Differential Burden of HIV Among Adolescent Girls and Young Women by Places Associated With Sex Work: An Observational Study in Mombasa, Kenya.

BACKGROUND: The design of HIV prevention programs for adolescent girls and young women (AGYW) are informed by data on who is at highest risk and where they can be reached. Places (hotspots) associated with selling sex are an established outreach strategy for sex work (SW) programs but could be used to reach other AGYW at high risk. SETTING: This study took place in Mombasa, Kenya. METHODS: We conducted a cross-sectional, bio-behavioural survey among (N = 1193) sexually active AGYW aged 14-24 years recruited at hotspots. We compared HIV prevalence by subgroup (SW; transactional sex, TS; and non-transactional sex), stratified by hotspot type (venues and nonvenues). We examined whether associations between HIV prevalence and hotspot/subgroup remained after adjustment for individual-level risk factors, and estimated HIV prevalence ratio with and without adjustment for these individual-level factors. RESULTS: Overall HIV prevalence was 5.6%, 5.3% in venues and 7.3% in nonvenues. Overall SW HIV prevalence was 2-fold higher than among participants engaged in nontransactional sex. After adjusting for age and individual-level risk factors, HIV prevalence was 2.72 times higher among venue-based SWs (95% confidence interval: 1.56 to 4.85) and 2.11 times higher among nonvenue AGYW not engaged in SW (95% confidence interval: 0.97 to 4.30) compared with venue-based AGYW not engaged in SW. CONCLUSION: AGYW who sell sex remain at high risk of HIV across types of hotspots. The residual pattern of elevated HIV burden by AGWY subgroup and hotspot type suggests that unmeasured, network-level factors underscore differential risks. As such, hotspots constitute a "place" to reach AGYW at high risk of HIV.

HIV acquisition prior to entry into formal sex work: inference from next-generation viral sequencing.

OBJECTIVE: To infer the timing of HIV acquisition in relation to self-reported events in the sexual life course of adolescent girls and young women (AGYW) who self-identify as female sex workers (FSW) in Mombasa, Kenya. DESIGN: Next-generation viral sequencing of samples of AGYW living with HIV in the Transitions study, a cross-sectional bio-behavioural survey of AGYW aged 14-24 years in Mombasa, Kenya. METHOD: Dried blood spot specimens were collected from study participants ( n  = 37, all FSW). A portion of the HIV pol gene was sequenced using an in-house next-generation sequencing assay for HIV drug resistance mutation genotyping. Estimated time since infection (ETI) was inferred using the HIV EVO web-based tool ( https://hiv.biozentrum.unibas.ch/ETI/ ), and data on self-reported events were obtained from the survey. RESULTS: The median ETI among FSW was 3.4 (interquartile range = 1.7, 6.3) years, with a median ETI of 1.5 years prior to entry into formal sex work. We estimated that 74.1% (95% confidence interval = 53.7-88.9%) of participants living with HIV and who self-identified as FSW likely acquired HIV prior to self-identification as a sex worker. CONCLUSIONS: Findings suggest a large fraction of prevalent HIV infection among AGYW engaged in sex work stems from acquisition prior to entry into formal sex work. Current HIV prevention programs tailored for sex workers may miss key opportunities for HIV prevention as they are designed to reach women after entry into formal sex work, signaling a need for tailored programs to reach high-risk AGYW earlier on in their sexual life course.

Endocervical Regulatory T Cells Are Associated With Decreased Genital Inflammation and Lower HIV Target Cell Abundance.

Regulatory T cells (Tregs) play important roles in tissue homeostasis, but few studies have investigated tissue Tregs in the context of genital inflammation, HIV target cell density, and vaginal microbiota in humans. In women from Nairobi (n=64), the proportion of CD4+ CD25+ CD127low Tregs in the endocervix correlated with those in blood (r=0.31, p=0.01), with a higher Treg frequency observed in the endocervix (median 3.8 vs 2.0%, p<0.0001). Most Tregs expressed FOXP3 in both compartments, and CTLA-4 expression was higher on endocervical Tregs compared to blood (median 50.8 vs 6.0%, p<0.0001). More than half (34/62, 55%) of participants displayed a non-Lactobacillus dominant vaginal microbiota, which was not associated with endocervical Tregs or CD4+ T cell abundance. In a multivariable linear regression, endocervical Treg proportions were inversely associated with the number of elevated pro-inflammatory cytokines (p=0.03). Inverse Treg associations were also observed for specific cytokines including IL-1ß, G-CSF, Eotaxin, IL-1RA, IL-8, and MIP-1 ß. Higher endocervical Treg proportions were associated with lower abundance of endocervical CD4+ T cells (0.30 log10 CD4+ T cells per log10 Treg, p=0.00028), with a similar trend for Th17 cells (p=0.09). Selectively increasing endocervical Tregs may represent a pathway to reduce genital tract inflammation in women.

