Limits on oral transmission of HIV-1

The Risk of HIV/STDs Infection and Transmission Among Never-Married Male Migrants in China: Is Risk Attributable to Bachelorhood or Migration?

In the context of sex-ratio imbalance and rural-to-urban migration in China, never-married male migrants may become a vulnerable group as well as a bridge population that facilitates HIV/STDs transmission. It is still not clear, however, whether increased HIV/STDs transmission risk can be attributed to bachelorhood, migration, or both. This study identified the contributions of bachelorhood and migration to an increased risk of HIV/STDs infection, as well as the risk of HIV/STDs transmission across populations and regions. Data were from a cross-sectional questionnaire survey, in which 180 never-married non-migrant males in rural areas, 558 never-married male migrants, and 302 married male migrants in urban areas of China were interviewed in 2017. Results showed that never-married male migrants are more likely to engage in commercial sex and unsafe sex than never-married non-migrant males, and their likelihood of engaging in unsafe sex was also higher than married male migrants. Although never-married male migrants were less likely to have multiple sex partners than married male migrants, they were more likely to have multiple sex partners and sex partners from different regions than never-married non-migrant males. These findings indicate that both migration and bachelorhood increase the risk of HIV/STDs infection for never-married male migrants, and migration also increases the risk of HIV/STDs transmission across populations and regions.

Genetic associations of the vitamin D and antiviral pathways with natural resistance to HIV-1 infection are influenced by interpopulation variability

Vitamin D (VitD) may modulate anti-HIV-1 responses modifying the risk to acquire the HIV-1-infection. We performed a nested case-control exploratory study involving 413 individuals; HIV-1-exposed seropositives (cases) and seronegatives (HESN) (controls) from three cohorts: sexually-exposed from Colombia and Italy and parenterally-exposed from Spain. The association and interactions of 139 variants in 9 VitD pathway genes, and in 14 antiviral genes with resistance/susceptibility (R/S) to HIV-1 infection was evaluated. Associations between variants and mRNA levels were also analyzed in the Colombian samples. Variants and haplotypes in genes of VitD and antiviral pathways were associated with R/S, but specific associations were not reproduced in all cohorts. Allelic heterogeneity could explain such inconsistency since the associations found in all cohorts were consistently in the same genes: VDR and RXRA of the VitD pathway genes and in TLR2 and RNASE4. Remarkably, the multi-locus genotypes (interacting variants) observed in genes of VitD and antiviral pathways were present in most HESNs of all cohorts. Finally, HESNs carrying resistance-associated variants had higher levels of VitD in plasma, of VDR mRNA in blood cells, and of ELAFIN and defensins mRNA in the oral mucosa. In conclusion, despite allelic heterogeneity, most likely due to differences in the genetic history of the populations, the associations were locus dependent suggesting that genes of the VitD pathway might act in concert with antiviral genes modulating the resistance phenotype of the HESNs. Although these associations were significant after permutation test, only haplotype results remained statistically significant after Bonferroni test, requiring further replications in larger cohorts and functional analyzes to validate these conclusions.

Innate immunity in HIV-1 infection: epithelial and non-specific host factors of mucosal immunity- a workshop report

The interplay between HIV-1 and epithelial cells represents a critical aspect in mucosal HIV-1 transmission. Epithelial cells lining the oral cavity cover subepithelial tissues, which contain virus-susceptible host cells including CD4(+) T lymphocytes, monocytes/macrophages, and dendritic cells. Oral epithelia are among the sites of first exposure to both cell-free and cell-associated virus HIV-1 through breast-feeding and oral-genital contact. However, oral mucosa is considered to be naturally resistant to HIV-1 transmission. Oral epithelial cells have been shown to play a crucial role in innate host defense. Nevertheless, it is not clear to what degree these local innate immune factors contribute to HIV-1 resistance of the oral mucosa. This review paper addressed the following issues that were discussed at the 7th World Workshop on Oral Health and Disease in AIDS held in Hyderabad, India, during November 6-9, 2014: (i) What is the fate of HIV-1 after interactions with oral epithelial cells?; (ii) What are the keratinocyte and other anti-HIV effector oral factors, and how do they contribute to mucosal protection?; (iii) How can HIV-1 interactions with oral epithelium affect activation and populations of local immune cells?; (iv) How can HIV-1 interactions alter functions of oral epithelial cells?

