Higher concentration of HIV RNA in rectal mucosa secretions than in blood and seminal plasma, among men who have sex with men, independent of antiretroviral therapy

Human Immunodeficiency Virus Type 1 RNA Levels in Rectal and Seminal Compartments After Switching to Long-Acting Cabotegravir Plus Rilpivirine: A Longitudinal Study

Human immunodeficiency virus type 1 RNA levels were longitudinally evaluated in 211 rectal and 152 seminal samples from 12 virologically suppressed participants switching to monthly long-acting cabotegravir plus rilpivirine or continuing with daily dolutegravir-abacavir-lamivudine. Maintenance of viral suppression in rectal and seminal compartments was comparable, and blips occurred with similar frequency with both treatment regimens.

CLINICAL TRIALS REGISTRATION

NCT02938520.

Rectal and seminal HIV-1 RNA decay towards virological suppression in infected MSM initiating dolutegravir/abacavir/lamivudine

BACKGROUND

The time at which the protective effect of starting ART is achieved in male rectal and genital reservoirs is not clearly established.

OBJECTIVES

To quantify HIV-1 RNA decay towards virological suppression in rectal mucosa and semen in MSM starting dolutegravir/abacavir/lamivudine (DTG/ABC/3TC).

METHODS

A longitudinal cohort study of ART-naive HIV-positive MSM was performed. HIV-1 RNA was quantified in rectal mucosa and seminal plasma samples at day 1 of ART initiation (baseline) and every 4 weeks until week 20 (w20; all participants) and week 64 (w64; 6 of 12 participants).

RESULTS

Twelve MSM, with median (IQR) age 36 (33-40) years and baseline CD4+ count 449 (411-503) cells/mm3, were included. At baseline, HIV-1 RNA was detectable in all plasma and seminal samples and 10/12 rectal samples. All participants achieved plasma virological suppression by w20, whereas HIV-1 RNA was detectable in 42% and 50% of seminal and rectal samples, respectively. At w64, HIV-1 RNA was detectable in 1/6 seminal and 1/6 rectal samples. A relationship of baseline seminal and rectal HIV-1 RNA levels with viral shedding in reservoirs (HIV-1 RNA >200 copies/mL or copies/swab) was found. In addition, a significant association of baseline plasma viral load with time to rectal HIV-1 RNA <200 copies/swab was found (P=0.025).

CONCLUSIONS

Viral decay after initiating DTG/ABC/3TC is slower in rectal mucosa and semen than in plasma. Approximately half of patients achieved undetectable HIV-1 RNA levels in rectal and genital secretions at w20 and in some patients viral shedding persisted for up to 1 year. Initial plasma viral load influences time to rectal suppression.

Genital Shedding of Human Immunodeficiency Virus Type-1 (HIV) When Antiretroviral Therapy Suppresses HIV Replication in the Plasma

BACKGROUND

During antiretroviral treatment (ART) with plasma HIV RNA below the limit of quantification, HIV RNA can be detected in genital or rectal secretions, termed discordant shedding (DS). We hypothesized that proliferating cells produce virions without HIV replication.

METHODS

ART-naive Peruvians initiating ART were observed for DS over 2 years. HIV env and pol genomes were amplified from DS. Antiretrovirals and cytokines/chemokines concentrations were compared at DS and control time points.

RESULTS

Eighty-two participants had ART suppression. DS was detected in 24/82 (29%) participants: 13/253 (5%) cervicovaginal lavages, 20/322 (6%) seminal plasmas, and 6/85 (7%) rectal secretions. HIV RNA in DS specimens was near the limit of quantification and not reproducible. HIV DNA was detected in 6/13 (46%) DS cervicovaginal lavages at low levels. Following DNase treatment, 5/39 DS specimens yielded HIV sequences, all without increased genetic distances. Women with and without DS had similar plasma antiretroviral levels and DS in 1 woman was associated with inflammation.

CONCLUSIONS

HIV RNA and DNA sequences and therapeutic antiretroviral plasma levels did not support HIV replication as the cause of DS from the genital tract. Rather, our findings infer that HIV RNA is shed due to proliferation of infected cells with virion production.

Rapid Collection of Human Rectal Secretions Using OriCol Devices Is Suitable for Measurement of Mucosal Ig without Blood Contamination

Measurements of IgG and IgA in human rectal secretions are used to evaluate the Abs elicited by HIV vaccines or the bioaccumulation following immunoprophylaxis at the sites of HIV exposure. To improve sampling methods and tolerability of the procedure, we optimized a balloon device (OriCol) for rectal microbiome sampling requiring 10 second inflation and compared this method to a 5 minute collection using sponges. Lubrication of the device did not interfere with IgG, IgA, or hemoglobin ELISA. Lubricated OriCols inflated to 30 cc minimized hemoglobin contamination (<4.68 ng/ml) compared with collections with two sponge types (Weck-Cel: 267.2 ng/ml, p < 0.0001; and Merocel: 59.38 ng/ml, p = 0.003). Median human serum albumin for OriCols was 14.9 μg/ml, whereas Merocels and Weck-Cels were 28.57 μg/ml (p = 0.0005) and 106.2 μg/ml (p = 0.0002), respectively. Consistent with reduced systemic contamination, the median IgG measured in OriCol-collected rectal secretions (986 ng) was lower than secretions from sponges (Weck-Cel: 8588 ng, p < 0.0001; Merocel: 2509 ng, p = 0.0389). The median IgA yield of samples using the OriCol method (75,253 ng) was comparable to that using Merocel (71,672 ng; p = 0.6942) but significantly higher than Weck-Cel sponges (16,173 ng, p = 0.0336). Median recovery volumes for OriCols were 800 μl, whereas Merocels and Weck-Cels were 615 μl (p = 0.0010) and 655 μl (p = 0.0113), respectively. The balloon device was acceptable among 23 participants, as 85.1% experiencing their first collection ranked it as "seven: acceptable - a lot" or "six: acceptable - somewhat" in a seven-point Likert scale. Therefore, lubricated OriCols inflated to 30 cc allowed for a rapid, well-tolerated, blood-free collection of human rectal secretions.

HIV and SIV in Body Fluids: From Breast Milk to the Genitourinary Tract

HIV-1 is present in many secretions including oral, intestinal, genital, and breast milk. However, most people exposed to HIV-1 within these mucosal compartments do not become infected despite often frequent and repetitive exposure over prolonged periods of time. In this review, we discuss what is known about the levels of cell-free HIV RNA, cell-associated HIV DNA and cell-associated HIV RNA in external secretions. Levels of virus are usually lower than contemporaneously obtained blood, increased in settings of inflammation and infection, and decreased in response to antiretroviral therapy. Additionally, each mucosal compartment has unique innate and adaptive immune responses that affect the composition and presence of HIV-1 within each external secretion. We discuss the current state of knowledge about the types and amounts of virus present in the various excretions, touch on innate and adaptive immune responses as they affect viral levels, and highlight important areas for further study.

Sexually transmitted infections and HIV RNA levels in blood and anogenital compartments among Thai men who have sex with men before and after antiretroviral therapy: implication for Treatment as Prevention programme

INTRODUCTION

Sexually transmitted infections (STIs) are common among HIV-positive men who have sex with men (MSM). There have been concerns that undiagnosed and untreated STIs could undermine efforts to use antiretroviral therapy (ART) for prevention due to genital secretion infectiousness. We evaluated the correlation between STIs and HIV RNA in anogenital compartments among HIV-positive MSM before and after ART.

METHODS

MSM participants newly diagnosed with HIV were offered ART regardless of CD4 count during November 2012 to November 2015. Syphilis serology, oropharyngeal swab, rectal swab, urine collection for gonorrhoea and chlamydia nucleic acid amplification testing, and HIV RNA measurement in blood, semen and rectal samples were performed at baseline, 12 and 24 months thereafter.