Rectal microbiota diversity in Kenyan MSM is inversely associated with frequency of receptive anal sex, independent of HIV status.

OBJECTIVE: Both HIV infection and identifying as MSM have been linked to altered rectal microbiota composition, but few studies have studied sexual behavioural associations with rectal microbiota within MSM. In addition, most rectal microbiota studies in MSM have been limited geographically to Europe and North America, and replication of findings in lower and middle-income countries is lacking. DESIGN: A cross-sectional study. METHODS: We enrolled MSM from Nairobi, Kenya, and determined their HIV/sexually transmitted infection status. Rectal specimens were obtained for 16s rRNA sequencing of the rectal microbiota, and sexual behaviour was characterized using a standardized questionnaire. Microbiome differences were modelled using nonparametric statistics, Bray-Curtis ecological distance metrics and analyses of differential taxa abundance. Multivariable linear regression was used to model HIV status and recent sexual activity as predictors of alpha diversity, controlling for a range of covariates. RESULTS: Alpha diversity was consistently lower in Kenyan HIV-infected MSM (n = 80), including those on antiretroviral therapy (ART) compared with HIV-uninfected MSM. A statistical trend was observed for clustering of HIV status by Prevotella or Bacteroides dominance (P = 0.13). Several taxa were enriched in HIV-positive men, including Roseburia, Lachnospira, Streptococcus and Granulicatella. Receptive anal sex with several types of sexual partners (paying, regular, casual) was associated with lower Chao1 and Simpson diversity, independent of HIV status, while HIV infection was associated lower Chao1 (P = 0.030) but not Simpson diversity (P = 0.49). CONCLUSION: Both HIV infection and sexual behaviour were associated with rectal microflora alpha diversity, in particular richness, but not Prevotella spp. dominance, in Kenyan MSM. Associations were more robust for sexual behaviour.

Sex Work Is Associated With Increased Vaginal Microbiome Diversity in Young Women From Mombasa, Kenya.

BACKGROUND: Although nonoptimal vaginal bacteria and inflammation have been associated with increased HIV risk, the upstream drivers of these phenotypes are poorly defined in young African women. SETTING: Mombasa, Kenya. METHODS: We characterized vaginal microbiome and cytokine profiles of sexually active young women aged 14-24 years (n = 168) in 3 study groups: those engaging in formal sex work, in transactional sex, and nonsex workers. Vaginal secretions were collected using self-inserted SoftCup, and assayed for cytokines and vaginal microbiome through multiplex ELISA and 16S rRNA sequencing, respectively. Epidemiological data were captured using a validated questionnaire. RESULTS: The median age of participants was 20 years (interquartile range: 18-22 years). Approximately two-thirds of young women (105/168) had vaginal microbial communities characterized by Gardnerella and/or Prevotella spp. dominance; a further 29% (49/168) were predominantly Lactobacillus iners. Microbiome clustering explained a large proportion of cytokine variation (>50% by the first 2 principal components). Age was not associated with vaginal microbial profiles in bivariable or multivariable analyses. Women self-identifying as sex workers had increased alpha (intraindividual) diversity, independent of age, recent sexual activity, HIV, and other sexually transmitted infections (beta = 0.47, 95% confidence interval: 0.05 to 0.90, P = 0.03). Recent sex (number of partners or sex acts last week, time since last vaginal sex) correlated with increased alpha diversity, particularly in participants who were not involved in sex work. CONCLUSION: Nonoptimal vaginal microbiomes were common in young Kenyan women and associated with sex work and recent sexual activity, but independent of age. Restoring optimal vaginal microflora may represent a useful HIV prevention strategy.

Mechanisms of sexually transmitted infection-induced inflammation in women: implications for HIV risk.