Increase in HIV Receptors/Co-receptors/α-defensins in Inflamed Human Gingiva

Transmission of HIV-1 through the oral cavity is considered to be a rare event. To identify factors in resistance/susceptibility to oral HIV-1 infection, we analyzed expression in human gingiva of HIV-1 receptors Langerin, DC-SIGN, MR, and GalCer, HIV-1 co-receptors CCCR5, CXCR4, and anti-microbial protein α-defensin-1. Our results show that healthy gingiva is infiltrated with cells expressing all HIV-1 receptors tested; however, there are very few CCR5+ cells and a complete absence of CXCR4+ cells in the lamina propria. In chronic periodontitis (CP), DC-SIGN, MR, CXCR4, and CCR5 increase, but this was accompanied by a ten-fold increase in α-defensin-1 mRNA. The CCR5+ cells were revealed to be T-cells, macrophages, and dermal dendritic cells. Moreover, epithelial expression of GalCer and CXCR4 together was not apical and showed no trend with underlying inflammation. Thus, low expression of HIV-1 co-receptors in health and high expression of α-defensin during CP may comprise endogenous factors that provide protection from oral HIV-1 infection.

Oral Mucosal Immunity and HIV/SIV Infection

Human Immunodeficiency Virus (HIV) transmission through genital and rectal mucosa has led to intensive study of mucosal immune responses to HIV and to the development of a vaccine administered locally. However, HIV transmission through the oral mucosa is a rare event. The oral mucosa represents a physical barrier and contains immunological elements to prevent the invasion of pathogenic organisms. This particular defense differs between micro-compartments represented by the salivary glands, oral mucosa, and palatine tonsils. Secretory immunity of the salivary glands, unique features of cellular structure in the oral mucosa and palatine tonsils, the high rate of oral blood flow, and innate factors in saliva may all contribute to the resistance to HIV/Simian Immunodeficiency Virus (SIV) oral mucosal infection. In the early stage of HIV infection, humoral and cellular immunity and innate immune functions in oral mucosa are maintained. However, these particular immune responses may all be impaired as a result of chronic HIV infection. A better understanding of oral mucosal immune mechanisms should lead to improved prevention of viral and bacterial infections, particularly in immunocompromised persons with Acquired Immune Deficiency Syndrome (AIDS), and to the development of a novel strategy for a mucosal AIDS vaccine, as well as vaccines to combat other oral diseases, such as dental caries and periodontal diseases.

Oral epithelial cells and their interactions with HIV-1

As the AIDS pandemic has continued, our understanding of the events that occur during the entry and infection of conventional, susceptible cells has increased dramatically, leading to the development of control therapies for HIV-infected individuals. However, an ongoing hole in our understanding is how HIV crosses the mucosal barriers to gain access to permissive cells, despite how important this information would be in developing successful vaccines and other preventative measures such as topical anti-HIV microbicides. In particular, our knowledge of the role that epithelial cells of the mucosal surfaces play in infection - both during early phases and throughout the life of an infected individual, is currently hazy at best. However, several studies in recent years suggest that HIV can bind to and traverse these mucosal epithelial cells, providing a reservoir of infection that can subsequently infect underlying permissive cells. Despite this interaction with epithelial cells, evidence suggests HIV-1 does not productively infect these cells, although they are capable of transferring surface-bound and transcytosed virus to other, permissive cells. Further, there appear to be key differences between adult and infant epithelial cells in the degree to which HIV can transcytose and infect the epithelium. Thus, it is clear that, whilst not primary targets for infection and virus replication, epithelial cells play an important role in the infection cycle and improving our understanding of their interactions with HIV could potentially provide key insights necessary to develop effective preventative therapies.

