and control; thus, harnessing their full potential remains an important goal.

HIV infection and associated risk factors among long-distance truck drivers travelling through Azerbaijan

The aim of this study was to assess HIV prevalence and associated risk behaviours among international truck drivers (TDs) in Azerbaijan. The subjects signed consent and completed a questionnaire. Blood was tested using two rapid HIV tests: Determine and OraQuick. Genotyping was performed on 13 positives. Overall, 3763 TDs from 21 countries were enrolled. Fifty-eight (1.54%) were HIV-positive. Highest prevalence was among Russians (2.88%), Ukrainians (1.66%) and Azerbaijani (1.09%). On univariate analysis, highest prevalence (60%) was among injecting drug users (IDUs) compared with 0.4% among non-IDUs (P < 0.001). The prevalence in men who had sex with men (MSM) (42.9%) was high (P </= 0.001). On multivariate analysis, IDUs and MSM remained as the main HIV independent risk factors. Additional risk factors include no condom use, no circumcision and a history of an sexually transmitted infection. Eleven of 13 samples were subtype A. In conclusion, HIV was highly associated with IDU and MSM. The detected HIV subtypes A and B are those predominant in the former Soviet Union.

Male circumcision for prevention of heterosexual acquisition of HIV in men

BACKGROUND

Male circumcision is defined as the surgical removal of all or part of the foreskin of the penis and may be practiced as part of a religious ritual, as a medical procedure, or as part of a traditional ritual performed as an initiation into manhood. Since the 1980s, over 30 observational studies have suggested a protective effect of male circumcision on HIV acquisition in heterosexual men. In 2002, three randomised controlled trials to assess the efficacy of male circumcision for preventing HIV acquisition in men commenced in Africa. This review evaluates the results of these trials, which analysed the effectiveness and safety of male circumcision for preventing acquisition of HIV in heterosexual men.

OBJECTIVES

To assess the evidence of an interventional effect of male circumcision for preventing acquisition of HIV-1 and HIV-2 by men through heterosexual intercourse

SEARCH STRATEGY

We formulated a comprehensive and exhaustive search strategy in an attempt to identify all relevant studies regardless of language or publication status (published, unpublished, in press, and in progress). In June 2007 we searched the following electronic journal and trial databases: MEDLINE, EMBASE, and CENTRAL. We also searched the electronic conference databases NLM Gateway and AIDSearch and the trials registers ClinicalTrials.gov and Current Controlled Trials. We contacted researchers and relevant organizations and checked reference lists of all included studies.

SELECTION CRITERIA

Randomised controlled trials of male circumcision versus no circumcision in HIV-negative heterosexual men with HIV incidence as the primary outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data, and graded methodological quality. Data extraction and methodological quality were checked by a third author who resolved differences when these arose. Data were considered clinically homogeneous and meta-analyses and sensitivity analyses were performed.

MAIN RESULTS

Three large RCTs of men from the general population were conducted in South Africa (N = 3 274), Uganda (N = 4 996) and Kenya (N = 2 784) between 2002 and 2006. All three trials were stopped early due to significant findings at interim analyses. We combined the survival estimates for all three trials at 12 months and also at 21 or 24 months in a meta-analysis using available case analyses using the random effects model. The resultant incidence risk ratio (IRR) was 0.50 at 12 months with a 95% confidence interval (CI) of 0.34 to 0.72; and 0.46 at 21 or 24 months (95% CI: 0.34 to 0.62). These IRRs can be interpreted as a relative risk reduction of acquiring HIV of 50% at 12 months and 54% at 21 or 24 months following circumcision. There was little statistical heterogeneity between the trial results (chi(2) = 0.60; df = 2; p = 0.74 and chi(2) = 0.31; df = 2; p = 0.86) with the degree of heterogeneity quantified by the I(2) at 0% in both analyses. We investigated the sensitivity of the calculated IRRs and conducted meta-analyses of the reported IRRs, the reported per protocol IRRs, and reported full intention-to-treat analysis. The results obtained did not differ markedly from the available case meta-analysis, with circumcision displaying significant protective effects across all analyses.We conducted a meta-analysis of the secondary outcomes measuring sexual behaviour for the Kenyan and Ugandan trials and found no significant differences between circumcised and uncircumcised men. For the South African trial the mean number of sexual contacts at the 12-month visit was 5.9 in the circumcision group versus 5 in the control group, which was a statistically significant difference (p < 0.001). This difference remained statistically significant at the 21-month visit (7.5 versus 6.4; p = 0.0015). No other significant differences were observed.Incidence of adverse events following the surgical circumcision procedure was low in all three trials.Reporting of methodological quality was variable across the three trials, but overall, the potential for significant biases affecting the trial results was judged to be low to moderate given the large sample sizes of the trials, the balance of possible confounding variables across randomised groups at baseline in all three trials, and the employment of acceptable statistical early stopping rules.