INTRODUCTION: Globally, sexually transmitted infections (STI) affect >300 million people annually, and are a major cause of sexual and reproductive health complications in women. In this commentary, we describe how STIs interact with the immune and non-immune cells, both within and below the cervicovaginal mucosal barrier, to cause inflammation, which in turn has been associated with increased HIV acquisition risk. DISCUSSION: STIs have a major impact on the female genital mucosa, which is an important biological and physical barrier that forms the first line of defence against invading microorganisms such as HIV. Pattern recognition of STI pathogens, by receptors expressed either on the cell surface or inside the cell, typically triggers inflammation at the mucosal barrier. The types of mucosal responses vary by STI, and can be asymptomatic or culminate in the formation of discharge, ulcers and/or warts. While the aim of this response is to clear the invading microbes, in many cases these responses are either evaded or cause pathology that impairs barrier integrity and increases HIV access to target cells in the sub-mucosa. In addition, innate responses to STIs can result in an increased number of immune cells, including those that are the primary targets of HIV, and may contribute to the association between STIs and increased susceptibility to HIV acquisition. Many of these cells are mediators of adaptive immunity, including tissue-resident cells that may also display innate-like functions. Bacterial vaginosis (BV) is another common cause of inflammation, and evidence for multiple interactions between BV, STIs and HIV suggest that susceptibility to these conditions should be considered in concert. CONCLUSIONS: STIs and other microbes can induce inflammation in the genital tract, perturbing the normal robust function of the mucosal barrier against HIV. While the impact of STIs on the mucosal immune system and HIV acquisition is often under-appreciated, understanding their interactions of the infections with the immune responses play an important role in improving treatment and reducing the risk of HIV acquisition. The frequent sub-clinical inflammation associated with STIs underscores the need for better STI diagnostics to reverse the immunological consequences of infection.

Integrin α4ß7 expression on peripheral blood CD4+ T cells predicts HIV acquisition and disease progression outcomes.

The gastrointestinal (GI) mucosa is central to HIV pathogenesis, and the integrin α4ß7 promotes the homing of immune cells to this site, including those that serve as viral targets. Data from simian immunodeficiency virus (SIV) animal models suggest that α4ß7 blockade provides prophylactic and therapeutic benefits. We show that pre-HIV infection frequencies of α4ß7+ peripheral blood CD4+ T cells, independent of other T cell phenotypes and genital inflammation, were associated with increased rates of HIV acquisition in South African women. A similar acquisition effect was observed in a Kenyan cohort and in nonhuman primates (NHPs) after intravaginal SIV challenge. This association was stronger when infection was caused by HIV strains containing V2 envelope motifs with a preference for α4ß7 binding. In addition, pre-HIV α4ß7+ CD4+ T cells predicted a higher set-point viral load and a greater than twofold increased rate of CD4+ T cell decline. These results were confirmed in SIV-infected NHPs. Increased frequencies of pre-HIV α4ß7+ CD4+ T cells were also associated with higher postinfection expression of lipopolysaccharide binding protein, a microbial translocation marker, suggestive of more extensive gut damage. CD4+ T cells expressing α4ß7 were rapidly depleted very early in HIV infection, particularly from the GI mucosa, and were not restored by early antiretroviral therapy. This study provides a link between α4ß7 expression and HIV clinical outcomes in humans, in line with observations made in NHPs. Given the availability of a clinically approved anti-α4ß7 monoclonal antibody for treatment of inflammatory bowel disease, these data support further evaluation of targeting α4ß7 integrin as a clinical intervention during HIV infection.

Co-Infection Burden of Hepatitis C Virus and Human Immunodeficiency Virus among Injecting Heroin Users at the Kenyan Coast.

BACKGROUND: Injection drug use is steadily rising in Kenya. We assessed the prevalence of both human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infections among injecting heroin users (IHUs) at the Kenyan Coast. METHODS: A total of 186 IHUs (mean age, 33 years) from the Omari rehabilitation center program in Malindi were consented and screened for HIV-1 and HCV by serology and PCR and their CD4 T-cells enumerated by FACS. RESULTS: Prevalence of HIV-1 was 87.5%, that of HCV was 16.4%, co-infection was 17.9% and 18/152 (11.8%) were uninfected. Only 5.26% of the HIV-1 negative injectors were HCV positive. Co-infection was higher among injectors aged 30 to 40 years (20.7%) and among males (22.1%) than comparable groups. About 35% of the injectors were receiving antiretroviral treatment (ART). Co-infection was highest among injectors receiving D4T (75%) compared to those receiving AZT (21.6%) or TDF (10.5%) or those not on ART (10.5%). Mean CD4 T-cells were 404 (95% CI, 365 - 443) cells/mm3 overall, significantly lower for co-infected (mean, 146; 95% CI 114 - 179 cells/mm3) than HIV mono infected (mean, 437, 95% CI 386 - 487 cells/mm3, p<0.001) or uninfected (mean, 618, 95% CI 549 - 687 cells/mm3, p<0.001) injectors and lower for HIV mono-infected than uninfected injectors (p=0.002). By treatment arm, CD4 T-cells were lower for injectors receiving D4T (mean, 78; 95% CI, 0.4 - 156 cells/mm3) than TDF (mean 607, 95% CI, 196 - 1018 cells/mm3, p=0.005) or AZT (mean 474, 95% CI -377 - 571 cells/mm3, p=0.004). CONCLUSION: Mono and dual infections with HIV-1 and HCV is high among IHUs in Malindi, but ART coverage is low. The co-infected IHUs have elevated risk of immunodeficiency due to significantly depressed CD4 T-cell numbers. Coinfection screening, treatment-as-prevention for both HIV and HCV and harm reduction should be scaled up to alleviate infection burden.