Oral and vaginal epithelial cell lines bind and transfer cell-free infectious HIV-1 to permissive cells but are not productively infected

The majority of HIV-1 infections worldwide are acquired via mucosal surfaces. However, unlike the vaginal mucosa, the issue of whether the oral mucosa can act as a portal of entry for HIV-1 infection remains controversial. To address potential differences with regard to the fate of HIV-1 after exposure to oral and vaginal epithelium, we utilized two epithelial cell lines representative of buccal (TR146) and pharyngeal (FaDu) sites of the oral cavity and compared them with a cell line derived from vaginal epithelium (A431) in order to determine (i) HIV-1 receptor gene and protein expression, (ii) whether HIV-1 genome integration into epithelial cells occurs, (iii) whether productive viral infection ensues, and (iv) whether infectious virus can be transferred to permissive cells. Using flow cytometry to measure captured virus by HIV-1 gp120 protein detection and western blot to detect HIV-1 p24 gag protein, we demonstrate that buccal, pharyngeal and vaginal epithelial cells capture CXCR4- and CCR5-utilising virus, probably via non-canonical receptors. Both oral and vaginal epithelial cells are able to transfer infectious virus to permissive cells either directly through cell-cell attachment or via transcytosis of HIV-1 across epithelial cells. However, HIV-1 integration, as measured by real-time PCR and presence of early gene mRNA transcripts and de novo protein production were not detected in either epithelial cell type. Importantly, both oral and vaginal epithelial cells were able to support integration and productive infection if HIV-1 entered via the endocytic pathway driven by VSV-G. Our data demonstrate that under normal conditions productive HIV-1 infection of epithelial cells leading to progeny virion production is unlikely, but that epithelial cells can act as mediators of systemic viral dissemination through attachment and transfer of HIV-1 to permissive cells.

Impact of mucosal inflammation on oral simian immunodeficiency virus transmission

Mucosal tissues are the primary route of transmission for most respiratory and sexually transmitted diseases, including human immunodeficiency virus (HIV). There is epidemiological evidence that genital mucosal inflammation leads to enhanced HIV type 1 (HIV-1) transmission. The objective of this study was to assess the influence of periodontal inflammation on oral HIV transmission using a nonhuman primate model of teeth ligature-induced periodontitis. Simian immunodeficiency virus (SIV) was nontraumatically applied to the gingiva after moderate gingivitis was identified through clinical and immunologic analyses (presence of inflammatory cytokines). Overall oral SIV infection rates were similar in the gingivitis-induced and control groups (5 infections following 12 SIV administrations for each), although more macaques were infected with multiple viral variants in the gingivitis group. SIV infection also affected the levels of antiviral and inflammatory cytokines in the gingival crevicular fluid, and a synergistic effect was observed, with alpha interferon and interferon-inducible protein 10 undergoing significant elevations following SIV infection in macaques with gingivitis compared to controls. These increases in antiviral and inflammatory immune modulators in the SIV-infected gingivitis macaques could also be observed in blood plasma, although the effects at both compartments were generally restricted to the acute phase of the infection. In conclusion, while moderate gingivitis was not associated with increased susceptibility to oral SIV infection, it resulted in elevated levels of cytokines in the oral mucosa and plasma of the SIV-infected macaques. These findings suggest a synergy between mucosal inflammation and SIV infection, creating an immune milieu that impacts the early stages of the SIV infection with potential implications for long-term pathogenesis.

Determinants of protection among HIV‐exposed seronegative persons: an overview

Both clinical experience and a growing medical literature indicate that some persons who have been exposed to human immunodeficiency virus (HIV) infection remain uninfected. Although in some instances this may represent good fortune, cohorts of uninfected persons have been reported who are considered at high risk for infection. In these cohorts a variety of characteristics have been proposed as mediating protection, but to date only the 32–base pair deletion in the chemokine (C‐C motif) receptor 5 gene, which results in complete failure of cell surface expression of this coreceptor, has been associated with high‐level protection from HIV infection. With this in mind, there are probably many other factors that may individually or in combination provide some level of protection from acquisition of HIV infection. Because some of these factors are probably incompletely protective or inconsistently active, identifying them with confidence will be difficult. Nonetheless, clarifying the determinants of protection against HIV infection is a high priority that will require careful selection of high‐risk uninfected cohorts, who should undergo targeted studies of plausible mediators and broad screening for unexpected determinants of protection.

