Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus.

Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM) exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX) transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU), we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic "signatures" within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission.

Optimizing Pre-Exposure Antiretroviral Prophylaxis Adherence in Men Who Have Sex with Men: Results of a Pilot Randomized Controlled Trial of "Life-Steps for PrEP".

Antiretroviral pre-exposure prophylaxis (PrEP) has been demonstrated to decrease HIV acquisition in multiple efficacy trials, but medication adherence is critical, and was suboptimal in several studies. Fifty HIV-uninfected at risk men who have sex with men (MSM) were randomized to a cognitive behavioral intervention condition or a time and session-matched comparison counseling intervention. The experimental intervention entailed four nurse-delivered initial and two booster sessions based on Life-Steps, an ART treatment adherence intervention. The comparison condition provided information and supportive counseling. The primary analyses compared adherence (Wisepill and tenofovir plasma levels) at 3 and 6 months. Fifty-eight MSM were screened to enroll 50 participants. Median age was 38.2 years old, 86% were white; 64% had completed college. Wisepill adherence was high in both groups, and not statistically different. Plasma tenofovir levels were significantly higher in the intervention group at 6 months using mean substitution analysis (i.e., computing missing variables) (p = 0.037), however, in the completer analyses (i.e., using only those completing all study visits), there were no statistically significant differences between randomization conditions. Medication adherence was high across a cognitive-behavioral (Life-Steps) and time-matched counseling intervention for PrEP adherence, with some evidence suggesting superiority of Life-Steps in this pilot RCT. Further evaluation in a fully powered efficacy trial is warranted to assess the robustness of this intervention.

"Life-Steps" for PrEP Adherence: Demonstration of a CBT-Based Intervention to Increase Adherence to Preexposure Prophylaxis (PrEP) Medication Among Sexual-Minority Men at High Risk for HIV Acquisition.

One dramatic advance in human immunodeficiency virus (HIV) prevention efforts has been the prescription of medications typically used for HIV treatment as prophylaxis against acquiring HIV. As a preventative agent, this practice is referred to as "preexposure prophylaxis" (PrEP). The U.S. Federal Drug Administration approved daily PrEP for adults at risk for HIV who do not consistently use condoms during sex with HIV-infected or unknown-status partners. In this paper, we describe a cognitive-behavioral therapy (CBT) PrEP adherence intervention developed for use in high-risk sexual-minority men in the United States, adapted from "Life-Steps," an evidence-based CBT intervention to promote adherence to HIV treatment. Modules include creating a PrEP dosing schedule, adhering to daily PrEP, problem solving barriers to adherence, and sexual risk-reduction techniques. Supplemented with practical video vignettes, this novel intervention may help to enhance the clinical practice of health care providers in outpatient settings to increase PrEP adherence in sexual-minority men.

Whole genome deep sequencing of HIV-1 reveals the impact of early minor variants upon immune recognition during acute infection.

Deep sequencing technologies have the potential to transform the study of highly variable viral pathogens by providing a rapid and cost-effective approach to sensitively characterize rapidly evolving viral quasispecies. Here, we report on a high-throughput whole HIV-1 genome deep sequencing platform that combines 454 pyrosequencing with novel assembly and variant detection algorithms. In one subject we combined these genetic data with detailed immunological analyses to comprehensively evaluate viral evolution and immune escape during the acute phase of HIV-1 infection. The majority of early, low frequency mutations represented viral adaptation to host CD8+ T cell responses, evidence of strong immune selection pressure occurring during the early decline from peak viremia. CD8+ T cell responses capable of recognizing these low frequency escape variants coincided with the selection and evolution of more effective secondary HLA-anchor escape mutations. Frequent, and in some cases rapid, reversion of transmitted mutations was also observed across the viral genome. When located within restricted CD8 epitopes these low frequency reverting mutations were sufficient to prime de novo responses to these epitopes, again illustrating the capacity of the immune response to recognize and respond to low frequency variants. More importantly, rapid viral escape from the most immunodominant CD8+ T cell responses coincided with plateauing of the initial viral load decline in this subject, suggestive of a potential link between maintenance of effective, dominant CD8 responses and the degree of early viremia reduction. We conclude that the early control of HIV-1 replication by immunodominant CD8+ T cell responses may be substantially influenced by rapid, low frequency viral adaptations not detected by conventional sequencing approaches, which warrants further investigation. These data support the critical need for vaccine-induced CD8+ T cell responses to target more highly constrained regions of the virus in order to ensure the maintenance of immunodominant CD8 responses and the sustained decline of early viremia.

Femoral neck structural properties are altered in adults with type 1 diabetes.