AUTHORS' CONCLUSIONS

There is strong evidence that medical male circumcision reduces the acquisition of HIV by heterosexual men by between 38% and 66% over 24 months. Incidence of adverse events is very low, indicating that male circumcision, when conducted under these conditions, is a safe procedure. Inclusion of male circumcision into current HIV prevention measures guidelines is warranted, with further research required to assess the feasibility, desirability, and cost-effectiveness of implementing the procedure within local contexts.

Heterosexual risk of HIV-1 infection per sexual act: systematic review and meta-analysis of observational studies

We did a systematic review and meta-analysis of observational studies of the risk of HIV-1 transmission per heterosexual contact. 43 publications comprising 25 different study populations were identified. Pooled female-to-male (0.04% per act [95% CI 0.01-0.14]) and male-to-female (0.08% per act [95% CI 0.06-0.11]) transmission estimates in high-income countries indicated a low risk of infection in the absence of antiretrovirals. Low-income country female-to-male (0.38% per act [95% CI 0.13-1.10]) and male-to-female (0.30% per act [95% CI 0.14-0.63]) estimates in the absence of commercial sex exposure (CSE) were higher. In meta-regression analysis, the infectivity across estimates in the absence of CSE was significantly associated with sex, setting, the interaction between setting and sex, and antenatal HIV prevalence. The pooled receptive anal intercourse estimate was much higher (1.7% per act [95% CI 0.3-8.9]). Estimates for the early and late phases of HIV infection were 9.2 (95% CI 4.5-18.8) and 7.3 (95% CI 4.5-11.9) times larger, respectively, than for the asymptomatic phase. After adjusting for CSE, presence or history of genital ulcers in either couple member increased per-act infectivity 5.3 (95% CI 1.4-19.5) times versus no sexually transmitted infection. Study estimates among non-circumcised men were at least twice those among circumcised men. Low-income country estimates were more heterogeneous than high-income country estimates, which indicates poorer study quality, greater heterogeneity of risk factors, or under-reporting of high-risk behaviour. Efforts are needed to better understand these differences and to quantify infectivity in low-income countries.

Antiretroviral resistance in individuals presenting therapeutic failure and subtypes of the human immunodeficiency virus type 1 in the Northeast Region of Brazil

This study aimed to analyze human immunodeficiency virus (HIV) mutation profiles related to antiretroviral resistance following therapeutic failure, and the distribution of hiv subtypes in the Northeast Region of Brazil. A total of 576 blood samples from AIDS patients presenting therapeutic failure between 2002 and 2004 were analyzed. The genotyping kit viroSeq was used to perform viral amplification in order to identify mutations related to hiv pol gene resistance. An index of 91.1% of the patients presented mutations for nucleoside reverse transcriptase inhibitors (nrti), 58.7% for non-nucleoside reverse transcriptase inhibitors (nnrti), and 94.8% for protease inhibitors (pi). The most prevalent mutations were 184V and 215E for nrti, 103N and 190A for nnrti. Most mutations associated with PIs were secondary, but significant frequencies were observed in codons 90 (25.2%), 82 (21.1%), and 30 (16.2%). The resistance index to one class of antiretrovirals was 14%, to two classes of antiretrovirals 61%, and to three classes 18.9%. Subtype B was the most prevalent (82.4%) followed by subtype F (11.8%). The prevalence of mutations related to nrti and nnrti was the same in the two subtypes, but codon analysis related to PI showed a higher frequency of mutations in codon 63 in subtype B and in codon 36 in subtype F. The present study showed that there was a high frequency of primary mutations, which offered resistance to nrti and nnrti. Monitoring patients with treatment failure is an important tool for aiding physicians in rescue therapy.