Characterization of SIV in the oral cavity and in vitro inhibition of SIV by rhesus macaque saliva

Human immunodeficiency virus (HIV) infections are rarely acquired via an oral route in adults. Previous studies have shown that human whole saliva inhibits HIV infection in vitro, and multiple factors present in human saliva have been shown to contribute to this antiviral activity. Despite the widespread use of simian immunodeficiency virus (SIV)-infected rhesus macaques as models for HIV pathogenesis and transmission, few studies have monitored SIV in the oral cavity of infected rhesus macaques and evaluated the viral inhibitory capacity of macaque saliva. Utilizing a cohort of rhesus macaques infected with SIV(Mac251), we monitored virus levels and genotypic diversity in the saliva throughout the course of the disease; findings were similar to previous observations in HIV-infected humans. An in vitro infectivity assay was utilized to measure inhibition of HIV/SIV infection by normal human and rhesus macaque whole saliva. Both human and macaque saliva were capable of inhibiting HIV and SIV infection. The inhibitory capacity of saliva samples collected from a cohort of animals postinfection with SIV increased over the course of disease, coincident with the development of SIV-specific antibodies in the saliva. These findings suggest that both innate and adaptive factors contribute to inhibition of SIV by whole macaque saliva. This work also demonstrates that SIV-infected rhesus macaques provide a relevant model to examine the innate and adaptive immune responses that inhibit HIV/SIV in the oral cavity.

Effects of structural intervention on increasing condom availability and reducing risky sexual behaviours in gay bathhouse attendees

The study purpose was to evaluate the effectiveness of a structural intervention in reducing unprotected sexual behaviours, increasing condom accessibility and their relationship to the prevalence of HIV infection and sexually transmitted infections (STIs) in gay bathhouse attendees. A quasi-experimental study with a non-equivalent control group for comparison was conducted at nine gay bathhouses in Taiwan from 2004 to 2006. A structural intervention designed to increase condom distribution and accessibility inside the bathhouses was implemented at one bathhouse in each city. Bathhouse attendees were invited to complete a questionnaire and to be screened for HIV infection and STIs. Of 632 study participants, 270 were surveyed six months after the intervention was conducted. At the time of follow-up after controlling for baseline data, patrons attending bathhouses for which intervention was performed were more likely to report accessing condoms inside bathhouses than those attending control bathhouses (92.6% versus 81.3%, P = 0.016), and condoms were more likely to be available at the reception desk of the bathhouse entrance (87.5% in intervention bathhouses versus 69.4% in control, P = 0.047). In a multivariate analysis adjusted for age, access to condoms inside bathhouses (adjusted odds ratio (AOR): 4.35; 95% confidence interval (CI): 1.48-12.78) and attendance at bathhouses with intervention (AOR: 2.07; 95% CI: 1.07-3.97) were independently associated with consistent condom use during anal intercourse. There were no significant differences in the prevalences of HIV infection and STIs at the six-month follow-up. Bathhouses with structural intervention were associated with consistent condom use during anal intercourse among bathhouse patrons. Our findings highlight the importance of extension of condom distribution inside the bathhouses to increase condom use among bathhouse patrons.

