Developing and testing a web-based platform for antiretroviral therapy (ART) adherence support among adolescents and young adults (AYA) living with HIV.

Objective: Describe the development and testing of a web-based platform for antiretroviral treatment (ART) adherence support among HIV+ adolescents and young adults (AYA) in a randomized controlled trial (RCT). Methods: A seven-member multi-disciplinary team operationalized the flat, password protected, web-based platform. Manualized protocols guided the objectives and content for each of the eight web-based sessions. Team members evaluated usability and content validity. Client satisfaction and perceived ease of use was evaluated with the first ten HIV+ AYA participants. Results: The web-based platform was developed, evaluated, refined, implemented and pilot tested between September 2020 to April 2022. Usability was rated as high; the evaluation of content validity showed an excellent fit between session content and objectives. HIV+ AYA participants (mean age = 24.2 years) were satisfied with the quality, type, and amount of support/education received, and found the platform easy to use, operate, and navigate. Average time spent per session was 6.5 min. Conclusion: Findings support the usability, validity, acceptability, and feasibility of this web-based platform for ART adherence support among HIV+ AYA. Innovation: Our research and findings are responsive to research gaps and the need for transparency in the methodological development and testing of web-based control arms for ART adherence support among HIV+ AYA.

Feasibility and Acceptability of the Adherence Connection Counseling, Education, and Support (ACCESS) Proof of Concept: A Peer-Led, Mobile Health (mHealth) Cognitive Behavioral Antiretroviral Therapy (ART) Adherence Intervention for HIV-Infected (HIV+) Adolescents and Young Adults (AYA).

Effective antiretroviral therapy (ART) adherence strategies for HIV+ adolescents and young adults (AYA) are needed to prevent HIV-related morbidity, mortality, and onward transmission. In the Adherence Connection for Counseling, Education, and Support (ACCESS) pilot, an exploratory sequential mixed-methods design was used to develop and test a peer-led, mobile health (mHealth) cognitive behavioral ART adherence intervention. HIV+ AYA (ages 16-29 years) with unsuppressed plasma HIV RNA (HIV viral load) were eligible for this five-session intervention directed to improving ART adherence and HIV viral load. A total of 78 peer-led remote videoconferencing sessions (via WebEx) were delivered to 16 participants. High completion rates (97.5%) and client satisfaction scores (mean = 29.13 of 32; SD = 2.45) were observed. Self-reported ART adherence improved (32% increase in doses taken; 95th CI 11.2-53.3) with an annualized average rate of 47.5% (0.28 log10) reduction in HIV viral load. We established proof of concept for the ACCESS peer-led, mHealth cognitive behavioral ART adherence intervention, with promising adherence and virologic outcome data.

RESUMEN: Se necesitan estrategias efectivas de adherencia a la terapia antirretroviral (TAR) para adolescentes y adultos jóvenes (AAJ) VIH+ para prevenir la morbilidad, la mortalidad y las transmisiones futuras relacionadas con el VIH. En el proyecto piloto Adherence Connection for Counseling, Education, and Support (ACCESS), se utilizó un diseño exploratorio secuencial de métodos mixtos para desarrollar y testear una intervención de adherencia cognitiva conductual de salud móvil (mHealth) dirigida por pares a la TAR. AAJ VIH+ (de 16 a 29 años de edad) con ARN del VIH (carga viral del VIH) en plasma no suprimido fueron elegibles para esta intervención de cinco sesiones dirigida a mejorar la adherencia a la TAR y la carga viral del VIH. Se dictaron un total de 78 sesiones de videoconferencias remotas dirigidas por pares (a través de WebEx) a 16 participantes. Fueron observadas tasas altas de finalización (97.5%) y puntuaciones de satisfacción del cliente (media=29.13 de 32; SD=2.45). La adherencia autoinformada a la TAR mejoró (aumento del 32% en las dosis tomadas; IC del 95=11.2 a 53.3) con una tasa promedio anualizada de reducción en la carga viral del VIH del 47.5% (0.28 log 10). Establecimos una prueba de concepto para ACCESS, la intervención de adherencia a la TAR cognitivo conductual mHealth dirigida por pares, con datos prometedores sobre la adherencia y los resultados virológicos.

Restriction Factor Expression in Vertically Infected Children Living With HIV-1.