Impact of human immunodeficiency virus (HIV) subtypes on HIV-associated neurological disease

Among the many variables affecting transmission and pathogenesis of the human immunodeficiency virus type 1(HIV-1), the effects of HIV subtypes, or clades, on disease progression remain unclear. Although debated, some studies have found that the variable env and pol sequences of different subtypes of HIV-1 may endow some subtypes with greater degrees of cell tropism, virulence, and drug resistance, which may lead to differences in overall disease progression. HIV-associated dementia (HAD) appears to be associated with viral diversity and markers of immune activation. Africa has the highest prevalence of HIV, largest viral diversity, and is where clade recombination occurs most frequently. All of these factors would suggest that HAD would pose the largest threat in this region of the world. Although investigations into the effects of different subtypes on overall disease progression are well documented, few have looked into the effects of subtypes on neurological disease progression. This review highlights the need for more international research involving the neurological effects and especially the clinical presentation of dementia for the entire range of the group M HIV-1 subtypes.

Molecular epidemiology of HIV-1 in Santa Catarina State confirms increases of subtype C in Southern Brazil

Recent studies have demonstrated an increased prevalence of human immunodeficiency virus type 1 (HIV-1) subtype C in southern Brazil. Although Santa Catarina State (SC) is located in this area and presents one of the country's highest incidences of HIV/AIDS, knowledge on the molecular epidemiology of HIV-1 in such State is lacking. The aim of this study was to investigate the HIV-1 molecular diversity and epidemiological profile of HIV-1-infected patients from SC. DNA samples were PCR amplified and HIV-1 subtypes were determined using both env and gag genes by direct sequencing. Phylogenetic analyses revealed that 48% were subtype C and 23% were subtype B. Possible recombinant forms were observed for both B/C (23%) and B/F (6%) subtypes. Our results, for the first time, identifies HIV-1 subtype C as a major clade circulating in SC and contributes to the understanding of HIV epidemics in the country by confirming the epidemic spread of the HIV-1 subtype C in southern Brazil.

Clinical impact of HIV-1 subtype: are there important differences?

The enormous genetic diversity of HIV-1 is a major challenge to vaccine development and may have important clinical consequences. HIV-1 group M predominates globally, with nine subtypes, several sub-subtypes and over 30 circulating recombinant forms that may exhibit differences with respect to transmissibility, pathogenicity and development of antiretroviral resistance. Subtype D appears to be more virulent than other subtypes, in particular subtype A. Subtype C may be less virulent and more transmissible, although the evidence for this is inconclusive. All group M non-B subtypes appear to be equally susceptible to combination antiretroviral therapy, but development of resistance mutations may vary significantly between subtypes. Further research into the clinical implications of HIV-1 diversity is crucial for effective HIV-1 prevention and treatment.

Aberrant life cycle of human immunodeficiency virus type 1 CRF15_01B-like clinical isolates from Thailand in human CD4+ T-cell lines

Human immunodeficiency virus type 1 (HIV-1) is separated into several subtypes and circulating recombinant forms (CRFs). Here, infections of 4 clinical isolates (0-47-1, CU98-26, CU98-28, and CU98-31) from Thailand were examined in human CD4(+) T-cell lines, MT-4 and MOLT-4. The CU98-26 isolates in both cells and 0-47-1 in MT-4 established chronic infections, as in control 2 subtype B isolates from Japan, while 0-47-1 in MOLT-4 caused a latent infection. In contrast, CU98-28 and CU98-31 established aberrant infections in both cells. Integrated provirus was detected in all the chronic infections, including 0-47-1 in both cells. In contrast, extrachromosomal circular forms of HIV-1 DNA were detected in CU98-28- and CU98-31-infected cells, whereas the amount of the integrated form was below the limit of detection. Interestingly, phylogenetic trees and sequencing revealed that all the Thai isolates, except 0-47-1, displayed CRF15_01B-like mosaic structures of CRF01_AE with subtype B-like sequences in several regions that were apparently different from those of the inocula in peripheral blood mononuclear cells. Thus, in the infections of most of the above Thai isolates it was suggested that a minor population with mosaic patterns having multiple breakpoints between CRF01_AE and subtype B in the inocula could be selected by the T-cell lines.