RESULTS

Of 143 HIV-positive MSM, 16.1% had syphilis, 23.1% had gonorrhoea and 32.8% had chlamydia at baseline. Participants with STIs at baseline had higher median HIV RNA levels in blood plasma (p = 0.053), seminal plasma (p = 0.01) and rectal secretions (p = 0.002) than those without STIs. Multivariate models identified HIV RNA 100,000 to 500,000 (OR 6.74, 95% CI 2.24 to 20.28, p = 0.001) and >500,000 (OR 9.39, 95% CI 1.08 to 81.72, p = 0.04) copies/mL in blood, CD4 count <350 cells/mm3 (OR 4.20, 95% CI 1.05 to 16.70, p = 0.04) and having any STIs (OR 2.62, 95% CI 1.01 to 6.80 p = 0.047) to be associated with detectable (>40 copies/mL) seminal plasma HIV RNA. Having chlamydia at any sites (OR 3.17, 95% CI 1.07 to 9.44, p = 0.04) was associated with detectable rectal HIV RNA. Incidences of syphilis, gonorrhoea and chlamydia were 13.4, 16.4 and 18.1 per 100 person-years respectively. Nine participants had detectable HIV RNA (five in blood, one in semen, two in rectal samples and one in both blood and rectal samples) at 12 and/or 24 months after ART.

CONCLUSIONS

STIs were extremely common among HIV-positive MSM prior to and after ART. ART effectively reduced HIV RNA in all compartments. The correlation between STIs and anogenital HIV RNA, especially prior to ART and likely until complete HIV RNA suppression from ART is achieved, points to the importance of integrating asymptomatic STIs screening into Treatment as Prevention programme for MSM.

High-grade anal intraepithelial neoplasia is associated with HIV-1 RNA rectal shedding in virologically suppressed MSM

OBJECTIVE

The protective effect of ART has not yet been definitively established in MSM. We aimed to characterize the factors associated with persistent HIV-1 RNA rectal shedding.

METHODS

Prospective study including virologically suppressed MSM from an HIV cohort. High-resolution anoscopy (HRA) was performed for screening of anal dysplasia, and rectal sampling for HIV-1 RNA quantification and sexually transmitted infections (STIs) investigation through multiplex PCR. Both generalized linear mixed (GLM) and zero-altered negative binomial (ZANB) models were performed.

RESULTS

One hundred and fifty-five rectal swab samples from 132 virologically suppressed MSM were included. HIV-1 RNA was detectable in 61 (39.3%) samples, with median (IQR) rectal viral load (rVL) of 295.8 (158.8-522) copies/swab. Multivariable GLM showed that the presence of high-grade anal intraepithelial neoplasia (HG-AIN; OR 2.85 [95% CI 1.10-7.38]) and a protease inhibitor-based regimen (OR 2.49 [0.98-6.34]) resulted in increased risk for rectal HIV-1 shedding, whereas higher nadir CD4+/CD8+ T-cell ratio (OR 0.18 [0.04-0.93]) was negatively associated with rectal shedding. ZANB analyses showed that the best predictors of having detectable rVL were lower nadir CD4+/CD8+ T-cell ratio (OR 0.98 [0.96-0.99]) and PI-based regimens (OR 4.85 [1.29-18.24]); the presence of HG-AIN (RR 2.50 [1.41-4.45]), and a higher burden of STIs (RR 1.39 [1.03-1.85]) were predictors of rectal HIV-1 shedding intensity.

CONCLUSION

The prevalence of HIV-1 RNA rectal shedding is high in virologically suppressed MSM. In addition to ART and the immune system integrity, local factors, including the co-existence of HG-AIN and the burden of STIs, may account for the persistence of HIV-1 RNA shedding in rectal mucosa.

High prevalence of HIV, chlamydia and gonorrhoea among men who have sex with men and transgender women attending trusted community centres in Abuja and Lagos, Nigeria

Introduction

Sexually transmitted infection (STI) and HIV prevalence have been reported to be higher amongst men who have sex with men (MSM) in Nigeria than in the general population. The objective of this study was to characterize the prevalence of HIV, chlamydia and gonorrhoea in this population using laboratory-based universal testing.

Methods

TRUST/RV368 represents a cohort of MSM and transgender women (TGW) recruited at trusted community centres in Abuja and Lagos, Nigeria, using respondent-driven sampling (RDS). Participants undergo a structured comprehensive assessment of HIV-related risks and screening for anorectal and urogenital Chlamydia trachomatis and Neisseria gonorrhoeae, and HIV. Crude and RDS-weighted prevalence estimates with 95% confidence intervals (CIs) were calculated. Log-binomial regression was used to explore factors associated with prevalent HIV infection and STIs.

Results

From March 2013 to January 2016, 862 MSM and TGW (316 in Lagos and 546 in Abuja) underwent screening for HIV, chlamydia and gonorrhoea at study enrolment. Participants’ median age was 24 years [interquartile range (IQR) 21–27]. One-third (34.2%) were identified as gay/homosexual and 65.2% as bisexual. The overall prevalence of HIV was 54.9%. After adjusting for the RDS recruitment method, HIV prevalence in Abuja was 43.5% (95% CI 37.3–49.6%) and in Lagos was 65.6% (95% CI 54.7–76.5%). The RDS-weighted prevalence of chlamydia was 17.0% (95% CI 11.8–22.3%) in Abuja and 18.3% (95% CI 11.1–25.4%) in Lagos. Chlamydia infection was detected only at the anorectal site in 70.2% of cases. The RDS-weighted prevalence of gonorrhoea was 19.1% (95% CI 14.6–23.5%) in Abuja and 25.8% (95% CI 17.1–34.6%) in Lagos. Overall, 84.2% of gonorrhoea cases presented with anorectal infection only. Over 95% of STI cases were asymptomatic. In a multivariable model, increased risk for chlamydia/gonorrhoea was associated with younger age, gay/homosexual sexual orientation and higher number of partners for receptive anal sex. HIV infection was associated with older age, female gender identity and number of partners for receptive anal sex.

Conclusions

There is a high burden of infection with HIV and asymptomatic chlamydia and gonorrhoea among MSM and TGW in Nigeria. Most cases would have been missed without anorectal screening. Interventions are needed to target this population for appropriate STI screening and management beginning at a young age.

Shedding of Hepatitis C Virus Into the Rectum of HIV-infected Men Who Have Sex With Men

BACKGROUND

For over a decade we have known of an epidemic of sexually transmitted hepatitis C virus (HCV) infection among human immunodeficiency virus (HIV)-infected men who have sex with men (MSM), but there still remains significant controversy over which bodily fluid(s) are responsible for HCV transmission in these men.

METHODS

We enrolled HIV-infected MSM with recent and chronic HCV infection and quantified HCV from rectal fluid obtained by blind swab. We compared the rectal HCV viral load (VL) with paired blood HCV VL.

RESULTS

We found rectal HCV shedding in 20 (47%) of 43 men, only one (2%) of whom had visible bleeding. Detection of rectal HCV shedding was associated with blood VL > 5 log₁₀ IU/mL (p = .01), and 85% with blood VL > 5 log₁₀ IU/mL had rectal shedding. The HCV VL of the rectal fluid ranged from 2.6 to 5.5 log₁₀ IU/mL. Based on the median rectal fluid VL, the surface of an average human penis would be exposed to at least 2,300 IU of HCV for the duration of anal intercourse.

CONCLUSION

This study provides the first direct evidence to our knowledge that a sufficient quantity of HCV is shed into the rectum in HIV-infected men with HCV infection to directly infect an inserted penis or be passed indirectly through fomite-like transmission to the rectum of sex partner. We must develop an appropriate public health campaign to educate MSM about these routes of HCV infection to reverse the HCV epidemic among HIV-infected MSM.

A Case of Long-Term Seronegative Human Immunodeficiency Virus (HIV) Infection: The Importance of the Humoral Response to HIV

Background. Seronegative human immunodeficiency virus (HIV) infections are exceedingly rare but might inform HIV-host physiology.

Methods. We investigate the cause and consequences of a patient infected with HIV who did not mount a humoral response to HIV for 4 years.