INTRODUCTION: Around 1.7 million children are estimated to live with HIV-1 worldwide, and about 160,000 infants are newly infected every year. Since adaptive immunity takes time to mature and develop in infants, and maternal antibodies provide limited antiviral activity, innate and intrinsic immunity against HIV-1 in the young is of critical importance. Intrinsic restriction factors are cellular proteins that effectively inhibit HIV-1 replication in vitro, but there is limited understanding of their role in vivo, and little to no data has been reported on the expression of host restriction factors in children. We hypothesized that restriction factor expression might be particularly important in children living with HIV-1 and correlate with disease progression. METHODS: We analyzed gene expression of APOBEC3A, APOBEC3C, APOBEC3G, APOBEC3H, SAMHD1, ISG15, CDKN1A, MX2, TRIM5, and SLFN11 by qPCR in 121 samples of CD4+ T cells from vertically infected children living with HIV-1. Cell surface expression of BST-2/tetherin and markers of CD4+ T-cell activation were analyzed by flow cytometry. RESULTS: After adjusting for gender and age, BST-2/tetherin expression on CD4+ T cells showed significant positive correlation with viral load (P = 0.0006; ρ = 0.33), CD4+ T-cell activation (P < 0.0001; ρ = 0.53), CD8+ T-cell activation (P < 0.0001; ρ = 0.53), and a negative correlation with CD4+ T-cell counts (P = 0.0008; ρ = -0.33). The expression of SAMHD1 correlated negatively with markers of T-cell activation (P = 0.046; ρ = -0.22). DISCUSSION: These results suggest an important role of some restriction factors in the pathogenesis of HIV-1 in children.

Internationally Acquired Severe Systemic Infections in Febrile Pediatric Travelers Presenting to the Emergency Department.

OBJECTIVES: Most children in the United States who visit the emergency department (ED) with fever have minor illnesses not requiring treatment or hospitalization. However, when a child has recently immigrated or traveled abroad, internationally acquired severe systemic infections (ISSIs) must be considered. We sought to describe children who have traveled internationally and present to the ED with a complaint of fever and to determine risk factors associated with ISSIs in these patients. METHODS: We conducted a retrospective study of children younger than 18 years who presented to 2 pediatric EDs in Bronx, NY (June 2007 to May 2017). Patients were included if they had both fever within 24 hours and international travel within 30 days. We compared groups using bivariate analyses and created a prediction model for ISSIs using multivariable logistic regression. RESULTS: Of the 353 children included, 44 (12%) had ISSI: 25 (57%), malaria; 6 (14%), dengue; and 13 (30%), bacteremia. Eight (18%) of those with ISSI presented with fever to another medical provider in the week prior but did not receive bloodwork. Four variables were independently associated with ISSIs: headache (odds ratio [OR], 21.7; 95% confidence interval [CI], 6.8-69.3), travel to Africa or Asia (OR, 18.8; 95% CI, 4.8-73.2), platelets of 150,000/µL or less (OR, 15.1; 95% CI, 4.7-48.6), and alanine aminotransferase level of 30 IU/L or greater (OR, 8.9; 95% CI, 3.1-25.3). CONCLUSIONS: Children who travel internationally and present with fever upon return are at substantial risk for developing ISSIs. The diagnosis of ISSIs is often overlooked, but certain risk factors have the potential to aid clinicians.

MAIT cells are activated in acute Dengue virus infection and after in vitro Zika virus infection.

Dengue virus (DENV) and Zika virus (ZIKV) are members of the Flaviviridae and are predominantly transmitted via mosquito bites. Both viruses are responsible for a growing number of infections in tropical and subtropical regions. DENV infection can cause lethargy with severe morbidity and dengue shock syndrome leading to death in some cases. ZIKV is now linked with Guillain-Barré syndrome and fetal malformations including microcephaly and developmental disorders (congenital Zika syndrome). The protective and pathogenic roles played by the immune response in these infections is unknown. Mucosal-associated invariant T (MAIT) cells are a population of innate T cells with potent anti-bacterial activity. MAIT cells have also been postulated to play a role in the immune response to viral infections. In this study, we evaluated MAIT cell frequency, phenotype, and function in samples from subjects with acute and convalescent DENV infection. We found that in acute DENV infection, MAIT cells had elevated co-expression of the activation markers CD38 and HLA-DR and had a poor IFNγ response following bacterial stimulation. Furthermore, we found that MAIT cells can produce IFNγ in response to in vitro infection with ZIKV. This MAIT cell response was independent of MR1, but dependent on IL-12 and IL-18. Our results suggest that MAIT cells may play an important role in the immune response to Flavivirus infections.

Antiretroviral therapy in HIV-infected adolescents: clinical and pharmacologic challenges.

INTRODUCTION: With the currently available combined antiretroviral therapy regimens, durable suppression of viral replication, preservation of immune function and normalizing life expectancy, are all becoming achievable goals. Teenagers and young adults living with HIV present unique clinical and pharmacologic challenges to optimizing antiretroviral treatment outcomes. Areas covered: In this expert review of the topic, we examine recent clinical trial data and draw on our program's 25 year experience working with both perinatally and behaviorally HIV infected adolescents. Expert commentary: In order to be effective, the antiretrovirals we provide must be combined with multidisciplinary interventions and ongoing socio-behavioral support to ensure treatment adherence and prevent the emergence of viral resistance.