Dendritic-cell interactions with HIV: infection and viral dissemination

Dendritic cells (DCs) are crucial for the generation and the regulation of adaptive immunity. Because DCs have a pivotal role in marshalling immune responses, HIV has evolved ways to exploit DCs, thereby facilitating viral dissemination and allowing evasion of antiviral immunity. Defining the mechanisms that underlie cell-cell transmission of HIV and understanding the role of DCs in this process should help us in the fight against HIV infection. This Review highlights the latest advances in our understanding of the interactions between DCs and HIV, focusing on the mechanisms of DC-mediated viral dissemination.

Distribution of the HIV resistance CCR5-Delta32 allele among Egyptians and Syrians

A mutant allele of the beta-chemokine receptor gene CCR5 bearing a 32-basepair (bp) deletion that prevents cell invasion by the primary transmitting strain of HIV-1 has recently been characterized. Individuals homozygous for the mutation are resistant to infection, even after repeated high-risk exposure, but this resistance appears not absolute, as isolated cases of HIV-positive deletion homozygotes are emerging. The consequence of the heterozygous state is not clear, but it may delay the progression to AIDS in infected individuals. In order to evaluate the frequency distribution of CCR5-Delta32 polymorphism among Egyptians, a total of 200 individuals (154 from Ismailia and 46 from Sinai) were tested. Only two heterozygous individuals from Ismailia carried the CCR5-Delta32 allele (0.6%), and no homozygous (Delta32/Delta32) individuals were detected among the tested samples. The presence of the CCR5-Delta32 allele among Egyptians may be attributed to the admixture with people of European descent. Thus we conclude that the protective deletion CCR5-Delta32 is largely absent in the Egyptian population.

Efficiency of human immunodeficiency virus transmission through injections and other medical procedures: evidence, estimates, and unfinished business

OBJECTIVE

To estimate the transmission efficiency of human immunodeficiency virus (HIV) through medical injections and other invasive procedures.

DESIGN

We searched our own files and Medline (from 1966-2004, using the keywords ["iatrogenic" or "nosocomial" or "injections"] and "HIV") for reports of iatrogenic outbreaks worldwide, except outbreaks traced to receipt of contaminated blood or blood products. We also analyzed information from a case-control study of percutaneous exposures to healthcare workers.

SETTING

Worldwide healthcare settings. EVENTS: We identified 8 iatrogenic outbreaks that met our study criteria; published information from 4 outbreaks was sufficient to estimate transmission efficiency.

RESULTS

From the 4 documented iatrogenic outbreaks, we estimated that 1 iatrogenic infection occurred after 8-52 procedures involving HIV-infected persons. Although only 0.3% of healthcare workers seroconvert after percutaneous exposure, a case-control study reported that deep injuries and other risk factors collectively increased seroconversion risk by as much as 50 times. Laboratory investigations demonstrate HIV survival through time and various rinsing regimens. We estimate that the transmission efficiency in medical settings with no or grossly insufficient efforts to clean equipment ranges from 0.5% to 3% for lower risk procedures (eg, intramuscular injections) and from 10% to 20% or more for high-risk procedures. Efforts to clean equipment, short of sterilization, may cut the transmission efficiency by 0%-100%. Procedures that contaminate multidose vials may accelerate transmission efficiency.

CONCLUSION

To achieve better estimates of the transmission efficiency for a range of medical procedures and settings, investigations of iatrogenic outbreaks should be accorded high priority.