Results. The patient was confirmed HIV-uninfected by nucleic acid testing 4 months before rapidly progressing to acquired immune deficiency syndrome. The patient's humoral deficit was specific to HIV: he mounted robust humoral responses to all challenge vaccines including influenza A(H1N1)pdm09 and all T cell-dependent and -independent serotypes in the 23-valent pneumococcal polysaccharide vaccine. The virus had similar gp120 antigenicity to HIV-positive control serum as NL4-3 and YU2 prototype strains. Two human leukocyte antigen alleles associated with rapid progression were identified (B*08 and B*35), and a cytotoxic T-lymphocyte epitope site variant was noted: E277K. Viral decay (t_1/2 ≈ 39 weeks) suggested that relatively long-lived cells were the source of ongoing viremia. Human immunodeficiency virus viremia was not suppressed until after the patient developed a humoral immune response, despite therapeutic antiretroviral levels. No resistance was detected by virtual phenotyping of virus obtained from serum or from gastrointestinal biopsies despite considerable antiretroviral selection pressure.

Conclusions. Ineffective antibody production may be associated with a subgroup of extremely rapid HIV progressors. Although antiretroviral therapy may be sufficient to slow propagation of infection, it appears to be ineffective for HIV viral clearance in the absence of a humoral response.

Viral Loads Among HIV-Infected Persons Diagnosed With Primary and Secondary Syphilis in 4 US Cities: New York City, Philadelphia, PA, Washington, DC, and Phoenix, AZ

BACKGROUND

Incident syphilis among HIV-infected persons indicates the ongoing behavioral risk for HIV transmission. Detectable viral loads (VLs) among coinfected cases may amplify this risk.

METHODS

Primary and secondary cases reported during 2009-2010 from 4 US sites were crossmatched with local HIV surveillance registries to identify syphilis case-persons infected with HIV before or shortly after the syphilis diagnosis. We examined HIV VL and CD4 results collected within 6 months before or after syphilis diagnosis for the coinfected cases identified. Independent correlates of detectable VLs (≥200 copies/mL) were determined.

RESULTS

We identified 1675 cases of incident primary or secondary syphilis among persons with HIV. Median age was 37 years; 99.5% were men, 41.1% were African American, 24.5% were Hispanics, and 79.9% of the HIV diagnoses were made at least 1 year before syphilis diagnosis. Among those coinfected, there were no VL results reported for 188 (11.2%); of the 1487 (88.8%) with reported VL results, 809 (54.4%) had a detectable VL (median, 25,101 copies/mL; range, 206-3,590,000 copies/mL). Detectable VLs independently correlated with syphilis diagnosed at younger age, at an sexually transmitted disease clinic, and closer in time to HIV diagnosis.

CONCLUSIONS

More than half of syphilis case-persons identified with HIV had a detectable VL collected within 6 months of the syphilis diagnosis. This suggests virologic and active behavioral risk for transmitting HIV.

Anogenital HIV RNA in Thai men who have sex with men in Bangkok during acute HIV infection and after randomization to standard vs. intensified antiretroviral regimens

INTRODUCTION

HIV transmission risk is highest during acute HIV infection (AHI). We evaluated HIV RNA in the anogenital compartment in men who have sex with men (MSM) during AHI and compared time to undetectable HIV RNA after three-drug versus five-drug antiretroviral therapy (ART) to understand risk for onward HIV transmission.

METHODS

MSM with AHI (n=54) had blood, seminal plasma and anal lavage collected for HIV RNA at baseline, days 3 and 7, and weeks 2, 4, 12 and 24. Data were compared between AHI stages: 1 (fourth-generation antigen-antibody combo immunoassay [IA]-, third-generation IA-, n=15), 2 (fourth-generation IA+, third-generation IA-, n=9) and 3 (fourth-generation IA+, third-generation IA+, western blot-/indeterminate, n=30) by randomization to five-drug (tenofovir+emtricitabine+efavirenz+raltegravir+maraviroc, n=18) versus three-drug (tenofovir+emtricitabine+efavirenz, n=18) regimens.

RESULTS

Mean age was 29 years and mean duration since HIV exposure was 15.4 days. Mean baseline HIV RNA was 5.5 in blood, 3.9 in seminal plasma and 2.6 log10 copies/ml in anal lavage (p<0.001). Blood and seminal plasma HIV RNA were higher in AHI Stage 3 compared to Stage 1 (p<0.01). Median time from ART initiation to HIV RNA <50 copies/ml was 60 days in blood, 15 days in seminal plasma and three days in anal lavage. Compared with the three-drug ART, the five-drug ART had a shorter time to HIV RNA <1500 copies/ml in blood (15 vs. 29 days, p=0.005) and <50 copies/ml in seminal plasma (13 vs. 24 days, p=0.048).

CONCLUSIONS

Among MSM with AHI, HIV RNA was highest in blood, followed by seminal plasma and anal lavage. ART rapidly reduced HIV RNA in all compartments, with regimen intensified by raltegravir and maraviroc showing faster HIV RNA reductions in blood and seminal plasma.

The Impact of Implementing a Test, Treat and Retain HIV Prevention Strategy in Atlanta among Black Men Who Have Sex with Men with a History of Incarceration: A Mathematical Model

Background

Annually, 10 million adults transition through prisons or jails in the United States (US) and the prevalence of HIV among entrants is three times higher than that for the country as a whole. We assessed the potential impact of increasing HIV Testing/Treatment/Retention (HIV-TTR) in the community and within the criminal justice system (CJS) facilities, coupled with sexual risk behavior change, focusing on black men-who-have-sex-with-men, 15–54 years, in Atlanta, USA.

Methods

We modeled the effect of a HIV-TTR strategy on the estimated cumulative number of new (acquired) infections and mortality, and on the HIV prevalence at the end of ten years. We additionally assessed the effect of increasing condom use in all settings.

Results

In the Status Quo scenario, at the end of 10 years, the cumulative number of new infections in the community, jail and prison was, respectively, 9246, 77 and 154 cases; HIV prevalence was 10815, 69 and 152 cases, respectively; and the cumulative number of deaths was 2585, 18 and 34 cases, respectively. By increasing HIV-TTR coverage, the cumulative number of new infections could decrease by 15% in the community, 19% in jail, and 8% in prison; HIV prevalence could decrease by 8%, 9% and 7%, respectively; mortality could decrease by 20%, 39% and 18%, respectively. Based on the model results, we have shown that limited use and access to condoms have contributed to the HIV incidence and prevalence in all settings.

Conclusions

Aggressive implementation of a CJS-focused HIV-TTR strategy has the potential to interrupt HIV transmission and reduce mortality, with benefit to the community at large. To maximize the impact of these interventions, retention in treatment, including during the period after jail and prison release, and increased condom use was vital for decreasing the burden of the HIV epidemic in all settings.

Comparison of models for analyzing two-group, cross-sectional data with a Gaussian outcome subject to a detection limit

A potential difficulty in the analysis of biomarker data occurs when data are subject to a detection limit. This detection limit is often defined as the point at which the true values cannot be measured reliably. Multiple, regression-type models designed to analyze such data exist. Studies have compared the bias among such models, but few have compared their statistical power. This simulation study provides a comparison of approaches for analyzing two-group, cross-sectional data with a Gaussian-distributed outcome by exploring statistical power and effect size confidence interval coverage of four models able to be implemented in standard software. We found using a Tobit model fit by maximum likelihood provides the best power and coverage. An example using human immunodeficiency virus type 1 ribonucleic acid data is used to illustrate the inferential differences in these models.

Expansion of HAART coverage is associated with sustained decreases in HIV/AIDS morbidity, mortality and HIV transmission: the "HIV Treatment as Prevention" experience in a Canadian setting

Background

There has been renewed call for the global expansion of highly active antiretroviral therapy (HAART) under the framework of HIV treatment as prevention (TasP). However, population-level sustainability of this strategy has not been characterized.

Methods

We used population-level longitudinal data from province-wide registries including plasma viral load, CD4 count, drug resistance, HAART use, HIV diagnoses, AIDS incidence, and HIV-related mortality. We fitted two Poisson regression models over the study period, to relate estimated HIV incidence and the number of individuals on HAART and the percentage of virologically suppressed individuals.