HIV type 1 fails to trigger innate immune factor synthesis in differentiated oral epithelium

The oral mucosa is relatively resistant to human immunodeficiency virus type 1 (HIV-1) transmission. The mechanisms contributing to this resistance remain incompletely understood, but may include HIV-induced synthesis of innate immune factors. We used fully differentiated oral epithelium as a surrogate for the oral mucosa in vivo, exposed it to X4- and R5-tropic HIV-1 in culture, and quantified mRNA expression of six innate immune factors. Neither virus increased expression of human beta defensin 2 (hBD-2) mRNA over supernatants from uninfected lymphoblast controls. HIV-1 also failed to induce mRNA of four additional innate immunity-related genes. Similar results were obtained with oral monolayer epithelial cells. Interestingly, the X4-tropic virus inhibited mRNA expression of hBD-2, and of three of the other factors, at higher dosages in the differentiated oral epithelium but not the monolayers. The failure of HIV-1 to induce innate immune factors in the differentiated epithelium was not due to a lack of tissue penetration, as we detected fluorescence-tagged virions up to 30 mum deep from the apical surface. HIV-1 does not trigger de novo innate immune factor synthesis in oral epithelium, pointing to the role of a constitutive innate immunity for protection against HIV-1 in the oral cavity.

Immunocytochemical localization of MG1 mucin in human bulbourethral glands

Salivary mucins MG1 and MG2 have been found in the oral cavity where they perform several functions such as the formation of the mucous layer covering the oral mucosa and teeth. Recent studies have demonstrated their presence in other organs and tissues. The aim of this study was to determine their expression in human bulbourethral (Cowper's) glands. Normal bulbourethral glands were obtained at surgery and fixed in a mixture of 1% paraformaldehyde-1.25% glutaraldehyde in 0.1 M cacodylate buffer and embedded in Epon resin. Thin sections were labeled with rabbit antibodies to MG1 or to an N-terminal synthetic peptide of MG2, followed by gold-labeled goat anti-rabbit IgG. The granules of all mucous cells were intensely reactive with anti-MG1, whereas no labeling was detected for MG2. These results indicate that MG1 is not exclusively a salivary component and furthermore show that bulbourethral glands represent a significant source of the MG1 detected in human seminal plasma.

Preventing sexual transmission of HIV

The risk of human immunodeficiency virus (HIV) transmission during sexual activity is dependent on the infectivity of the HIV-positive individual and the susceptibility of the uninfected partner. HIV is most often transmitted during periods of high HIV load, but factors such as the type of sexual activity and the innate and genetic defenses of the uninfected partner exert a strong influence on the risk of transmission. Certain factors, such as coinfection with other sexually transmitted diseases or the presence of genital lesions in either sexual partner, amplify the risk of transmission that is predicted on the basis of sexual contact alone. In the absence of more-reliable options, such as a vaccine, factors that define HIV infectivity and susceptibility and factors that amplify the risk of HIV transmission, may serve as critical targets for containment of the HIV epidemic.

Circuit parties: sexual behaviors and HIV disclosure practices among men who have sex with men at the White Party, Palm Springs, California, 2003

The syphilis epidemic among men who have sex with men (MSM) in major US cities and concomitant increases in high-risk sexual behavior, have raised concerns of increased HIV transmission in this population. Therefore, to provide information for health promotion and disease awareness efforts, we investigated sexual behaviors, partner selection preferences and HIV serostatus disclosure practices of MSM at the White Party in Palm Springs, California. Circuit party attendees reported engaging in unprotected anal sex, however, a high proportion reported disclosing their HIV status. These findings suggest that some gay men are serosorting as a risk reduction strategy or implementing sexual risk reduction strategies to protect themselves and their partners. In our study, HIV-negative men were nine times more likely to report a preference for a seroconcordant sexual partner. The self-protecting attitudes of HIV-negative men in our sample outweighed the partner-protecting attitudes of HIV-positive men. This suggests that prevention interventions focusing on HIV-positive persons are warranted.

