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Background: Oral pre-exposure prophylaxis (PrEP) using co-formulated emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) is a potent HIV prevention method for men and women, with its efficacy highly dependent on adherence. A pivotal HIV efficacy study combined with a directly observed pharmacological study defined the thresholds for HIV protection in men who have sex with men (MSM), which are the keys to PrEP promotion and development of new PrEP agents. For African women at risk for HIV and belonging to a priority group considered due to disproportionately high incident HIV infections, the variable adherence in PrEP clinical trials and the limited pharmacologic data have resulted in a lack of clarity about the PrEP adherence required for HIV protection. We propose a study to quantify the adherence-concentration-efficacy thresholds of TDF/FTC PrEP among African cisgender women to inform decisions about optimal PrEP dosing and adherence for HIV protection., Methods: We randomized 45 low-risk HIV-uninfected African women, aged 18-30 years old, to directly observe the TDF/FTC PrEP of two, four, or seven doses per week for 8 weeks. A complementary age-matched pregnant women cohort at high risk of HIV, who will receive seven doses per week, was recruited ( N  = 15) with the primary aim of establishing benchmark concentrations in dried blood spots and peripheral blood mononuclear cells. Plasma, whole blood (WB), urine, hair, vaginal fluid, and vaginal tissue (non-pregnant women only) were archived for future testing. Drug concentrations were measured using methods validated for each biological matrix. Pharmacokinetic models were fitted to drug concentrations to quantify concentration-adherence thresholds. To define the drug concentrations associated with HIV protection, we applied the newly defined thresholds from the primary pharmacologic trial to the subset of women randomized to TDF/FTC or TDF in the Partners PrEP Study with the drug concentration assessed in plasma and WB samples. Multiple imputation was used to construct a data set with drug concentrations at each visit when an HIV test was performed for the entire cohort, replicating the work for MSM., Discussion: The proposed study generated the first African women-specific TDF-PrEP adherence-concentration-efficacy thresholds essential for guiding the accurate interpretation of TDF/FTC PrEP programs and clinical trials of novel HIV prevention products using TDF/FTC as an active control., Clinical Trial Registration: ClinicalTrials.gov, identifier (NCT05057858)., Competing Interests: KM received an investigator sponsored research grant from Gilead Sciences Inc., which was awarded to the University of Washington. DVG has received consulting fees from Gilead and grants or contracts unrelated to this work from the NIH paid to institution. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declared that they were an editorial board member of Frontiers at the time of submission. This had no impact on the peer review process and the final decision., (© 2024 Wu, Saina, Brown, Chege, Donnell, Glidden, Ngure, Mugo, Akelo, Schaafsma, Anderson and Mugwanya.)