Molecular analysis and phylogenetic characterization of HIV in Iran

The rate of human immunodeficiency virus type 1 (HIV-1) infection in Iran has increased dramatically in the last few years. While the earliest cases were found in hemophiliacs, intravenous drug users are now fueling the outbreak. In this study, both the 122 clones of HIV-1 gag p17 and the 131 clones of env V1-V5 region were obtained from 61 HIV-1 seropositives belonging to these two groups in Iran. HIV-1 subtyping and phylogenetic analysis was done by heteroduplex mobility assays (HMA) and multiple clone sequencing. The result indicated all hemophiliacs are infected with HIV-1 subtype B and all intravenous drug users are infected with HIV-1 subtype A. Since intravenous drug abuse is the major transmission route in Iran, HIV-1 subtype A is likely to be the dominant viral subtype circulating in the country. The analysis of genetic distances showed subtype B viruses in Iran to be twice as heterogeneous as the subtype A viruses. In conclusion, this first molecular study of HIV-1 genotypes in Iran suggests two parallel outbreaks in distinct high-risk populations and may offer clues to the origin and spread of infection in Iran.

HIV/AIDS epidemiology, pathogenesis, prevention, and treatment

The HIV-1 pandemic is a complex mix of diverse epidemics within and between countries and regions of the world, and is undoubtedly the defining public-health crisis of our time. Research has deepened our understanding of how the virus replicates, manipulates, and hides in an infected person. Although our understanding of pathogenesis and transmission dynamics has become more nuanced and prevention options have expanded, a cure or protective vaccine remains elusive. Antiretroviral treatment has transformed AIDS from an inevitably fatal condition to a chronic, manageable disease in some settings. This transformation has yet to be realised in those parts of the world that continue to bear a disproportionate burden of new HIV-1 infections and are most affected by increasing morbidity and mortality. This Seminar provides an update on epidemiology, pathogenesis, treatment, and prevention interventions pertinent to HIV-1.

Gene expression profiling of the host response to HIV-1 B, C, or A/E infection in monocyte-derived dendritic cells

Dendritic cells (DC) are among the first targets of human immunodeficiency virus type-1 (HIV-1) infection and in turn play a crucial role in viral transmission to T cells and in the regulation of the immune response. The major group of HIV-1 has diversified genetically based on variation in env sequences and comprise at least 11 subtypes. Because little is known about the host response elicited against different HIV-1 clade isolates in vivo, we sought to use gene expression profiling to identify genes regulated by HIV-1 subtypes B, C, and A/E upon de novo infection of primary immature monocyte-derived DC (iMDDCs). A total of 3700 immune-related genes were subjected to a significance analysis of microarrays (SAM); 656 genes were selected as significant and were further divided into 8 functional categories. Regardless of the time of infection, 20% of the genes affected by HIV-1 were involved in signal transduction, followed by 14% of the genes identified as transcription-related genes, and 7% were classified as playing a role in cell proliferation and cell cycle. Furthermore, 7% of the genes were immune response genes. By 72 h postinfection, genes upregulated by subtype B included the inhibitor of the matrix metalloproteinase TIMP2 and the heat shock protein 40 homolog (Hsp40) DNAJB1, whereas the IFN inducible gene STAT1, the MAPK1/ERK2 kinase regulator ST5, and the chemokine CXCL3 and SHC1 genes were induced by subtypes C and A/E. These analyses distinguish a temporally regulated host response to de novo HIV-1 infection in primary dendritic cells.

Potential HIV-1 target cells in the human penis

OBJECTIVES

To study the distribution of HIV-1 receptors and degree of keratinization in the human penis.

DESIGN

Formalin-fixed penises were obtained from nine uncircumcised cadavers. Foreskins were obtained from 21 healthy adult men undergoing elective circumcision for social reasons. Uncircumcised penises were obtained within 24 h of death from eight men. All tissues were stained for keratin and HIV-1 receptors.

METHODS

Penises from nine formalin fixed cadavers aged 64-80 years were obtained from the Department of Anatomy, University of Melbourne. Foreskins were obtained from 21 men aged 18-64 years following circumcision performed at either the Freemason's or Mercy Private Hospitals, Melbourne, Australia. Fresh penile necropsy specimens from eight uncircumcised men aged 23-63 years were obtained from the Victorian Institute of Forensic Medicine, Melbourne. The degree of keratinization was scored, and the distribution of HIV-1 susceptible cells was mapped in the glans penis, penile urethra, urethral meatus, frenulum and foreskin.