Poor educational attainment and sexually transmitted infections associated with positive HIV serostatus among female in-patient substance abusers in Trinidad and Tobago

Female crack cocaine users are at high risk for HIV infection. Data from 121 female substance abusers admitted to an all-female rehabilitation center in Trinidad and Tobago between 1996 and 2002 were reviewed retrospectively to determine human immunodeficiency virus (HIV) seroprevalence and associated risk factors. HIV seroprevalence was 19.8%, which is six times higher than in the general population. The univariate analysis identified the following factors associated with HIV infection: poor educational attainment, history of a sexually transmitted infection (STI), and use of crack cocaine. In the multivariate analysis, only poor educational attainment and history of an STI were independently associated with HIV seroprevalence. Female substance abusers, especially female crack cocaine users, are at high risk of acquiring and transmitting the HIV virus. To reduce risk of HIV infection, rehabilitation programs should address risky sexual behaviors and screen for STIs, and they also should improve educational attainment, develop skills, and provide vocational training.

Oral mucosal expression of HIV-1 receptors, co-receptors, and alpha-defensins: tableau of resistance or susceptibility to HIV infection?

The basic premise of whether transmission of HIV-1 through the oral mucosa actually occurs, and through what route, is a topic of intense interest. Our work has focused on HIV-1 receptors/co-receptors and alpha-defensin-1 in situ in human gingiva. Regardless of HIV-1 infection, the role that C-type lectin receptors might play in periodontal pathogenesis is of great interest. We have shown that the gingival lamina propria, when inflamed, becomes increasingly infiltrated with DC-SIGN+MR+ dermal dendritic cells (DDCs), while the inflamed epithelium shows a decrease in Langerin+ Langerhans cells (LCs). Moreover, DDCs and LCs contribute to the mature CD83+ DC pool in situ, and form immune conjugates with CD4+ T-cells in the lamina propria (Jotwani and Cutler, 2003). This raises the intriguing possibility that oral mucosal DCs may be involved in HIV-1 transfer to T-cells in situ. However, this possibility is tendered by the challenges faced by the virus in gaining access to oral mucosal immune cells, including their ability to survive the salivary defenses, cross the mucosal barrier, resist inactivation by alpha-defensins, and overcome the paucity of co-receptor CCR5 in (healthy) oral mucosa (i.e., required for productive infection [Jotwani et al., 2004]). To date, there is little evidence of direct infection by HIV-1 of oral mucosal DCs/T cells and other cells in situ. Abbreviations used in this paper: CP, chronic periodontitis; CCR5, chemokine receptor 5; CXCR4, C-X-C receptor 4; DCs, dendritic cells; DC-SIGN, DC-specific ICAM-3 grabbing non-integrin; DDC, dermal dendritic cells; LCs, Langerhans cells; LP, lamina propria; MR, mannose receptor.

Relationship of HIV RNA and cytokines in saliva from HIV-infected individuals

We measured levels of six cytokines and human immunodeficiency virus (HIV) RNA in saliva from HIV-seropositive individuals and compared salivary cytokine levels in HIV-seropositives and seronegatives. All of the six tested cytokines were detected in saliva although interleukin-1beta, interferon-gamma and interleukin-10 were detected more frequently (90%, 68% and 61% of samples, respectively) than interleukin-6, tumor necrosis factor-alpha and tumor necrosis factor-alpha receptor II (2-17%). There was no significant association between cytokine levels in saliva and plasma suggesting that cytokines were produced locally. Interferon-gamma levels were significantly higher in saliva from HIV-seropositives when compared to seronegatives while interleukin-10 levels were lower in seropositive saliva. Interleukin-10 levels were higher in individuals with low CD4 counts in the seropositive group. HIV RNA was detected in 29% of saliva samples from seropositives and there was a significant correlation between saliva and plasma HIV RNA levels. However, HIV RNA levels in saliva were not significantly associated with any of the saliva or plasma cytokine levels or with CD4 cell numbers. This study shows no association between inflammatory cytokine levels and HIV levels in saliva and suggests that saliva HIV levels are more influenced by blood HIV RNA levels than oral inflammation.