AIMS: To determine differences in hip geometry in adults with type 1 diabetes (T1D) compared with healthy adults without diabetes. METHODS: In this cross-sectional study, 43 adults with T1D (mean age 56 years, 84 % female, 92 % White, mean duration of diabetes of 39 years, A1c of 7.8 %) and 40 adults without diabetes (mean age 60 years, 80 % female, 77 % white) who had hip dual-energy x-ray absorptiometry (DXA) scans from previous studies were included. Areal bone mineral density (aBMD) and measures of hip structural properties at the narrow neck, intertrochanteric and femoral shaft regions of the left proximal femur were analyzed between adults with T1D and controls using linear models controlled for age, sex, and body mass index. RESULTS: There were no significant differences in DXA-based aBMD at the hip (0.769 ± 0.132 vs. 0.900 ± 0.139 g/cm2, p = 0.07) or femoral neck (0.722 ± 0.116 vs. 0.849 ± 0.114 g/cm2, p = 0.09) regions between adults with T1D and controls. When controlling for age, sex, and BMI, DXA-based aBMD at the hip (0.880 ± 0.022 vs. 0.943 ± 0.020 g/cm2, p = 0.02) and femoral neck (0.750 ± 0.021 vs. 0.812 ± 0.020 g/cm2, p = 0.02) regions were significantly lower in adults with T1D than controls. Cortical thickness was significantly lower in all three hip regions in adults with T1D than in controls (narrow-neck: 0.169 ± 0.005 vs. 0.186 ± 0.005 cm, p = 0.011; intertrochanteric: 0.388 ± 0.013 vs. 0.425 ± 0.012 cm, p = 0.017; femoral shaft: 0.529 ± 0.017 vs. 0.586 ± 0.016 cm, p = 0.006). Moreover, adults with T1D had a smaller cross-sectional area at the narrow-neck (3.06 ± 0.09 vs. 3.32 ± 0.08 cm2, p = 0.015), a higher femoral shaft endocortical diameter (2.23 ± 0.07 vs. 2.02 ± 0.06 cm, p = 0.011), and higher buckling ratios (an indicator of cortical instability) at the intertrochanteric (9.22 ± 0.34 vs. 8.23 ± 0.32, p = 0.016) and femoral shaft (3.32 ± 0.15 vs. 2.89 ± 0.14, p = 0.016) regions. CONCLUSIONS: Adults with T1D have several significant differences in proximal femur morphology compared with controls. These morphological differences may adversely affect the mechanical integrity of the proximal femur, thereby contributing to an increased risk of fracture in the event of a fall.

Street workers and internet escorts: contextual and psychosocial factors surrounding HIV risk behavior among men who engage in sex work with other men.

Sex work has been associated with elevated risk for HIV infection among men who have sex with men (MSM) in many settings. This mixed methods study examined sexual risk among MSM sex workers in Massachusetts, collecting formative data on HIV risk behavior by sex worker type in order to gain a better understanding of how to tailor prevention interventions to this unique and high-risk subgroup of MSM. Two groups of MSM sex workers were recruited between January and March 2008: street workers (n=19) and internet escorts (n=13). Participants completed a semistructured qualitative interview and quantitative psychosocial assessment battery; interviews were conducted until redundancy in responses was achieved. Almost one third (31%) were HIV-infected. The majority of participants (69%) reported at least one episode of unprotected serodiscordant anal sex (either insertive or receptive) with a mean of 10.7 (SD=42.2) male sex partners of an unknown or different HIV serostatus in the past 12 months. Salient findings included: (a) internet sex workers reported being paid substantially more for sex than street sex workers; (b) inconsistent condom use, high rates of unprotected sex, and low rates of HIV status disclosure with sex work partners for both internet and street workers; general perceptions of a lack of trust on the part of sex work partners (i.e., telling them what they want to hear), offers of more money for unprotected sex; (c) contextual differences in risk taking: internet sex workers reported that they are more likely to engage in sexual risk-taking with noncommercial sex partners than sex partners who pay; (d) HIV status and STI history: two street workers became infected in the context of sex work, and 25% of the entire sample had never been tested for sexually transmitted infections (STI); and (e) motivations and reasons for doing sex work, such as the "lucrativeness" of sex work, as a means to obtain drugs, excitement, power, "why not?" attitude, and because social norms modeled this behavior. Study findings can be used to generate hypotheses for designing and providing tailored primary and secondary prevention interventions for this at-risk subgroup of MSM.

Tricks of the trade: sexual health behaviors, the context of HIV risk, and potential prevention intervention strategies for male sex workers.

Sex work is a significant risk for HIV and sexually transmitted infection (STI) among men who have sex with men (MSM); however, there is a dearth of knowledge about how to reduce risk in this group. MSM sex workers (N = 32) completed a semistructured qualitative interview and a close-ended quantitative assessment. Analyses focused on themes relevant to intervention development. Participants reported an average of 46 male sex partners in the prior 12 months; 31% of participants were HIV-infected. Male sex workers frequently used substances during sex and had elevated levels of psychological distress. Qualitative findings suggest that trauma-informed mental health and substance abuse treatment, ready access to HIV/STI testing and treatment and condoms/informational materials, support groups to address isolation/loneliness, skill-building for risk reduction with sex partners, and paid incentives as add-ons to effective behavior change interventions may be valuable intervention components. Targeting consumers of paid/exchanged sex may assist with changing community norms regarding the practice of transactional sex. Multipronged interventions to decrease sexual risk taking among male sex workers would also benefit from addressing the unique socioeconomic and legal needs of this population.