Background: We examined the epidemiology and transmission potential of HIV population viral load (VL) in 12 sub-Saharan African countries., Methods: We analyzed data from Population-based HIV Impact Assessments (PHIAs), large national household-based surveys conducted between 2015 and 2019 in Cameroon, Cote d'Ivoire, Eswatini, Kenya, Lesotho, Malawi, Namibia, Rwanda, Tanzania, Uganda, Zambia, and Zimbabwe. Blood-based biomarkers included HIV serology, recency of HIV infection, and VL. We estimated the number of people living with HIV (PLHIV) with suppressed viral load (<1,000 HIV-1 RNA copies/mL) and with unsuppressed viral load (viremic), the prevalence of unsuppressed HIV (population viremia), sex-specific HIV transmission ratios (number female incident HIV-1 infections/number unsuppressed male PLHIV per 100 persons-years [PY] and vice versa) and examined correlations between a variety of VL metrics and incident HIV. Country sample sizes ranged from 10,016 (Eswatini) to 30,637 (Rwanda); estimates were weighted and restricted to participants 15 years and older., Results: The proportion of female PLHIV with viral suppression was higher than that among males in all countries, however, the number of unsuppressed females outnumbered that of unsuppressed males in all countries due to higher overall female HIV prevalence, with ratios ranging from 1.08 to 2.10 (median: 1.43). The spatial distribution of HIV seroprevalence, viremia prevalence, and number of unsuppressed adults often differed substantially within the same countries. The 1% and 5% of PLHIV with the highest VL on average accounted for 34% and 66%, respectively, of countries' total VL. HIV transmission ratios varied widely across countries and were higher for male-to-female (range: 2.3-28.3/100 PY) than for female-to-male transmission (range: 1.5-10.6/100 PY). In all countries mean log10 VL among unsuppressed males was higher than that among females. Correlations between VL measures and incident HIV varied, were weaker for VL metrics among females compared to males and were strongest for the number of unsuppressed PLHIV per 100 HIV-negative adults (R2 = 0.92)., Conclusions: Despite higher proportions of viral suppression, female unsuppressed PLHIV outnumbered males in all countries examined. Unsuppressed male PLHIV have consistently higher VL and a higher risk of transmitting HIV than females. Just 5% of PLHIV account for almost two-thirds of countries' total VL. Population-level VL metrics help monitor the epidemic and highlight key programmatic gaps in these African countries., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Nationally representative surveys provide an opportunity to assess trends in recent human immunodeficiency virus (HIV) infection based on assays for recent HIV infection. We assessed HIV incidence in Kenya in 2018 and trends in recent HIV infection among adolescents and adults in Kenya using nationally representative household surveys conducted in 2007, 2012, and 2018. To assess trends, we defined a recent HIV infection testing algorithm (RITA) that classified as recently infected (<12 months) those HIV-positive participants that were recent on the HIV-1 limiting antigen (LAg)-avidity assay without evidence of antiretroviral use. We assessed factors associated with recent and long-term (≥12 months) HIV infection versus no infection using a multinomial logit model while accounting for complex survey design. Of 1,523 HIV-positive participants in 2018, 11 were classified as recent. Annual HIV incidence was 0.14% in 2018 [95% confidence interval (CI) 0.057-0.23], representing 35,900 (95% CI 16,300-55,600) new infections per year in Kenya among persons aged 15-64 years. The percentage of HIV infections that were determined to be recent was similar in 2007 and 2012 but fell significantly from 2012 to 2018 [adjusted odds ratio (aOR) = 0.31, p  < .001]. Compared to no HIV infection, being aged 25-34 versus 35-64 years (aOR = 4.2, 95% CI 1.4-13), having more lifetime sex partners (aOR = 5.2, 95% CI 1.6-17 for 2-3 partners and aOR = 8.6, 95% CI 2.8-26 for ≥4 partners vs. 0-1 partners), and never having tested for HIV (aOR = 4.1, 95% CI 1.5-11) were independently associated with recent HIV infection. Although HIV remains a public health priority in Kenya, HIV incidence estimates and trends in recent HIV infection support a significant decrease in new HIV infections from 2012 to 2018, a period of rapid expansion in HIV diagnosis, prevention, and treatment.

Background: Increased coagulation biomarkers are associated with poor outcomes among people living with HIV (PLHIV). There are few data available from African cohorts demonstrating the effect of antiretroviral therapy (ART) on coagulation biomarkers., Methods: From March 2014 to October 2014, ART-naïve PLHIV initiating non-nucleoside reverse transcriptase inhibitor-based ART were recruited from seven clinics in western Kenya and followed for up to 12 months. Demographics, clinical history and blood specimens were collected. Logistic regression models adjusted for intrasite clustering examined associations between HIV viral load and D-Dimer at baseline. Mixed linear effects models were used to estimate mean change from baseline to 6 months overall, and by baseline viral load, sex and TB status at enrollment. Mean change in D-dimer at 6 months is reported on the log10 scale and as percentage change from baseline., Results: Among 611 PLHIV enrolled, 66% were female, median age was 34 years (interquartile range (IQR) 29-43 years), 31 (5%) participants had tuberculosis and median viral load was 113,500 copies/mL (IQR: 23,600-399,000). At baseline, 311 (50.9%) PLHIV had elevated D-dimer (> 500 ng/mL) and median D-dimer was 516.4 ng/mL (IQR: 302.7-926.6) (log baseline D-dimer: 2.7, IQR: 2.5-3.0). Higher baseline D-dimer was significantly associated with higher viral load (p < 0.0001), female sex (p = 0.02) and tuberculosis (p =  0.02). After 6 months on ART, 518 (84.8%) PLHIV had achieved viral load < 1000 copies/mL and median D-dimer was 390.0 (IQR: 236.6-656.9) (log D-dimer: 2.6, IQR: 2.4-2.8). Mean change in log D-dimer from baseline to 6 months was - 0.12 (95%CI -0.15, - 0.09) (p < 0.0001) indicating at 31.3% decline (95%CI -40.0, - 23.0) in D-dimer levels over the first 6 months on ART. D-dimer decline after ART initiation was significantly greater among PLHIV with tuberculosis at treatment initiation (- 172.1, 95%CI -259.0, - 106.3; p < 0.0001) and those with log viral load > 6.0 copies/mL (- 91.1, 95%CI -136.7, - 54.2; p < 0.01)., Conclusions: In this large Kenyan cohort of PLHIV, women, those with tuberculosis and higher viral load had elevated baseline D-dimer. ART initiation and viral load suppression among ART-naïve PLHIV in Kenya were associated with significant decrease in D-dimer at 6 months in this large African cohort.