Results

HAART coverage, median pre-HAART CD4 count, and HAART adherence increased over time and were associated with increasing virological suppression and decreasing drug resistance. AIDS incidence decreased from 6.9 to 1.4 per 100,000 population (80% decrease, p = 0.0330) and HIV-related mortality decreased from 6.5 to 1.3 per 100,000 population (80% decrease, p = 0.0115). New HIV diagnoses declined from 702 to 238 cases (66% decrease; p = 0.0004) with a consequent estimated decline in HIV incident cases from 632 to 368 cases per year (42% decrease; p = 0.0003). Finally, our models suggested that for each increase of 100 individuals on HAART, the estimated HIV incidence decreased 1.2% and for every 1% increase in the number of individuals suppressed on HAART, the estimated HIV incidence also decreased by 1%.

Conclusions

Our results show that HAART expansion between 1996 and 2012 in BC was associated with a sustained and profound population-level decrease in morbidity, mortality and HIV transmission. Our findings support the long-term effectiveness and sustainability of HIV treatment as prevention within an adequately resourced environment with no financial barriers to diagnosis, medical care or antiretroviral drugs. The 2013 Consolidated World Health Organization Antiretroviral Therapy Guidelines offer a unique opportunity to further evaluate TasP in other settings, particularly within generalized epidemics, and resource-limited setting, as advocated by UNAIDS.

The immunological synapse: the gateway to the HIV reservoir

A major challenge in the development of a cure for human immunodeficiency virus (HIV) has been the incomplete understanding of the basic mechanisms underlying HIV persistence during antiretroviral therapy. It is now realized that the establishment of a latently infected reservoir refractory to immune system recognition has thus far hindered eradication efforts. Recent investigation into the innate immune response has shed light on signaling pathways downstream of the immunological synapse critical for T-cell activation and establishment of T-cell memory. This has led to the understanding that the cell-to-cell contacts observed in an immunological synapse that involve the CD4⁺ T cell and antigen-presenting cell or T-cell–T-cell interactions enhance efficient viral spread and facilitate the induction and maintenance of latency in HIV-infected memory T cells. This review focuses on recent work characterizing the immunological synapse and the signaling pathways involved in T-cell activation and gene regulation in the context of HIV persistence.

Dolutegravir pharmacokinetics in the genital tract and colorectum of HIV-negative men after single and multiple dosing

OBJECTIVES

To describe first-dose and steady state pharmacokinetics (PKs) of dolutegravir (DTG) in blood plasma (BP), seminal fluid (SF), colorectal tissue (RT), and rectal mucosal fluid (RF) of healthy HIV-negative men.

DESIGN

A phase 1, open-label, PK study that enrolled 12 healthy men taking 50 mg DTG daily for 8 days.

METHODS

Eleven paired BP samples and 3 SF and RF samples were collected over 24 hours after first (PK1) and multiple (PK2) dosing. RT biopsies were collected at 1 of 6 time points at PK1 and PK2 to generate composite PK profiles. DTG concentrations were analyzed by validated liquid chromatography-tandem mass spectrometry (LC-MS/MS). Noncompartmental PK analysis was conducted with Phoenix WinNonlin v6.3, and Spearman rank correlations were determined using SAS v9.3.

RESULTS

BP area under the concentration-time curves (AUCs) were similar to previous reports, and concentrations at 24 hours (C24 h) were 6- to 34-fold greater than the protein-adjusted concentration required for 90% viral inhibition (PA-IC90) of 64 ng/mL. SF exposures were <7% of BP and below the PA-IC90. RT exposures were 17% of BP and ∼2-fold greater than the PA-IC90. RF AUCs were ∼2%-5% of RT and did not correlate with RT (rho = 0.43, P = 0.17). Accumulation of DTG with multiple dosing was observed in BP, SF, and RT.

CONCLUSIONS

DTG BP PKs were consistent with previously published values. SF concentrations were <7% BP, with SF C24 h below the PA-IC90. However, SF protein binding was not measured. Although the AUC of DTG in RT was <20% BP, RT C24 h remained ∼2-fold higher than the PA-IC90. RF was not a strong surrogate for RT concentrations.

Antiretroviral treatment of HIV-1 prevents transmission of HIV-1: where do we go from here?

Antiretroviral drugs that inhibit viral replication were expected to reduce transmission of HIV by lowering the concentration of HIV in the genital tract. In 11 of 13 observational studies, antiretroviral therapy (ART) provided to an HIV-infected index case led to greatly reduced transmission of HIV to a sexual partner. In the HPTN 052 randomised controlled trial, ART used in combination with condoms and counselling reduced HIV transmission by 96·4%. Evidence is growing that wider, earlier initiation of ART could reduce population-level incidence of HIV. However, the full benefits of this strategy will probably need universal access to very early ART and excellent adherence to treatment. Challenges to this approach are substantial. First, not all HIV-infected individuals can be located, especially people with acute and early infection who are most contagious. Second, the ability of ART to prevent HIV transmission in men who have sex with men (MSM) and people who use intravenous drugs has not been shown. Indeed, the stable or increased incidence of HIV in MSM in some communities where widespread use of ART has been established emphasises the concern that not enough is known about treatment as prevention for this crucial population. Third, although US guidelines call for immediate use of ART, such guidelines have not been embraced worldwide. Some experts do not believe that immediate or early ART is justified by present evidence, or that health-care infrastructure for this approach is sufficient. These concerns are very difficult to resolve. Ongoing community-based prospective trials of early ART are likely to help to establish the population-level benefit of ART, and-if successful-to galvanise treatment as prevention.

Residual immune dysregulation syndrome in treated HIV infection

Antiretroviral therapy has revolutionized the course of HIV infection, improving immune function and decreasing dramatically the mortality and morbidity due to the opportunistic complications of the disease. Nonetheless, even with sustained suppression of HIV replication, many HIV-infected persons experience a syndrome characterized by increased T cell activation and evidence of heightened inflammation and coagulation. This residual immune dysregulation syndrome or RIDS is more common in persons who fail to increase circulating CD4+ T cells to normal levels and in several epidemiologic studies it has been associated with increased morbidity and mortality. These morbid and fatal events are not the typical opportunistic infections and malignancies seen in the early AIDS era but rather comprise a spectrum of cardiovascular events, liver disease, metabolic disorders, kidney disease, bone disease, and a spectrum of malignant complications distinguishable from the opportunistic malignancies that characterized the earlier days of the AIDS epidemic. While immune activation, inflammation, and coagulopathy are characteristic of untreated HIV infection and improve with drug-induced control of HIV replication, the drivers of RIDS in treated HIV infection are incompletely understood. And while inflammation, immune activation, and coagulopathy are more common in treated persons who fail to restore circulating CD4+ T cells, it is not entirely clear how these two phenomena are linked.

Antiretroviral pharmacology in mucosal tissues

Strategies to prevent HIV infection using preexposure prophylaxis are required to curtail the HIV pandemic. The mucosal tissues of the genital and rectal tracts play a critical role in HIV acquisition, but antiretroviral (ARV) disposition and correlates of efficacy within these tissues are not well understood. Preclinical and clinical strategies to describe ARV pharmacokinetic-pharmacodynamic relationships within mucosal tissues are currently being investigated. In this review, we summarize the physicochemical and biologic factors influencing ARV tissue exposure. Furthermore, we discuss the necessary steps to generate relevant pharmacokinetic-pharmacodynamic data and the challenges associated with this process. Finally, we suggest how preclinical and clinical data might be practically translated into optimal preexposure prophylaxis dosing strategies for clinical trials testing using mathematical modeling and simulation.

Human immunodeficiency viruses appear compartmentalized to the female genital tract in cross-sectional analyses but genital lineages do not persist over time

BACKGROUND

Whether unique human immunodeficiency type 1 (HIV) genotypes occur in the genital tract is important for vaccine development and management of drug resistant viruses. Multiple cross-sectional studies suggest HIV is compartmentalized within the female genital tract. We hypothesize that bursts of HIV replication and/or proliferation of infected cells captured in cross-sectional analyses drive compartmentalization but over time genital-specific viral lineages do not form; rather viruses mix between genital tract and blood.