T cells target APOBEC3 proteins in human immunodeficiency virus type 1-infected humans and simian immunodeficiency virus-infected Indian rhesus macaques.

APOBEC3 proteins mediate potent antiretroviral activity by hypermutating the retroviral genome during reverse transcription. To counteract APOBEC3 and gain a replicative advantage, lentiviruses such as human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) have evolved the Vif protein, which targets APOBEC3 proteins for proteasomal degradation. However, the proteasome plays a critical role in the generation of T cell peptide epitopes. Whether Vif-mediated destruction of APOBEC3 proteins leads to the generation and presentation of APOBEC3-derived T cell epitopes on the surfaces of lentivirus-infected cells remains unknown. Here, using peptides derived from multiple Vif-sensitive APOBEC3 proteins, we identified APOBEC3-specific T cell responses in both HIV-1-infected patients and SIV-infected rhesus macaques. These results raise the possibility that these T cell responses may be part of the larger antiretroviral immune response.

Impact of HIV-1 infection and pregnancy on maternal health: comparison between perinatally and behaviorally infected young women.

BACKGROUND: The introduction of combination antiretroviral therapy has resulted in improved survival and quality of life for individuals infected with the human immunodeficiency virus (HIV). There is, as expected, a growing population of perinatally HIV-infected women who are, have been, or will become pregnant. We describe a large cohort of perinatally infected women, compare it with a similar age-matched behaviorally HIV-infected group, and examine factors affecting maternal and infant health. METHODS: We reviewed the records of 30 perinatally infected women who gave birth at two hospitals between January 2000 and December 2011. The comparison group comprised behaviorally infected women who delivered at these hospitals during the same period. The outcome measures were differences in CD4 counts and viral load between the cohorts, and comparisons of maternal morbidity, mortality, and mother-to-child HIV transmission. RESULTS: Median CD4 counts were significantly lower in the perinatal group before, during, and after pregnancy. The median viral load was significantly higher in the perinatal group. Interval prepregnancy to post partum viral load decline was also greater in the behavioral group. Viral load decreases in the perinatal population were not sustained in the post partum period, at which time viral load trended back to prepregnancy levels. There was one mother-to-child HIV transmission in a perinatally infected woman. Over an extended 4 years of follow-up, there were four deaths in the perinatal group and none in the behavioral group. CONCLUSION: After delivery, the differences between perinatally and behaviorally infected mothers accentuate, with immunologic deterioration in the former group. The perinatal population may require novel management strategies to ensure outcomes comparable with those observed in the behavioral group.

Age-related expansion of Tim-3 expressing T cells in vertically HIV-1 infected children.

As perinatally HIV-1-infected children grow into adolescents and young adults, they are increasingly burdened with the long-term consequences of chronic HIV-1 infection, with long-term morbidity due to inadequate immunity. In progressive HIV-1 infection in horizontally infected adults, inflammation, T cell activation, and perturbed T cell differentiation lead to an "immune exhaustion", with decline in T cell effector functions. T effector cells develop an increased expression of CD57 and loss of CD28, with an increase in co-inhibitory receptors such as PD-1 and Tim-3. Very little is known about HIV-1 induced T cell dysfunction in vertical infection. In two perinatally antiretroviral drug treated HIV-1-infected groups with median ages of 11.2 yr and 18.5 yr, matched for viral load, we found no difference in the proportion of senescent CD28(-)CD57(+)CD8(+) T cells between the groups. However, the frequency of Tim-3(+)CD8(+) and Tim-3(+)CD4(+) exhausted T cells, but not PD-1(+) T cells, was significantly increased in the adolescents with longer duration of infection compared to the children with shorter duration of HIV-1 infection. PD-1(+)CD8(+) T cells were directly associated with T cell immune activation in children. The frequency of Tim-3(+)CD8(+) T cells positively correlated with HIV-1 plasma viral load in the adolescents but not in the children. These data suggest that Tim-3 upregulation was driven by both HIV-1 viral replication and increased age, whereas PD-1 expression is associated with immune activation. These findings also suggest that the Tim-3 immune exhaustion phenotype rather than PD-1 or senescent cells plays an important role in age-related T cell dysfunction in perinatal HIV-1 infection. Targeting Tim-3 may serve as a novel therapeutic approach to improve immune control of virus replication and mitigate age related T cell exhaustion.