Background and Objective: PRECISE is a population-based, prospective pregnancy cohort study designed for deep phenotyping of pregnancies in women with placenta-related disorders, and in healthy controls. The PRECISE Network is recruiting ~ 10,000 pregnant women in three countries (The Gambia, Kenya, and Mozambique) representing sub-Saharan Africa. The principal aim is to improve our understanding of pre-eclampsia, fetal growth restriction and stillbirth. This involves the creation of a highly curated biorepository for state of the art discovery science and a rich database of antenatal variables and maternal and neonatal outcomes. Our overarching aim is to provide large sample numbers with adequate power to address key scientific questions. Here we describe our experience of establishing a biorepository in the PRECISE Network and review the issues and challenges surrounding set-up, management and scientific use., Methods: The feasibility of collecting and processing each sample type was assessed in each setting and plans made for establishing the necessary infrastructure. Quality control (QC) protocols were established to ensure that biological samples are 'fit-for-purpose'. The management structures required for standardised sample collection and processing were developed. This included the need for transport of samples between participating countries and to external academic/commercial institutions., Results: Numerous practical challenges were encountered in setting up the infrastructure including facilities, staffing, training, cultural barriers, procurement, shipping and sample storage. Whilst delaying the project, these were overcome by establishing good communication with the sites, training workshops and constant engagement with the necessary commercial suppliers. A Project Executive Committee and Biology Working Group together defined the biospecimens required to answer the research questions paying particular attention to harmonisation of protocols with other cohorts so as to enable cross-biorepository collaboration. Governance structures implemented include a Data and Sample Committee to ensure biospecimens and data will be used according to consent, and prioritisation by scientific excellence. A coordinated sample and data transfer agreement will prevent delay in sample sharing., Discussion: With adequate training and infrastructure, it is possible to establish high quality sample collections to facilitate research programmes such as the PRECISE Network in sub-Saharan Africa. These preparations are pre-requisites for effective execution of a biomarker-based approach to better understand the complexities of placental disease in these settings, and others.

Background: Retention of mothers and infants across the prevention of mother-to-child HIV transmission (PMTCT) continuum remains challenging. We assessed the effectiveness of a lay worker administered combination intervention compared with the standard of care (SOC) on mother-infant attrition., Methods: HIV-positive pregnant women starting antenatal care at 10 facilities in western Kenya were randomized using simple randomization to receive individualized health education, retention/adherence support, appointment reminders, and missed visit tracking vs. routine care per guidelines. The primary endpoint was attrition of mother-infant pairs at 6 months postpartum. Attrition was defined as the proportion of mother-infant pairs not retained in the clinic at 6 months postpartum because of mother or infant death or lost to follow-up. Intent-to-treat analysis was used to assess the difference in attrition. This trial is registered with ClinicalTrials.gov; NCT01962220., Results: From September 2013 to June 2014, 361 HIV-positive pregnant women were screened, and 340 were randomized to the intervention (n = 170) or SOC (n = 170). Median age at enrollment was 26 years (interquartile range 22-30); median gestational age was 24 weeks (interquartile range 17-28). Overall attrition of mother-infant pairs was 23.5% at 6 months postpartum. Attrition was significantly lower in the intervention arm compared with SOC (18.8% vs. 28.2%, relative risk (RR) = 0.67, 95% confidence interval: 0.45 to 0.99, P = 0.04). Overall, the proportion of mothers who were retained and virally suppressed (<1000 copies/mL) at 6 months postpartum was 54.4%, with no difference between study arms., Conclusions: Provision of a combination intervention by lay counselors can decrease attrition along the PMTCT cascade in low-resource settings.