METHODS

Eight women with ongoing HIV replication were studied during a period of 1.5 to 4.5 years. Multiple viral sequences were derived by single-genome amplification of the HIV C2-V5 region of env from genital secretions and blood plasma. Maximum likelihood phylogenies were evaluated for compartmentalization using 4 statistical tests.

RESULTS

In cross-sectional analyses compartmentalization of genital from blood viruses was detected in three of eight women by all tests; this was associated with tissue specific clades containing multiple monotypic sequences. In longitudinal analysis, the tissues-specific clades did not persist to form viral lineages. Rather, across women, HIV lineages were comprised of both genital tract and blood sequences.

CONCLUSIONS

The observation of genital-specific HIV clades only in cross-sectional analysis and an absence of genital-specific lineages in longitudinal analyses suggest a dynamic interchange of HIV variants between the female genital tract and blood.

HIV-1 pathogenesis: the virus

Transmission of HIV-1 results in the establishment of a new infection, typically starting from a single virus particle. That virion replicates to generate viremia and persistent infection in all of the lymphoid tissue in the body. HIV-1 preferentially infects T cells with high levels of CD4 and those subsets of T cells that express CCR5, particularly memory T cells. Most of the replicating virus is in the lymphoid tissue, yet most of samples studied are from blood. For the most part the tissue and blood viruses represent a well-mixed population. With the onset of immunodeficiency, the virus evolves to infect new cell types. The tropism switch involves switching from using CCR5 to CXCR4 and corresponds to an expansion of infected cells to include naïve CD4(+) T cells. Similarly, the virus evolves the ability to enter cells with low levels of CD4 on the surface and this potentiates the ability to infect macrophages, although the scope of sites where infection of macrophages occurs and the link to pathogenesis is only partly known and is clear only for infection of the central nervous system. A model linking viral evolution to these two pathways has been proposed. Finally, other disease states related to immunodeficiency may be the result of viral infection of additional tissues, although the evidence for a direct role for the virus is less strong. Advancing immunodeficiency creates an environment in which viral evolution results in viral variants that can target new cell types to generate yet another class of opportunistic infections (i.e., HIV-1 with altered tropism).

Does ART prevent HIV transmission among MSM?

OBJECTIVE

To review the evidence for antiretroviral 'treatment as prevention' for HIV transmission among MSM.

METHODS

We reviewed studies that assess the biological plausibility that virally suppressive antiretroviral therapy (ART) reduces HIV infectiousness via anal intercourse and the epidemiologic evidence of whether ART has played a role in attenuating HIV incidence among MSM.

RESULTS

Although ART treatment among MSM is likely to provide some preventive benefit, it is unknown whether it will reduce HIV infectiousness via anal intercourse to the same extent as via penile-vaginal intercourse. Additional research is needed on the pharmacokinetic properties of specific antiretroviral agents in the gastrointestinal tract. Estimates of risk behaviors and the incidence of HIV among MSM before and after the introduction and expansion of ART suggest that the population-level protective benefits of ART may be attenuated by a number of factors, most notably, continuing or increasing frequency of condomless anal intercourse and incidence of other sexually transmitted infections (STIs). Additional studies are needed on the impact of ART on HIV sexual risk behaviors and transmission among MSM outside of developed countries in North America, western Europe, and Australia.

CONCLUSION

The benefits of treatment as prevention for MSM are highly plausible, but not certain. In the face of these unknowns, treatment guidelines for earlier ART initiation should be considered within a combination prevention strategy that includes earlier diagnosis, expanded STI treatment, and structural and behavioral interventions.

Condom Use, Disclosure, and Risk for Unprotected Sex in HIV-Negative Midlife and Older Men Who Have Sex With Men

Sexual risk behaviors account for most HIV infections in men who have sex with men (MSM), and the risk of exposure from each sexual encounter increases with age. The focus of this study was to investigate which behaviors in midlife and older MSM influence their sexual risk/protection. Cross-sectional data were collected from a community-based sample of 802 MSM aged 40 years and older from community venues (e.g., bars) who completed an anonymous questionnaire. Data from a subset of 420 MSM who were HIV-negative (aged 40-81 years) were used to investigate which behaviors were associated with greater risk for unprotected anal sex. Regression analyses indicated that erection difficulties (odds ratio [OR] = 4.7; 95% confidence interval [CI] = 1.8-12.2), practicing safe sex with outside partners but not with one’s primary partner (OR = 0.54; 95% CI = 0.3-0.94), and recreational drug use (OR = 2.6; 95% CI = 1.3-5.1) were associated with higher risk for unprotected receptive anal intercourse. Younger age (OR = 0.96; 95% CI = 0.9- 0.9), not telling partners about HIV status (OR = 3.2; 95% CI = 1.5-6.5), finding partners in backrooms/sex clubs (OR = 2.8; 95% CI = 1.1- 6.8), and erection difficulties (OR = 10.3; 95% CI = 2.8-37.8) were associated with higher risk for unprotected insertive anal intercourse. These data indicate there may be certain factors specific to older MSM that influence their sexual risk taking behaviors. Programs may be more effective if they are tailored for older cohorts of MSM and address interpersonal communication, erection problems, and substance use to reduce health risks and promote healthier lifestyles.

Highly active antiretroviral therapy does not completely suppress HIV in semen of sexually active HIV-infected men who have sex with men

OBJECTIVE

Although HAART can suppress genital shedding and sexual transmission of HIV, men who have sex with men (MSM) have experienced a resurgent HIV epidemic in the HAART era. Many HIV-infected MSM continue to engage in unsafe sex, and sexually transmitted infections (STIs) or other factors may promote genital HIV shedding and transmission in this population despite HAART. In this study, we determined the prevalence of seminal HIV shedding in HIV-infected MSM on stable HAART, and its relationship with a number of clinical, behavioral and biological variables.

DESIGN

Sexually active HIV-infected men using HAART were recruited from an MSM health clinic to provide semen and blood samples.

METHODS

HIV levels were assessed in paired semen and blood samples by PCR. Clinical and behavioral data were obtained from medical records and questionnaires. Herpes simplex virus 2 (HSV-2) serostatus, seminal HSV-2 DNA, and markers of genital inflammation were measured using standard laboratory methods.

RESULTS

Overall, HIV-1 was detected in 18 of 101 (18%) blood and 30 of 101 (30%) semen samples. Of 83 men with undetectable HIV in blood plasma, 25% had HIV in semen with copy numbers ranging from 80 to 2560. Multivariate analysis identified STI/urethritis (P = 0.003), tumor necrosis factor α (P = 0.0003), and unprotected insertive anal sex with an HIV-infected partner (P = 0.007) as independent predictors of seminal HIV detection.

CONCLUSION

STIs and genital inflammation can partially override the suppressive effect of HAART on seminal HIV shedding in sexually active HIV-infected MSM. Low seminal HIV titers could potentially pose a transmission risk in MSM, who are highly susceptible to HIV infection.

HIV-1 RNA rectal shedding is reduced in men with low plasma HIV-1 RNA viral loads and is not enhanced by sexually transmitted bacterial infections of the rectum

BACKGROUND

Among human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) taking combination antiretroviral therapy (cART), the impact of rectal sexually transmitted infections (STIs) on rectal HIV-1 shedding is unknown.

METHODS

Human immunodeficiency virus type 1 (HIV-1) RNA was quantified from rectal swabs collected for Neisseria gonorrhoeae (GC) and Chlamydia trachomatis (CT) screening of HIV-1-infected MSM. Correlations of STIs with rectal viral load were explored using multinomial regression modeling. HIV-1 coreceptor tropism was predicted from sequencing in a subset of men.