Human immunodeficiency virus type 1 stimulates the expression and production of secretory leukocyte protease inhibitor (SLPI) in oral epithelial cells: a role for SLPI in innate mucosal immunity

The innate immune response is a key barrier against pathogenic microorganisms such as human immunodeficiency virus type 1 (HIV-1). Because HIV-1 is rarely transmitted orally, we hypothesized that oral epithelial cells participate in the innate immune defense against this virus. We further hypothesized that secretory leukocyte protease inhibitor (SLPI), a 12-kDa mucosal antiviral protein, is a component of the host immune response to this virus. Here we demonstrated constitutive expression and production of SLPI in immortalized human oral keratinocytes. Brief exposure of cells to HIV-1 BaL and HXB2 significantly increased SLPI mRNA and protein production compared to that in mock-exposed cells (P < 0.01), as evaluated by real-time quantitative reverse transcription-PCR and enzyme-linked immunosorbent assay. HIV-1-mediated stimulation of SLPI occurred at the transcriptional level, was dose and time dependent, was elicited by heat-inactivated and infectious viruses, and did not depend on cellular infection. Experiments with purified retroviral proteins showed that the stimulatory effect was induced specifically by external envelope glycoproteins from HIV-1 and simian immunodeficiency virus. SLPI responsiveness to HIV-1 was also observed in an unrelated oral epithelial cell line and in normal (nonimmortalized) human oral epithelial cells isolated from healthy uninfected gingival tissues. In this first report of SLPI regulation by HIV-1, we show that the expression and production of the antimicrobial and anti-inflammatory protein can be stimulated in oral epithelial cells by the virus through interactions with gp120 in the absence of direct infection. These findings indicate that SLPI is a component of the oral mucosal response to HIV-1.

Envelope diversity, coreceptor usage and syncytium-inducing phenotype of HIV-1 variants in saliva and blood during primary infection

OBJECTIVE

To determine whether oral fluids can serve as a model for studying HIV-1 shedding, we compared the genetic diversity, coreceptor use, and syncytium-inducing (SI) phenotype of viral variants in saliva and blood during primary HIV-1 infection.

DESIGN

Observational cross-sectional cohort study.

METHODS

Blood plasma and saliva were sampled from 17 men early in primary HIV-1 infection. Viral diversity, predicted X4/R5 genotype and SI phenotype in samples were determined by heteroduplex tracking assays (HTAs) targeting the V1/V2 and V3 gp120 regions, sequence analyses and MT-2 cell assay.

RESULTS

Identical or very similar HTA banding and deduced amino acid sequence patterns in the V1/V2 and V3-encoding regions were observed between paired fluids of each subject. As assessed by V1/V2 HTA, 10 subjects had a single major viral variant and seven subjects exhibited multiple yet highly related variants. Two subjects had V1/V2 variants in blood that were identical to saliva but present in different relative abundances. A sexual transmission pair exhibited genetically dissimilar variants, suggesting transmission of a minor variant or rapid evolution during initial viremia. All subjects harbored R5 non-SI variants.

CONCLUSIONS

Relatively homogenous viral populations detected in plasma and saliva prior to seroconversion suggests that HIV-1 is disseminated to oral fluids early in infection and reflects the quasispecies in blood. These findings suggest that the oral cavity may serve as an easily accessible surrogate model for studying the dynamics of HIV-1 shedding at mucosal sites.

Continued high risk behaviors in HIV infected drug abusers

To characterize current risk behaviors of HIV drug abusers in the highly active antiretroviral therapy (HAART) era, socio-demographic, medical and behavioral information were obtained and immune measurements determined. High-risk sexual practices were prevalent. Participants diagnosed before 1995 were 6 times more likely to have unprotected sex with HIV+ partners (p = 0.05) and 11 times more likely to use contaminated needles (p = 0.05) than participants with later diagnosis. Consistent condom use was reported by only 7% of the cohort. Many (43%) of the participants reported multiple HIV+ and HIV- concurrent partners. Most (65%), particularly women (OR = 3, p = 0.02), did so for drugs or money. Despite detectable viral loads, 36% reported unprotected anal sex. Antiretroviral-treated men, compared to non-treated, tended to have unprotected anal sex (OR = 2, p = 0.07). The continued high-risk behaviors of HIV drug users, particularly those diagnosed before 1995 and/or on antiretroviral therapy, indicates an urgent need for new public health strategies.