RESULTS

Cells with HIV-1 receptors were present in all penile epithelia, but Langerhans' cells were most superficial in the inner foreskin and frenulum. The inner foreskin had a significantly thinner keratin layer (1.8 +/- 0.1 units), than the outer foreskin (3.3 +/- 0.1), or glans penis (3.3 +/- 0.2), P < 0.05.

CONCLUSIONS

Superficial Langerhans' cells on the inner aspect of the foreskin and frenulum are poorly protected by keratin and thus could play an important role in primary male infection. These findings provide a possible anatomical explanation for the epidemiologically observed protective effect of male circumcision.

Oral transmission of HIV, reality or fiction? An update

Human immunodeficiency virus (HIV) and many other viruses can be isolated in blood and body fluids, including saliva, and can be transmitted by genital-genital and especially anal-genital sexual activity. The risk of transmission of HIV via oral sexual practices is very low. Unlike other mucosal areas of the body, the oral cavity appears to be an extremely uncommon transmission route for HIV. We present a review of available evidence on the oral-genital transmission of HIV and analyse the factors that act to protect oral tissues from infection, thereby reducing the risk of HIV transmission by oral sex. Among these factors we highlight the levels of HIV RNA in saliva, presence of fewer CD4+ target cells, presence of IgA antibodies in saliva, presence of other infections in the oral cavity and the endogenous salivary antiviral factors lysozyme, defensins, thrombospondin and secretory leucocyte protease inhibitor (SLPI).

Genetic characterization of diverse HIV-1 strains in an immigrant population living in New York City

New York City (NYC) is one of the original foci of the HIV-1 epidemic and has a greater number of AIDS cases than any other city in the United States. NYC also hosts the highest number of immigrants among the nation's cities: more than 2 million among a total population of 8 million. Such a high rate of immigration could act as a potential source for introducing and disseminating novel HIV-1 strains into the United States. Our current study focuses on the genetic characterization of HIV-1 strains circulating in an immigrant population in NYC. Of the 505 HIV-1-positive specimens obtained, 196 were available for viral sequencing from the C2 to V3 region of env. Phylogenetic analysis using maximum-likelihood and neighbor-joining methods demonstrated that non-B subtypes and circulating recombinant forms (CRFs) accounted for 43.4% (85 of 196 cases), whereas the remaining 56.6% (111 of 196) cases had viral variants similar to the typical North American subtype B virus. Of those non-B subtypes and CRFs, subtype A and CRF02 dominated (63.5% combined); other subtypes, including C, D, F1, G, CRF01_AE, and CRF06_cpx, were also detected. Two HIV-1 sequences do not cluster with any known subtypes or CRFs. Furthermore, the distribution of non-B subtypes and CRFs was consistent with the countries of origin, suggesting that many of the study subjects were likely infected in their home country before they entered the United States. Subtype B viruses identified in the immigrant population showed no significant differences from the typical North American B subtype, however, indicating that a significant proportion of the immigrants must have been infected after they came to the United States. Public health officials and physicians should be aware of the growing genetic diversity of HIV-1 in this country, particularly in areas with sizable immigrant populations.

Virus fitness: concept, quantification, and application to HIV population dynamics

Viral fitness has been broadly studied during the past three decades, mainly to test evolutionary models and population theories difficult to analyze and interpret with more complex organisms. More recent studies, however, are focused in the role of fitness on viral transmission, pathogenesis, and drug resistance. Here, we used human immunodeficiency virus (HIV) as one of the most relevant models to evaluate the importance of viral quasispecies and fitness in HIV evolution, population dynamics, disease progression, and potential clinical implications.

Role of human beta-defensins in HIV infection

Mechanisms of resistance to HIV-1 infection in the human oral cavity are incompletely understood. While salivary components have been implicated in protection, there is growing evidence that human beta-defensins (hBDs), originating in oral epithelial cells, may be playing an important role in the prevention of HIV infection. New antiviral, chemotactic, and immunosurveillance properties are being attributed to hBDs, which are small cationic antimicrobial innate response molecules expressed in mucosal epithelium. Inducible hBDs are always expressed in normal oral epithelium, a property not shared by other mucosal barriers. Data reviewed in this paper demonstrate that: (1) HIV-1 X4 and R5 phenotypes induce hBD-2 and -3 mRNA in normal human oral epithelial cells; (2) hBD-2 and -3 inhibit HIV-1 infection by both viral strains, with greater activity against X4 viruses; and (3) this inhibition is due to a direct interaction with virions and through modulation of the CXCR4 co-receptor. These properties may be exploited as strategies for mucosal protection against HIV-1 transmission.