Introduction: Directed fibroblast migration is central to highly proliferative processes in regenerative medicine and developmental biology. However, the mechanisms by which single fibroblasts affect each other's directional decisions, while chemotaxing in microscopic pores, are not well understood., Methods: We explored effects of cell sequence and mitosis on fibroblast platelet-derived growth factor-BB (PDGF-BB)-induced migration in microfluidic mazes with two possible through paths: short and long. Additionally, image-based modeling of the chemoattractant's diffusion, consumption and decay, was used to explain the experimental observations., Results: It both cases, the cells displayed behavior that is contradictory to expectation based on the global chemoattractant gradient pre-established in the maze. In case of the sequence, the cells tend to alternate when faced with a bifurcation: if a leading cell takes the shorter (steeper gradient) path, the cell following it chooses the longer (weaker gradient) path, and vice versa. Image-based modeling of the process showed that the local PDGF-BB consumption by the individual fibroblasts may be responsible for this phenomenon. Additionally, it was found that when a mother cell divides, its two daughters go in opposite directions (even if it means migrating against the chemoattractant gradient and overcoming on-going cell traffic)., Conclusions: It is apparent that micro-confined fibroblasts modify each other's directional decisions in a manner that is counter-intuitive to what is expected from classical chemotaxis theory. Consequently, accounting for these effects could lead to a better understanding of tissue generation in vivo , and result in more advanced engineered tissue products in vitro ., (© Biomedical Engineering Society 2018.)

Background: The recent scale-up of prevention of mother-to-child transmission of HIV (PMTCT) services has rapidly accelerated antiretroviral therapy (ART) uptake among pregnant and postpartum women in sub-Saharan Africa. The Mother and Infant Retention for Health (MIR4Health) study evaluates the impact of a combination intervention administered by trained lay health workers to decrease attrition among HIV-positive women initiating PMTCT services and their infants through 6 months postpartum., Methods: This was a qualitative study nested within the MIR4Health trial. MIR4Health was conducted at 10 health facilities in Nyanza, Kenya from September 2013 to September 2015. The trial intervention addressed behavioral, social, and structural barriers to PMTCT retention and included: appointment reminders via text and phone calls, follow-up and tracking for missed clinic visits, PMTCT health education at home visits and during clinic visits, and retention and adherence support and counseling. All interventions were administered by lay health workers. We describe results of a nested small qualitative inquiry which conducted two focus groups to assess the experiences and perceptions of lay health workers administering the interventions. Discussions were recorded and simultaneously transcribed and translated into English. Data were analyzed using framework analysis approach., Results: Study findings show lay health workers played a critical role supporting mothers in PMTCT services across a range of behavioral, social, and structural domains, including improved communication and contact, health education, peer support, and patient advocacy and assistance. Findings also identified barriers to the uptake and implementation of the interventions, such as concerns about privacy and stigma, and the limitations of the healthcare system including healthcare worker attitudes. Overall, study findings indicate that lay health workers found the interventions to be feasible, acceptable, and well received by clients., Conclusions: Lay health workers played a fundamental role in supporting mothers engaged in PMTCT services and provided valuable feedback on the implementation of PMTCT interventions. Future interventions must include strategies to ensure client privacy, decrease stigma within communities, and address the practical limitations of health systems. This study adds important insight to the growing body of research on lay health worker experiences in HIV and PMTCT care., Trial Registration: Clinicaltrials.gov NCT01962220 .

Background: Effective retention of HIV-infected mothers and their infants is fraught with multiple challenges, resulting in loss across the continuum of prevention of mother-to-child HIV transmission (PMTCT) care and missed opportunities to offer life-saving HIV prevention and treatment., Methods: The Mother Infant Retention for Health study is an individual-randomized study evaluating the effectiveness of active patient follow-up compared with standard of care on the combined outcome of attrition of HIV-infected women and their infants at 6 months postpartum. Lay counselors administered the active patient follow-up package of interventions, including individualized health education, use of flip charts during clinic visits, and at home, phone and short message service appointment reminders, active phone and physical tracking of patients immediately after missed clinic visits, and individualized retention and adherence support., Results: Use of study visits to indicate participant progression along the PMTCT cascade highlights the nature of loss among women and infants in PMTCT care because of issues such as pregnancy complications, infant deaths, and transfer out. Delay in implementation of Option B+, unanticipated slow enrollment, a health-care worker strike, rapid HIV test kit shortages, and changes in national PMTCT guidelines necessitated several modifications to the protocol design and implementation to ensure successful completion of the study., Conclusions: Flexibility when operationalizing an implementation science study is critical in the context of the shifting landscape in a noncontrolled "real-world" setting., Trial Registration: Clinicaltrials.gov NCT01962220., Competing Interests: The authors have no conflicts of interest to disclose.