RESULTS

Thirty-one (39%) of 80 men (59 prescribed combination antiretroviral therapy [cART]) had HIV detected in 38 (42%) of 91 rectal swabs. Rectal HIV detection was associated with plasma virus loads above 3.15 log₁₀ copies/mL (95% confidence limit [CL] 2.73, 3.55) and paired rectal viral loads and plasma viral loads were correlated (Kendall's tau [τ] 0.68, Spearman rho [P] = .77). Rectal STIs and abnormal anal cytology were not associated with rectal viral load. HIV coreceptor distribution was very similar between the plasma and rectum in 3 of 4 men.

CONCLUSIONS

Plasma and rectal viral load were correlated, and rectal STIs did not increase the likelihood of detecting HIV in the rectal secretions in MSM, including those with low or undetectable plasma viral load. Suppressing plasma viral load is likely to reduce risk of HIV transmission to insertive partners.

HIV transmission: time for translational studies to bridge the gap

More than 7000 new HIV infections are documented each day worldwide. In this Perspective, we dissect new results from a large clinical trial showing that genital and plasma HIV-1 RNA loads predict the risk of heterosexual transmission and that genital tract viral RNA load does so independently of plasma viral load. Furthermore, beyond its defined study end points, this well-conducted trial identified new research directions that should be pursued in smaller intensive basic and translational studies.

Rapid dissemination of SIV follows multisite entry after rectal inoculation

Receptive ano-rectal intercourse is a major cause of HIV infection in men having sex with men and in heterosexuals. Current knowledge of the mechanisms of entry and dissemination during HIV rectal transmission is scarce and does not allow the development of preventive strategies. We investigated the early steps of rectal infection in rhesus macaques inoculated with the pathogenic isolate SIVmac251 and necropsied four hours to nine days later. All macaques were positive for SIV. Control macaques inoculated with heat-inactivated virus were consistently negative for SIV. SIV DNA was detected in the rectum as early as four hours post infection by nested PCR for gag in many laser-microdissected samples of lymphoid aggregates and lamina propria but never in follicle-associated epithelium. Scarce SIV antigen positive cells were observed by immunohistofluorescence in the rectum, among intraepithelial and lamina propria cells as well as in clusters in lymphoid aggregates, four hours post infection and onwards. These cells were T cells and non-T cells that were not epithelial cells, CD68⁺ macrophages, DC-SIGN⁺ cells or fascin⁺ dendritic cells. DC-SIGN⁺ cells carried infectious virus. Detection of Env singly spliced mRNA in the mucosa by nested RT-PCR indicated ongoing viral replication. Strikingly, four hours post infection colic lymph nodes were also infected in all macaques as either SIV DNA or infectious virus was recovered. Rapid SIV entry and dissemination is consistent with trans-epithelial transport. Virions appear to cross the follicle-associated epithelium, and also the digestive epithelium. Viral replication could however be more efficient in lymphoid aggregates. The initial sequence of events differs from both vaginal and oral infections, which implies that prevention strategies for rectal transmission will have to be specific. Microbicides will need to protect both digestive and follicle-associated epithelia. Vaccines will need to induce immunity in lymph nodes as well as in the rectum.

Impact of a functional KIR2DS4 allele on heterosexual HIV-1 transmission among discordant Zambian couples

Killer cell immunoglobulin-like receptors (KIRs) and their HLA ligands interact to regulate natural killer (NK) cell function. KIR gene content and allelic variations are reported to influence human immunodeficiency virus (HIV)-1 infection and pathogenesis. We investigated the impact of KIR genes on heterosexual HIV-1 transmission among 566 discordant couples from Lusaka, Zambia. KIR2DS4*001, the only allele of KIR2DS4 known to encode a functional activating receptor, was associated with relatively high viral load for HIV-1 in index (HIV-1 seroprevalent) partners (β [standard error (SE)], .17 [.8] log₁₀; P = .04) and with accelerated transmission of HIV-1 to cohabiting seronegative partners (relative hazard [RH], 2.00; P = .004). The latter association was independent of the direction of transmission (male-to-female or female-to-male), genital ulcers, and carriage of the putative ligand (HLA-Cw*04). No KIR-gene variant in the initially seronegative partners was associated with HIV-1 acquisition or early viral load following seroconversion. Further analysis of NK cell function should clarify the role of KIR2DS4*001 in HIV-1 transmission.

Higher levels of Zidovudine resistant HIV in the colon compared to blood and other gastrointestinal compartments in HIV infection

Background

The gut-associated lymphoid tissue (GALT) is the largest lymphoid organ infected by human immunodeficiency virus type 1 (HIV-1). It serves as a viral reservoir and host-pathogen interface in infection. This study examined whether different parts of the gut and peripheral blood lymphocytes (PBL) contain different drug-resistant HIV-1 variants.

Methods

Gut biopsies (esophagus, stomach, duodenum and colon) and PBL were obtained from 8 HIV-1 infected preHAART (highly active antiretroviral therapy) patients at three visits over 18 months. Patients received AZT, ddI or combinations of AZT/ddI. HIV-1 Reverse transcriptase (RT)-coding sequences were amplified from viral DNA obtained from gut tissues and PBL, using nested PCR. The PCR fragments were cloned and sequenced. The resulting sequences were subjected to phylogenetic analyses, and antiretroviral drug mutations were identified.

Results

Phylogenetic and drug mutation analyses revealed differential distribution of drug resistant mutations in the gut within patients. The level of drug-resistance conferred by the RT sequences was significantly different between different gut tissues and PBL, and varied with antiretroviral therapy. The sequences conferring the highest level of drug-resistance to AZT were found in the colon.

Conclusion

This study confirms that different drug-resistant HIV-1 variants are present in different gut tissues, and it is the first report to document that particular gut tissues may select for drug resistant HIV-1 variants.

Discordance in HIV-1 viral loads and antiretroviral drug concentrations comparing semen and blood plasma

OBJECTIVES

For individuals not on antiretroviral therapy, the risk of heterosexual transmission of HIV appears negligible when blood plasma (BP) viral loads are <1500 HIV-1 RNA copies/mL. It is not clear whether this observation can be extrapolated to individuals on highly active antiretroviral therapy (HAART). Because of differential tissue penetration, antiretroviral drug concentrations may be sufficient to maintain an undetectable viral load in the BP yet not achieve adequate levels to suppress HIV in the genital tract. Therefore, we wanted to correlate HIV viral loads and drug concentrations in semen plasma (SP) and BP.

METHODS

Thirty-three men were included. All were on combination antiretroviral therapy with an undetectable BP viral load for at least 1 year. Blood and semen samples were collected within 2 h of each other and tested for HIV RNA by the NucliSens QT (bioMerieux, St Laurent, QC, Canada) method; drug concentrations were determined by liquid chromatography tandem mass spectrometry.

RESULTS

Two of the 33 patients (6.1%) with BP viral loads below detection had time-matched HIV viral loads in SP > or =700 copies/mL. Both patients were on efavirenz, the SP concentrations of which were < or =10% of the levels in BP and well below the minimal therapeutic drug monitoring target concentration required to suppress HIV.

CONCLUSIONS

Because, at least in part, of poor drug penetration into the genital tract, an undetectable HIV viral load in the BP does not guarantee an undetectable viral load in semen. In view of this, caution should be taken in concluding that patients on HAART with suppressed viraemia are sexually non-infectious.

Male circumcision and HIV status among Latino immigrant MSM in New York City

This study investigated protective effects of circumcision in a sample of immigrant Latino men who have sex with men (MSM). A survey in Portuguese, Spanish, or English was administered with computer-assisted self-interview technology with audio enhancement (A-CASI) to 482 MSM from Brazil (n=146), Colombia (n=169), and the Dominican Republic (n=167), living in the New York metropolitan area. Logistic regression revealed that after controlling for age, income, education, having had syphilis, having done sex work, and preferring the receptive role in anal intercourse, uncircumcised men were almost twice as likely to be HIV-positive as circumcised men. Follow-up analyses revealed, however, that the protective effects occurred only among the group of Colombian men.

Determinants and policy implications of male circumcision in the United States

OBJECTIVE

We sought to determine whether lack of state Medicaid coverage for infant male circumcision correlates with lower circumcision rates.