The HIV-1 clade C promoter is particularly well adapted to replication in the gut in primary infection

OBJECTIVE

Coinfection of rhesus macaques with human/simian immunodeficiency virus chimeras harbouring the minimal core-promoter/enhancer elements from HIV-1 clade B, C and E viral prototypes (STR-B, STR-C and STR-E) revealed a remarkable dichotomy in terms of spatio-temporal viral replication. The clade C chimera (STR-C) predominated in primary infection. The present study was aimed at identifying the origin of STR-C plasma viraemia at this infection phase.

DESIGN

By competing isogenic viruses differing only in their promoters, it was possible to identify subtle phenotypical differences in viral replication kinetics and compartmentalization in vivo.

METHODS

Two rhesus macaques were coinfected by the three STR chimeras and the relative colonization of different compartments, particularly blood and stool, was determined for each chimera. Moreover, growth competition experiments in thymic histocultures enriched in interleukin (IL)-7 were performed and relative percentages of chimeras were estimated in supernatants and thymocytes lysates at different time points.

RESULTS

It is demonstrated here that at the peak of primary infection, preferential replication of STR-C was supported by the gut-associated lymphoid tissue (GALT), an IL-7 rich microenvironment. This was shown by the correlation of the RNA viral genotype in blood and stools, compartments directly draining virions from the GALT. Thymic histocultures confirmed that replication of STR-C is particularly susceptible to this cytokine, compared to its STR-B and STR-E counterparts.

CONCLUSIONS

These data show that the GALT cytokine network may well favour HIV-1 clade C replication during primary infection. This could result in enhanced transmission.

A diversidade do HIV-1: uma ferramenta para o estudo da pandemia

Uma das características mais marcantes do HIV-1 é a imensa diversidade observada entre as cepas que compõem a pandemia de HIV/AIDS. Na última década, a classificação das variantes do vírus em grupos, subtipos e formas recombinantes circulantes (CRF) e a observação de padrões específicos de mutação têm provado serem ferramentas poderosas para os estudos da dinâmica molecular do vírus. O acompanhamento da distribuição mundial da diversidade do HIV-1 tem sido empregado, por exemplo, em programas de vigilância epidemiológica, bem como na reconstrução da história de epidemias regionais. Além disto, a observação de padrões específicos de distribuição espacial do vírus sugere a existência de diferenças na patogenia e transmissibilidade entre os diversos subtipos. A análise molecular das seqüências do vírus também permite a estimativa do tempo de divergência entre as variantes e das forças dinâmicas que modelam as árvores filogenéticas.

Absence of HIV-associated nephropathy in Ethiopians

BACKGROUND

Population-based epidemiological surveys in several countries have shown approximately 10- to 15-fold increased susceptibility to human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) for populations of recent African ancestry. Accordingly, we sought to determine whether a similar or different pattern of susceptibility was evident among Ethiopians followed up in an HIV clinic in Israel.

METHODS

One hundred seventy-six consecutive patients (126 Ethiopians, 50 non-Ethiopian Israelis) followed up at the HIV clinic of Rambam Medical Center in northern Israel were examined for the presence of proteinuria and/or decreased glomerular filtration rate. HIV viral load, CD4 count, and treatment modality also were determined.

RESULTS

Overall, 73% of patients were treated with highly active antiretroviral therapy, and there was no difference between Ethiopians and non-Ethiopian Israelis in this regard. Mean CD4 count in Ethiopians was 288 +/- 140/microL, significantly less than the corresponding CD4 count of 398 +/- 190/microL for non-Ethiopian Israelis. Mean viral loads were greater in Ethiopians compared with non-Ethiopian Israelis. None of 176 HIV-infected patients fulfilled clinical criteria for HIVAN as delineated in this study.