Given the burden of HIV and the critical shortage of health workers in Kenya, in 2011 the National AIDS and STI Control Program recommended shifting HIV care and treatment tasks to nurses in settings without physicians and clinical officers in order to decentralize and scale-up HIV services. In September 2013, ICAP at Columbia University conducted a survey with nurses in four health facilities in eastern Kenya to assess preparedness for task shifting. Findings indicated gaps in nurses' training, perceived competency, and practice in HIV care and treatment. Further investment in nurse capacity building is needed to bridge the gaps and prepare more nurses to provide high-quality, comprehensive HIV care and treatment services to curb the epidemic in Kenya., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

The centrality of quality as a strategy to achieve impact within the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) has been widely recognized. However, monitoring program quality remains a challenge for many HIV programs, particularly those in resource-limited settings, where human resource constraints and weaker health systems can pose formidable barriers to data collection and interpretation. We describe the practicalities of monitoring quality at scale within a very large multicountry PEPFAR-funded program, based largely at health facilities. The key elements include the following: supporting national programs and strategies; developing a conceptual framework and programmatic model to define quality and guide the provision of high-quality services; attending to program context, as well as program outcomes; leveraging existing and routinely collected data whenever possible; developing additional indicators for judicious use in targeted, in-depth assessments; providing hands-on support for data collection and use at the facility, sub-national, and national levels; utilizing web-based databases for data entry, analysis, and dissemination; and multidisciplinary support from a large team of clinical and strategic information advisors., Competing Interests: There are no conflicts of interest.

Objective: To evaluate if systemic murine malarial infection enhances HIV susceptibility through parasite-induced mucosal immune alterations at sites of HIV sexual exposure., Background: Malaria and HIV have a high degree of geographical overlap and interact substantially within coinfected individuals. We used a murine model to test the hypothesis that malaria might also enhance HIV susceptibility at mucosal sites of HIV sexual exposure., Methods: Female C57/BL6 mice were infected with Plasmodium chabaudi malaria using a standardized protocol. Blood, gastrointestinal tissues, upper and lower genital tract tissues, and iliac lymph nodes were sampled 10 days postinfection, and the expression of putative HIV susceptibility and immune activation markers on T cells was assessed by flow cytometry., Results: P. chabaudi malaria increased expression of mucosal homing integrin α4β7 on blood CD4 and CD8 T cells, and these α4β7 T cells had significantly increased co-expression of both CCR5 and CD38. In addition, malaria increased expression of the HIV co-receptor CCR5 on CD4 T cells from the genital tract and gut mucosa as well as mucosal T-cell expression of the immune activation markers CD38, Major Histocompatibility Complex -II (MHC-II) and CD69., Conclusions: Systemic murine malarial infection induced substantial upregulation of the mucosal homing integrin α4β7 in blood as well as gut and genital mucosal T-cell immune activation and HIV co-receptor expression. Human studies are required to confirm these murine findings and to examine whether malarial infection enhances the sexual acquisition of HIV.

Mucosal Th17 cells maintain the gut epithelial barrier and prevent invasion by luminal bacteria through a delicate balance of immunosuppressive and proinflammatory functions. HIV infection is characterized by mucosal Th17 depletion, microbial translocation, and immune activation. Therefore, we assessed the function of blood and sigmoid Th17 cells during both early and chronic HIV infection, as well as the impact of short- and long-term antiretroviral therapy. Th17 cells were defined as IL-17a(+) CD4 T cells, and their functional capacity was assessed by the coproduction of the inflammatory cytokines IL-22, TNF-α, and IFN-γ, as well as the immunoregulatory cytokine IL-10. Gut Th17 cells had a much greater capacity to produce proinflammatory cytokines than did those from the blood, but this capacity was dramatically reduced from the earliest stages of HIV infection. Immunoregulatory skewing of mucosal Th17 cell function, characterized by an increased IL-10/TNF-α ratio, was uniquely seen during early HIV infection and was independently associated with reduced systemic immune activation. Antiretroviral therapy rapidly restored mucosal Th17 cell numbers; however, normalization of mucosal Th17 function, microbial translocation, and mucosal/systemic immune activation was much delayed. These findings emphasize that strategies to preserve or to more rapidly restore mucosal Th17 function may have important therapeutic benefit.