METHODS

We used data from the Nationwide Inpatient Sample on 417 282 male newborns to calculate hospital-level circumcision rates. We used weighted multiple regression to correlate hospital circumcision rates with hospital-level predictors and state Medicaid coverage of circumcision.

RESULTS

The mean neonatal male circumcision rate was 55.9%. When we controlled for other factors, hospitals in states in which Medicaid covers routine male circumcision had circumcision rates that were 24 percentage points higher than did hospitals in states without such coverage (P<.001). Hospitals serving greater proportions of Hispanic patients had lower circumcision rates; this was not true of hospitals serving more African Americans. Medicaid coverage had a smaller effect on circumcision rates when a hospital had a greater percentage of Hispanic births.

CONCLUSIONS

Lack of Medicaid coverage for neonatal male circumcision correlated with lower rates of circumcision. Because uncircumcised males face greater risk of HIV and other sexually transmitted infections, lack of Medicaid coverage for circumcision may translate into future health disparities for children born to poor families covered by Medicaid.

Human leukocyte antigen class I genotypes in relation to heterosexual HIV type 1 transmission within discordant couples

Differences in immune control of HIV-1 infection are often attributable to the highly variable HLA class I molecules that present viral epitopes to CTL. In our immunogenetic analyses of 429 HIV-1 discordant Zambian couples (infected index partners paired with cohabiting seronegative partners), several HLA class I variants in index partners were associated with contrasting rates and incidence of HIV-1 transmission within a 12-year study period. In particular, A*3601 on the A*36-Cw*04-B*53 haplotype was the most unfavorable marker of HIV-1 transmission by index partners, while Cw*1801 (primarily on the A*30-Cw*18-B*57 haplotype) was the most favorable, irrespective of the direction of transmission (male to female or female to male) and other commonly recognized cofactors of infection, including age and GUI. The same HLA markers were further associated with contrasting viral load levels in index partners, but they had no clear impact on HIV-1 acquisition by the seronegative partners. Thus, HLA class I gene products not only mediate HIV-1 pathogenesis and evolution but also influence heterosexual HIV-1 transmission.

HIV dynamics in seminal plasma during primary HIV infection

HIV dynamics in seminal plasma during primary HIV infection was evaluated through an observational study of individuals with primary HIV infection at the University of Washington Primary Infection Clinic. Seminal plasma HIV RNA was quantified using a real-time reverse transcription PCR assay. Blood plasma RNA was quantified by bDNA or PCR-based assays. Longitudinal analyses of HIV RNA levels over time used random effects regression analysis. From 1993 to 2005, 110 men collected 327 semen specimens. Initial blood and seminal plasma RNA levels in untreated men were only moderately correlated (Spearman r = 0.38, p = 0.0002). Estimated peak and set point levels were lower in semen than blood by 0.8 (p = 0.001) and 0.7 (p < 0.001) log(10) copies/ml, respectively. RNA decay rates were similar in the two compartments (p = 0.4). For 2 months after infection, mean HIV RNA levels in seminal plasma remained above a threshold level (3.8 log(10) copies/ml) that has been associated with recovery of infectious virus in vitro. HIV-positive men are likely to be most infectious in the first months following HIV acquisition. However, the modest relationship between HIV RNA levels in blood and seminal plasma suggests that the relative risk of HIV transmission during primary infection may vary from current estimates that are solely based on blood levels. Incorporating seminal plasma HIV levels into future mathematical models may increase the accuracy of these models.

Compartmentalization of the gut viral reservoir in HIV-1 infected patients

BACKGROUND

Recently there has been an increasing interest and appreciation for the gut as both a viral reservoir as well as an important host-pathogen interface in human immunodefiency virus type 1 (HIV-1) infection. The gut associated lymphoid tissue (GALT) is the largest lymphoid organ infected by HIV-1. In this study we examined if different HIV-1 quasispecies are found in different parts of the gut of HIV-1 infected individuals.

RESULTS

Gut biopsies (esophagus, stomach, duodenum and colorectum) were obtained from eight HIV-1 infected preHAART (highly active antiretroviral therapy) patients. HIV-1 Nef and Reverse transcriptase (RT) encoding sequences were obtained through nested PCR amplification from DNA isolated from the gut biopsy tissues. The PCR fragments were cloned and sequenced. The resulting sequences were subjected to various phylogenetic analyses. Expression of the nef gene and viral RNA in the different gut tissues was determined using real-time RT-PCR. Phylogenetic analysis of the Nef protein-encoding region revealed compartmentalization of viral replication in the gut within patients. Viral diversity in both the Nef and RT encoding region varied in different parts of the gut. Moreover, increased nef gene expression (p < 0.05) and higher levels of viral genome were observed in the colorectum (p < 0.05). These differences could reflect an adaptation of HIV-1 to the various tissues.

CONCLUSION

Our results indicated that different HIV-1 quasispecies populate different parts of the gut, and that viral replication in the gut is compartmentalized. These observations underscore the importance of the gut as a host-pathogen interface in HIV-1 infection.

Herpes simplex virus (HSV) suppression with valacyclovir reduces rectal and blood plasma HIV-1 levels in HIV-1/HSV-2-seropositive men: a randomized, double-blind, placebo-controlled crossover trial

BACKGROUND

Herpes simplex virus type 2 (HSV-2) infection is common among human immunodeficiency virus (HIV)-infected persons, and HSV reactivation increases plasma and genital HIV-1 levels. We studied HIV-1 levels during HSV suppression in coinfected persons in a placebo-controlled crossover trial.

METHODS

Twenty antiretroviral therapy (ART)-naive HIV-1/HSV-2-seropositive men who have sex with men in Lima, Peru, with CD4 cell counts >200 cells/ microL were randomized to receive either valacyclovir at 500 mg twice daily or placebo for 8 weeks, after which they underwent a 2-week washout period and then received the alternative regimen for 8 weeks. Specimens included daily anogenital swabs (for HSV DNA polymerase chain reaction [PCR]), thrice weekly rectal mucosal secretions (for HIV-1 RNA and HSV DNA PCR) obtained by anoscopy, and weekly plasma (for HIV-1 RNA PCR). Outcomes were rectal and plasma HIV-1 RNA levels by treatment arm.

RESULTS

HIV-1 was detected in 73% of 844 rectal and 99% of 288 plasma specimens. HSV was detected in 29% and 4% of mucocutaneous specimens obtained during placebo and valacyclovir administration, respectively (P<.001). Valacyclovir resulted in a 0.16 (95% confidence interval [CI], 0.07-0.25; P=.0008; 33% decrease) log(10) copies/mL lower mean within-subject rectal HIV-1 level and a 0.33 (95% CI, 0.23-0.42; P<.0001; 53% decrease) log(10) copies/mL lower plasma HIV-1 level, compared with values for placebo.

CONCLUSIONS

Valacyclovir significantly reduces rectal and plasma HIV-1 levels in HIV-1/HSV-2-coinfected men. HSV suppression may provide clinical benefits to persons not receiving highly active ART as well as public health benefits.

Male circumcision for prevention of HIV transmission: what the new data mean for HIV prevention in the United States

Recent clinical trials in Africa found that male circumcision reduces the risk of acquiring HIV from heterosexual sex--what are the implications of these studies for the United States?

[Prevention strategies to control the HIV epidemic. Successes, problems, and perspectives]

After the recognition of AIDS as a new disease entity and isolation of HIV as the causative agent in the early 1980s, a controversial debate about adequate measures to reduce the spread of HIV developed. In all developed countries a strategy based on education about modes of HIV transmission, condom promotion and harm reduction approaches to intravenous drug use finally succeeded and became instrumental for the relative containment of HIV within most at risk populations. However, in most developing countries as well as in the countries of Eastern Europe, the success of HIV pre vention remained limited for various reasons. In addition, for several years now, in the western developed countries sexual risk behaviour, newly diagnosed HIV infections, and the incidence of various other sexually transmitted infections seem to re-increase, especially among men who have sex with men (MSM). These increases coincide with a dramatic improvement of therapeutic options for the treatment of HIV infection. The relationship between improvement of therapy and changes in sexual risk behaviour has to be further defined. It is hypothesized that HIV serosorting as a predominant risk management strategy among MSM results in an accumulation of health risks in the HIV-positive MSM population. In addition to and beyond established condom promotion, additional biomedical approaches to reduce transmissibility and susceptibility for HIV will be necessary to regain control of the spread of HIV in highly sexually active populations.