CONCLUSION

HIV-infected individuals of Ethiopian descent have a level of susceptibility to HIVAN similar to that of non-Ethiopian Israelis, which is strikingly less than that reported for other populations for recent African ancestry. This does not appear to be attributable to differences in HIV infection control or viral subtype and most likely represents population-based differences in host genetic factors. This finding emphasizes the importance of avoiding generalizations with respect to phylogeographic ancestry in disease-susceptibility studies.

Cell reservoirs in lymph nodes infected with HIV-1 subtype E differ from subtype B: identification by combined in situ polymerase chain reaction and immunohistochemistry

In Thailand, the predominant HIV subtype is E, rather than subtype B as in North America and Europe. Subtype E has the ability to replicate in vitro in Langerhans cells. We hypothesized that this cell type might constitute a reservoir for the HIV virus in infected lymph nodes. We examined lymph nodes from 25 HIV-1 subtype E-infected patients to determine the immunophenotype of HIV-1-infected cells, their numbers and their distribution. The presence of HIV was detected either by in situ reverse transcriptase-polymerase chain reaction or immunoperoxidase. Cell identity was determined by double labelling using alkaline phosphatase-based immunohistochemistry. The majority of HIV-infected cells in the lymph nodes were Langerhans cells (CD1a+S100+) and Langerhans-related dendritic cells (p55+S100+). These cells were located in the paracortical areas of lymph nodes, with a few cells scattered at the edges of germinal centers, but were absent from germinal centers themselves, in contrast to the reported distribution of subtype B virus. In addition, multinucleated giant cells were significantly more common in HIV-infected nodes (64%) compared to controls (4%) (P=0.00002). In conclusion, Langerhans histiocytes and related cells are reservoirs for HIV subtype E in lymph nodes. Disrupting the pathway of infection of Langerhans cells and related cells may be a viable strategy to interfere with transmission of HIV subtype E.

HIV-1 co-infection, superinfection and recombination

As the human immunodeficiency virus (HIV) pandemic progresses, an increasing number of recombinant viruses have been identified and in many geographical regions they are now the predominating strain. These recombinants are formed when an individual has acquired a co-infection or superinfection with more than one HIV-1 strain or subtype. Thus, dually infected individuals provide opportunities for studying HIV recombinants and viral interactions between infecting strains in vivo. The possible epidemiological, clinical and therapeutic implications of dual infections and recombination are many. Recombination may result in the emergence of more pathogenic and virulent HIV strains with altered fitness, tropism, and resistance to multiple drugs, and may hamper the development of subtype-based vaccines. This review is aimed at providing a more thorough understanding of dual infections (both co-infection and super-infection) and the possible consequences of the emergence of recombinant HIV-1 strains.

HIV-1 subtype C dissemination in southern Brazil

OBJECTIVES

To describe the molecular and epidemiological profile of HIV-1 in patients followed at the University Hospital of Rio Grande, Brazil.

DESIGN AND METHODS

A cross-sectional study was conducted from September to December 2002. Plasma viral RNA of 85 patients was extracted and protease and reverse transcriptase genes were polymerase chain reaction-amplified and sequenced. Sequences were subtyped and examined to antiretroviral resistance mutations. Laboratory data and past history of antiretroviral treatment were also collected.

RESULTS

Most viruses were either subtype B (42%) or subtype C (45%). No risk behaviour, sexual orientation or laboratory parameter was associated with any specific subtype, but subtype C tended to be more frequently found in women (P = 0.06). The prevalence of subtype C has increased over the HIV/AIDS epidemic, accounting for almost 60% of cases diagnosed in 2002. Intra-subtype genetic distances were smaller in subtype C than in subtype B, suggesting a more recent introduction of the former in the epidemic. Of patients under treatment, 60% had at least one antiretroviral drug resistance mutation, but no mutation was specifically associated with any HIV-1 subtype. Only one resistance mutation each was found in drug-naive patients with subtypes B and C.

CONCLUSION

Despite the fact that subtype C appeared in southern Brazil more recently than subtype B, it is now the predominant strain in Rio Grande. The epidemic spread of subtype C could be taking place in Brazil, and possibly in south America, a phenomenon similar to that seen in other countries where this subtype is now totally dominant.