Objectives: Although antiretroviral therapy (ART) prolongs life and reduces infectiousness, in some contexts, it has been associated with increased sexual risk taking., Design: Retrospective case-control study., Setting: Nairobi-based dedicated female sex worker (FSW) clinic., Participants: HIV-infected FSWs before and after ART initiation (n=62); HIV-infected and -uninfected control FSWs not starting ART during the same follow-up period (n=40)., Intervention: Initiation of ART., Primary Outcome Measures: Self-reported condom use, client numbers and sexually transmitted infection incidence over the study period (before and after ART initiation in cases)., Results: Sexual risk-taking behaviour with casual clients did not increase after ART initiation; condom use increased and sexually transmitted infection incidence decreased in both cases and controls, likely due to successful cohort-wide HIV prevention efforts., Conclusions: ART provision was not associated with increases in unsafe sex in this FSW population.

Background: Highly active antiretroviral therapy (HAART) dramatically reduces plasma HIV-1 viremia. However, despite completely suppressive HAART, it has been suggested that low-levels of viral replication may persist in the gut mucosa and elsewhere in individuals on long-term HAART., Objective: We conducted a double-blind randomized, placebo-controlled trial evaluating whether intensification of HAART in long-term virologically suppressed individuals with raltegravir is associated with a reduction in the level of proviral HIV-1 DNA in CD4(+) T cells in blood and the sigmoid colon (gut)., Methods: Long-term (>4 years) virologically suppressed HIV-infected individuals on standard HAART were randomized 1 : 1 in a double-blind fashion to receive raltegravir (400  mg twice/day) or placebo for 48 weeks. After week 48, all participants were treated with raltegravir to week 96. Blood and sigmoid biopsies were sampled and the frequency of CD4(+) T cells carrying HIV-1 proviral DNA was determined., Results: Twenty-four study patients were recruited. At 48 weeks, no difference was apparent between participants receiving raltegravir or placebo in blood HIV-1 proviral levels (P = 0.62), CD4(+) T-cell counts (P = 0.25) and gut proviral loads (P = 0.74). Similarly, prolonged raltegravir intensification up to week 96 had no further effect on both blood and gut HIV-1 proviral loads and blood CD4(+) T-cell counts., Conclusion: In long-term virologically suppressed patients on standard HAART, intensification with raltegravir did not result in further decay of CD4(+) T cells carrying HIV-1 proviral DNA in either the blood or gut after 48 or 96 weeks of therapy, or in any increase in CD4(+) T-cell counts.

Background: Identifying the immune correlates of reduced susceptibility to HIV remains a key goal for the HIV vaccine field, and individuals who are HIV-exposed, seronegative (HESN) may offer important clues. Reduced systemic immune activation has been described in HESN individuals. Conversely, pro-inflammatory T cell subsets, particularly CD4+ T cells producing the cytokine IL17 (Th17 cells), may represent a highly susceptible target for HIV infection after sexual exposure. Therefore, we characterized the cellular pro-inflammatory and IL17/IL22 cytokine immune milieu in the genital mucosa and blood of HESN female sex workers (FSWs)., Methods and Results: Blinded lab personnel characterized basal and mitogen-induced gene and cytokine immune responses in the cervix and blood of HESN FSWs (n = 116) and non-FSW controls (n = 17) using qPCR and ELISA. IL17 and IL22 production was significantly reduced in both the cervix and blood of HESNs, both in resting cells and after mitogen stimulation. In addition, HESN participants demonstrated blunted production of both pro-inflammatory cytokines and β-chemokines., Discussion and Conclusions: We conclude that HIV exposure without infection was associated with blunted IL17/IL22 and pro-inflammatory responses, both systemically and at the site of mucosal HIV exposure. It will be important for further studies to examine the causal nature of the association and to define the cell subsets responsible for these differences.