Communication of HIV viral load to guide sexual risk decisions with serodiscordant partners among San Francisco men who have sex with men

The objective of this study was to estimate frequency and correlates of discussing HIV viral load (VL) with serodiscordant sex partners to guide decisions about sexual activities among men who have sex with men (MSM). We conducted a cross-sectional survey of 573 San Francisco MSM. Among 507 who knew their HIV status, 397 (78%) were familiar with the term 'viral load', and half (n=199) had a serodiscordant partner in the prior year. These 199 respondents (n=130 [65%] HIV-positive; n=69 [35%] HIV-negative) were the focus of this analysis. A majority (n=111, 56%) discussed VL in the prior year with serodiscordant partners specifically to guide decisions about sexual risk behaviour. Discussion was more common among HIV-positive than HIV-negative participants (adjusted odds ratio [AOR], 3.5; 95% confidence interval [CI], 1.6-7.6), and African Americans compared to whites (AOR, 3.7; 95% CI, 1.5-9.5). HIV-negative men who discussed VL were more concerned about becoming infected, but also more willing to engage in risky behaviour with a partner whose VL is undetectable, than men not discussing VL. Some HIV-negative men may be discussing VL to engage in higher risk behaviour upon learning of an HIV-positive partner's undetectable VL. Interventions targeting MSM should explain that while risk of transmission is likely reduced with a low blood plasma VL, it is not necessarily eliminated.

Unsafe sexual behavior and correlates of risk in a probability sample of men who have sex with men in the era of highly active antiretroviral therapy

OBJECTIVE

To assess the levels and correlates of potential exposure to and transmission of HIV in a contemporary, community-based probability sample of men who have sex with men (MSM).

METHODS

In 2003, 311 sexually active MSM participated in a random-digit dial telephone survey in Seattle neighborhoods with a high prevalence of MSM. The primary outcomes were potential exposure to and transmission of HIV, defined as unprotected anal intercourse with a man of opposite or unknown HIV status in the preceding 12 months.

RESULTS

Fourteen percent of respondents reported being HIV-positive, 77% reported being HIV-negative, and 8% had not been tested. Of 241 HIV-negative MSM, 25 (10%; 95% confidence interval [CI], 7-15%) were potentially exposed to HIV; among 45 HIV-positive MSM, 14 (31%; 95% CI, 20-46%) were potential HIV-transmitters. Among HIV-negative men, the strongest bivariate correlates of potential exposure to HIV were recent bacterial sexually transmitted disease (odds ratio [OR], 5.8), number of recent male sexual partners (OR, 1.01 per partner), recent sex at a bathhouse (OR, 9.1), and recent use of sildenafil (OR, 4.4), amyl nitrite (OR, 6.2), and methamphetamine (OR, 8.0). Among HIV-infected men, the strongest correlates of potential HIV transmission were recent use of amyl nitrite (OR, 3.1), number of recent male sex partners (OR, 1.07 per partner), and having a male spouse or domestic partner (OR, 0.3).

CONCLUSIONS

Most MSM knew their HIV status and adopted safer sexual behaviors to reduce their risk of HIV acquisition or transmission. However, 10% of HIV-negative MSM and 31% of HIV-positive MSM recently engaged in behaviors that placed them at high risk for acquiring or transmitting HIV.

Differential mucosal susceptibility in HIV-1 transmission and infection

HIV infection occurs primarily through mucosal surfaces, indicating that protection at mucosal sites may be crucial in prevention and treatment. The host innate and adaptive immune elements provide a level of protection, which differs between mucosal compartments, and appears to be most successful in the oral environment, where transmission is rare. In addition to the distinct oral mucosal architecture and cellular constituents, oral fluids, unlike other mucosal secretions, are rarely a vehicle for HIV infection. Multiple soluble factors may contribute to this antiviral activity, including neutralizing antibodies, secretory leukocyte protease inhibitor (SLPI), antiviral peptides such as defensins and cystatins, glycoproteins including thrombospondin and lactoferrin, and complement components. Understanding the antiviral activities of these and other potential resistance factors is becoming increasingly important in attempts to design treatments in the era of HAART resistance. In this regard, the mechanism of anti-HIV action of SLPI has recently been further elucidated by the discovery of its binding protein/receptor, which plays a key role in the infection of macrophages and may consequently be a novel therapeutic target. Continued elucidation of the unique features of mucosal HIV immunology is essential for understanding HIV pathogenesis and for developing effective vaccines and therapeutics.

Binding and transfer of human immunodeficiency virus by DC-SIGN+ cells in human rectal mucosa

The role of DC-SIGN on human rectal mucosal dendritic cells is unknown. Using highly purified human rectal mucosal DC-SIGN+ cells and an ultrasensitive real-time reverse transcription-PCR assay to quantify virus binding, we found that HLA-DR+/DC-SIGN+ cells can bind and transfer more virus than the HLA-DR+/DC-SIGN- cells. Greater than 90% of the virus bound to total mucosal mononuclear cells (MMCs) was accounted for by the DC-SIGN+ cells, which comprise only 1 to 5% of total MMCs. Significantly, anti-DC-SIGN antibodies blocked 90% of the virus binding when more-physiologic amounts of virus inoculum were used. DC-SIGN expression in the rectal mucosa was significantly correlated with the interleukin-10 (IL-10)/IL-12 ratio (r = 0.58, P < 0.002; n = 26) among human immunodeficiency virus (HIV)-positive patients. Ex vivo and in vitro data implicate the role of IL-10 in upregulating DC-SIGN expression and downregulating expression of the costimulatory molecules CD80/CD86. Dendritic cells derived from monocytes (MDDCs) in the presence of IL-10 render the MDDCs less responsive to maturation stimuli, such as lipopolysaccharide and tumor necrosis factor alpha, and migration to the CCR7 ligand macrophage inflammatory protein 3beta. Thus, an increased IL-10 environment could render DC-SIGN(+) cells less immunostimulatory and migratory, thereby dampening an effective immune response. DC-SIGN and the IL-10/IL-12 axis may play significant roles in the mucosal transmission and pathogenesis of HIV type 1.

Transmission of HIV-1 during primary infection: relationship to sexual risk and sexually transmitted infections

OBJECTIVE

To study primary HIV-1 infections (PHI) using molecular and epidemiological approaches in order to assess correlates of transmission in this population.

METHODS

Individuals with PHI were recruited prospectively from a discrete cohort of 1235 individuals under follow-up in a well-defined geographical area between 1999 and 2003. PHI was diagnosed by one of the following: negative HIV antibody test within 18 months, evolving antibody response, or application of the serological testing algorithm for recent HIV seroconversion. The pol gene was sequenced to identify genotypic resistance and facilitate molecular epidemiological analysis. Clinical data were collected and linked in an irretrievable fashion when informed consent was obtained.

RESULTS

A total of 103 individuals with PHI diagnosed between 1999 and 2003 were included in the study; 99 (96%) were male and 90 (91%) were men who have sex with men. Viruses from 35 out of 103 (34%) appeared within 15 phylogenetically related clusters. Significant associations with clustering were: young age, high CD4 cell count, number of sexual contacts, and unprotected anal intercourse (UAI) in the 3 months before diagnosis (P < 0.05 for all). High rates of acute sexually transmitted infections (STI) were observed in both groups with a trend towards higher rates in those individuals with viruses within a cluster (42.9 versus 27.9%; P = 0.13).

CONCLUSION

High rates of partner change, UAI and STI are factors that facilitate onward transmission during PHI. More active identification of individuals during PHI, the management of STI and highly active antiretroviral therapy may all be useful methods to break transmission networks.