Implementation and Operational Research: Correlates of Adherence and Treatment Failure Among Kenyan Patients on Long-term Highly Active Antiretroviral Therapy.

BACKGROUND: Universal access to highly active antiretroviral therapy (HAART) is still elusive in most developing nations. We asked whether peer support influenced adherence and treatment outcome and if a single viral load (VL) could define treatment failure in a resource-limited setting. METHODS: A multicenter longitudinal and cross-sectional survey of VL, CD4 T cells, and adherence in 546 patients receiving HAART for up to 228 months. VL and CD4 counts were determined using m2000 Abbott RealTime HIV-1 assay and FACS counters, respectively. Adherence was assessed based on pill count and on self-report. RESULTS: Of the patients, 55.8%, 22.2%, and 22% had good, fair, and poor adherence, respectively. Adherence, peer support, and regimen, but not HIV disclosure, age, or gender, independently correlated with VL and durability of treatment in a multivariate analysis (P < 0.001). Treatment failure was 35.9% using sequential VL but ranged between 27% and 35% using alternate single VL cross-sectional definitions. More patients failed stavudine (41.2%) than zidovudine (37.4%) or tenofovir (28.8%, P = 0.043) treatment arms. Peer support correlated positively with adherence (χ(2), P < 0.001), with nonadherence being highest in the stavudine arm. VL before the time of regimen switch was comparable between patients switching and not switching treatment. Moreover, 36% of those switching still failed the second-line regimen. CONCLUSION: Weak adherence support and inaccessible VL testing threaten to compromise the success of HAART scale-up in Kenya. To hasten antiretroviral therapy monitoring and decision making, we suggest strengthening patient-focused adherence programs, optimizing and aligning regimen to WHO standards, and a single point-of-care VL testing when multiple tests are unavailable.

Genotypic Variability of HIV-1 Reverse Transcriptase Gene from Long-Term Antiretroviral-Experienced Patients in Kenya.

There is continuous need to track genetic profiles of HIV strains circulating in different geographic settings to hasten vaccine discovery and inform public health and intervention policies. We partially sequenced the reverse transcriptase region of the HIV-1 pol gene from a total of 54 Kenyan patients aged 18-56 years who continued highly active antiretroviral treatment (HAART) for between 8 and 102 months. Subtyping was done using both the JPHMM tool and phylogenetic method. HIV-1 subtype A1 was the predominant strain in circulation, representing 57.4% and 70.4% of all isolates as determined by JPHMM and phylogenetic methods, respectively. Subtypes D (14.8%, 7.4%), C (5.6%, 9.3%), and A2 (0%, 5.6%) were determined at respective prevalence by both methods. JPHMM identified 22.2% of the isolates as recombinants. This surveillance focused on the RT gene and reaffirms the predominance of subtype A and an increasing proportion of recombinant strains in the Kenyan epidemic.

HIV-1 subtype diversity based on envelope C2V3 sequences from Kenyan patients on highly active antiretroviral therapy.

There is a continuous need to genetically characterize the HIV strains in circulation in order to assess interventions and inform vaccine discovery. We partially sequenced the envelope C2V3 gene from a total of 59 Kenyan patients on highly active antiretroviral treatment (HAART) and determined HIV subtypes using both the JPHMM subtyping tool and the phylogenetic method. HIV-1 subtype A1 was the predominant strain in circulation, representing 65.5% and 74.5% of all isolates as determined by JPHMM and phylogenetic methods, respectively. Subtypes C and D were the next most prevalent pure strains at 9.1% each by both methods. JPHMM identified 9.1% of the isolates as recombinant. Four isolates had short sequences not covering the entire C2V3 region and were thus not subtyped. From this study, subtype A viruses are still the predominant HIV-1 strains in local circulation in Kenya. Constant surveillance is needed to update molecular trends under continuing HAART scale-up.