The HIV pandemic disproportionately affects women, with most infections acquired through receptive vaginal sex. Although the target cells by which HIV establishes infection in the female genital tract remain poorly defined, it is known that immune activation results in CD4(+) T cells with enhanced susceptibility, as does expression of the mucosal integrin α4β7 and the HIV coreceptor CCR5. Blood and cervical cytobrush specimens were collected from female sex workers (FSWs) in Nairobi, Kenya. Genital infection diagnostics were performed, T cell populations were defined by multiparameter flow cytometry based on their expression of surface receptors relevant to mucosal homing and/or HIV acquisition, and cytokine production was assayed by intracellular cytokine staining. The integrin α4β7 was expressed on 26.0% of cervical CD4(+) T cells, and these cells were more likely to express both the HIV coreceptor CCR5 (p < 0.0001) and the early activation marker CD69 (p < 0.0001) but not CXCR4 (p = 0.34). Cervical Th17 frequencies were enhanced compared with blood (7.02 versus 1.24%; p < 0.0001), and cervical IL-17A(+) CD4(+) T cells preferentially coexpressed α4β7 and CCR5. Expression of IFN-γ and IL-22 was greater in cervical Th17 cells than in blood Th17 cells. In keeping with the hypothesis that these cells are preferential HIV targets, gp120 preferentially bound CCR5(+) cervical T cells, and cervical Th17 cells were almost completely depleted in HIV(+) FSWs compared with HIV(-) FSWs. In summary, a subset of Th17 CD4(+) T cells in the cervical mucosa coexpresses multiple HIV susceptibility markers; their dramatic depletion after HIV infection suggests that these may serve as key target cells during HIV transmission.

Objective: Th17 cells play an important role in mucosal defence and repair and are highly susceptible to infection by HIV. Antiretroviral therapy (ART) suppresses HIV viremia and can restore CD4(+) numbers in the blood and gastrointestinal mucosa, but the resolution of systemic inflammation and gut microbial translocation is often incomplete. We hypothesized that this might relate to persistent dysregulation of gut CD4(+) Th17 subsets., Methods: Blood and sigmoid biopsies were collected from HIV-uninfected men, chronically HIV-infected, ART-naive men, and men on effective ART for more than 4 years. Sigmoid provirus levels were assayed blind to participant status, as were CD4(+) Th17 subsets, systemic markers of microbial translocation, and cellular immune activation., Results: There was minimal CD4(+) Th17 dysregulation in the blood until later stage HIV infection, but gastrointestinal Th17 depletion was apparent much earlier, along with increased plasma markers of microbial translocation. Plasma lipopolysaccharide (LPS) remained elevated despite overall normalization of sigmoid Th17 populations on long-term ART, although there was considerable interindividual variability in Th17 reconstitution. An inverse correlation was observed between plasma LPS levels and gut Th17 frequencies, and higher plasma LPS levels correlated with an increased gut HIV proviral reservoir., Conclusion: Sigmoid Th17 populations were preferentially depleted during HIV infection. Despite overall CD4(+) T-cell reconstitution, sigmoid Th17 frequencies after long-term ART were heterogeneous and higher frequencies were correlated with reduced microbial translocation.

Despite tremendous regional and subregional disparities in HIV prevalence around the world, epidemiology consistently demonstrates that black communities have been disproportionately affected by the pandemic. There are many reasons for this, and a narrow focus on socio-behavioural causes may be seen as laying blame on affected communities or individuals. HIV sexual transmission is very inefficient, and a number of biological factors are critical in determining whether an unprotected sexual exposure to HIV results in productive infection. This review will focus on ways in which biology, rather than behaviour, may contribute to regional and racial differences in HIV epidemic spread. Specific areas of focus are viral factors, host genetics, and the impact of co-infections and host immunology. Considering biological causes for these racial disparities may help to destigmatize the issue and lead to new and more effective strategies for prevention., (© 2011 John Wiley & Sons A/S.)

Several candidate HIV vaccines aim to induce virus-specific cellular immunity particularly in the genital tract, typically the initial site of HIV acquisition. However, standardized and sensitive methods for evaluating HIV-specific immune responses at the genital level are lacking. Therefore we evaluated real-time quantitative PCR (qPCR) as a potential platform to measure these responses. β-Actin and GAPDH were identified as the most stable housekeeping reference genes in peripheral blood mononuclear cells (PBMCs) and cervical mononuclear cells (CMCs) respectively and were used for normalizing transcript mRNA expression. HIV-specific cellular T cell immune responses to a pool of optimized CD8+ HIV epitopes (HIV epitope pool) and Staphylococcal enterotoxin B (SEB) superantigen control were assayed in HIV infected PBMC by qPCR, with parallel assessment of cytokine protein production. Peak HIV-specific mRNA expression of IFNγ, IL-2 and TNFα occurred after 3, 5 and 12 hours respectively. PBMCs were titrated to cervical appropriate cell numbers to determine minimum required assay input cell numbers; qPCR retained sensitivity with input of at least 2.5×10(4) PBMCs. This optimized qPCR assay was then used to assess HIV-specific cellular T cell responses in cytobrush-derived cervical T cells from HIV positive individuals. SEB induced IFNγ mRNA transcription was detected in CMCs and correlated positively with IFNγ protein production. However, qPCR was unable to detect HIV-induced cytokine mRNA production in the cervix of HIV-infected women despite robust detection of gene induction in PBMCs. In conclusion, although qPCR can be used to measure ex vivo cellular immune responses to HIV in blood, HIV-specific responses in the cervix may fall below the threshold of qPCR detection. Nonetheless, this platform may have a potential role in measuring mitogen-induced immune responses in the genital tract.

We examined the role of CD4(+) T cell IL-21 production in viral control of HIV infection. HIV-infected individuals had greater circulating IL-21-producing CD4(+) T cells in blood compared with uninfected volunteers. HIV-specific IL-21-producing CD4(+) T cells were detected in blood during untreated acute and chronic HIV infection, and elevated frequencies of these cells correlated with relative viral control. These cells had an effector memory or end effector phenotype and expressed CXCR5. HIV-specific CD8(+) T cells exhibited high levels of IL-21R, indicating sensitivity to IL-21. Low or aviremic long-term nonprogressors, however, showed absent or low HIV-specific IL-21 CD4(+) T cells, but more easily detectable HIV-specific IL-2-producing CD4(+) T cells, suggesting changing requirements for particular gamma-chain cytokines depending on Ag abundance. Thus, IL-21-producing CD4(+) T cells are induced in viremic HIV infection and likely contribute to viral control by affecting CD8(+) T cell maintenance.

Problem: Previously we reported that ovariectomized (OVX) mice receiving estradiol (E) prior to immunization with an attenuated strain of HSV-2 (TK-HSV-2) were not protected. Lack of protection in the E group was because of the inability of TK-HSV-2 to penetrate the thick keratinized epithelium. In this study, we determined the outcome of immunization after the thickening of vaginal epithelium following E-treatment waned. OVX, C57BL/6 mice were given Progesterone (P), E or saline (S) for 3 days and immunized with IVAG TK-HSV-2., Method of Study: To determine the time point at which E-treated mice could be successfully immunized, the mice were inoculated with TK-HSV-2 between days 1 and 7 (ED1-ED7) post-E-treatment and challenged with IVAG HSV-2 three weeks later., Results: The level of infection post-immunization correlated with HSV-2-specific IgG antibody level, which correlated with sterile protection. No viral infection was observed in ED1-ED3 groups and no specific antibodies were detected, resulting in no protection. Moderate infection was seen in ED5 group, resulting in low antibody production and non-sterile protection in 87.5% of mice. High antibody titers and sterile protection were observed in all groups that experienced robust infection post-immunization., Conclusion: The results show that estradiol leads to limited viral replication and diminished mucosal IgG response, resulting in non-sterile immune protection against genital herpes infection.

Chronic infection by herpes simplex virus type 2 (HSV-2) increases HIV susceptibility, perhaps due to HSV-2-associated increases in activated mucosal immune cells. A small number of Kenyan female sex workers (FSWs) exhibit relative HIV resistance. We examined whether relative HIV resistance was related to differences in the prevalence or mucosal immune impact of HSV-2. Participants were recruited from an open cohort of HIV-uninfected FSWs in Nairobi, Kenya. Women who had been practicing sex work in the cohort for >or=3 years without acquiring HIV were defined as relatively HIV resistant. HSV-2 diagnostics were performed, and cervical immune cell subsets were examined by flow cytometry in a subset of participants. The study population comprised 139 HIV-uninfected FSWs. HSV-2 seroprevalence was actually higher in FSWs meeting criteria for relative HIV resistance than in non-resistant FSWs (75/80, 94% vs 46/59, 78%; LR = 7.5; P = 0.006), likely due to the increased age and longer duration of sex work in the resistant subgroup. Late HIV acquisition was not associated with recent HSV-2 infection, and HSV-2 associated increases in HIV-susceptible cervical immune cell populations were similar in both groups. Relative HIV resistance in Kenyan FSWs was not due to a reduced prevalence or mucosal immune impact of HSV-2 infection.