HIV in the tropics: staging in the resource-limited setting.

PURPOSE OF REVIEW: In 2010, the WHO updated HIV treatment guidelines for adults and children, expanding the eligibility of HIV-infected individuals for antiretroviral therapy (ART) on the basis of immunological staging. We discuss the barriers to HIV staging in under-resourced settings. RECENT FINDINGS: In industrialized countries, HIV-infected patients are immunologically staged using CD4 lymphocyte counts measured using flow cytometry, but reliable and timely CD4 testing is still not readily available for all patients in many poorly resourced countries. Often CD4 testing is only available in central hospitals and clinics and depends upon availability of reagents. This leaves clinical staging as the standard of care in many places. Significant discrepancies exist between clinical and immunologic staging. Lack of immunologic staging can lead to delayed or inappropriate initiation of ART, increased attrition before ART, and overall poorer outcomes as patients often initiate ART at lower CD4 cell count baselines. This has led to intensive efforts to develop cost-effective laboratory testing, particularly for accurate low-cost CD4 testing. SUMMARY: Simplified, low-cost alternatives for immunologic staging are vital to continued scale up of ART programs globally. Point-of-care CD4 testing in particular has shown promise in decreasing attrition rates before ART and improving overall mortality in resource-limited settings.

Association of differentiation state of CD4+ T cells and disease progression in HIV-1 perinatally infected children.

BACKGROUND: In the USA, most HIV-1 infected children are on antiretroviral drug regimens, with many individuals surviving through adolescence and into adulthood. The course of HIV-1 infection in these children is variable, and understudied. METHODOLOGY/PRINCIPAL FINDINGS: We determined whether qualitative differences in immune cell subsets could explain a slower disease course in long term survivors with no evidence of immune suppression (LTS-NS; CD4%≥25%) compared to those with severe immune suppression (LTS-SS; CD4%≤15%). Subjects in the LTS-NS group had significantly higher frequencies of naïve (CCR7+CD45RA+) and central memory (CCR7+CD45RA-) CD4+ T cells compared to LTS-SS subjects (p = 0.0005 and <0.0001, respectively). Subjects in the rapid progressing group had significantly higher levels of CD4+ T(EMRA) (CCR7-CD45RA+) cells compared to slow progressing subjects (p<0.0001). CONCLUSIONS/SIGNIFICANCE: Rapid disease progression in vertical infection is associated with significantly higher levels of CD4+ T(EMRA) (CCR7-CD45RA+) cells.

Expansion of CD8+ T cells lacking Sema4D/CD100 during HIV-1 infection identifies a subset of T cells with decreased functional capacity.

Sema4D, also known as CD100, is a constitutively expressed immune semaphorin on T cells and NK cells. CD100 has important immune regulatory functions that improve antigen-specific priming by antigen-presenting cells, and can also act as a costimulatory molecule on T cells. We investigated the consequence of HIV-1 infection on CD100 expression by T cells, and whether CD100 expression signifies functionally competent effector cells. CD100 expression on T cells from healthy individuals was compared with HIV-1-infected subjects including elite controllers, noncontrollers, and patients receiving antiretroviral therapy. The frequency and fluorescence intensity of CD100 on CD8(+) and CD4(+) T cells were decreased during HIV-1 infection. Furthermore, the absolute number of CD100-expressing CD8(+) T cells was positively associated with the magnitude of HIV-1-specific T-cell responses. CD8(+) T cells lacking CD100 expression were functionally impaired and present in increased numbers in HIV-1-infected individuals. The number of CD100(-)CD8(+) T cells positively correlated with T-cell immunosenescence, immune activation, and viral load. Loss of CD100 expression appears to result from direct antigen stimulation, as in vitro cytokine exposure and viral replication did not significantly impact CD100 expression. These data suggest that loss of CD100 expression probably plays an important role in dysfunctional immunity in HIV-1 infection.

Identification of human endogenous retrovirus-specific T cell responses in vertically HIV-1-infected subjects.

Human endogenous retrovirus (HERV)-specific T cell responses in HIV-1-infected adults have been reported. Whether HERV-specific immunity exists in vertically HIV-1-infected children is unknown. We performed a cross-sectional analysis of HERV-specific T cell responses in 42 vertically HIV-1-infected children. HERV (-H, -K, and -L family)-specific T cell responses were identified in 26 of 42 subjects, with the greatest magnitude observed for the responses to HERV-L. These HERV-specific T cell responses were inversely correlated with the HIV-1 plasma viral load and positively correlated with CD4(+) T cell counts. These data indicate that HERV-specific T cells may participate in controlling HIV-1 replication and that certain highly conserved HERV-derived proteins may serve as promising therapeutic vaccine targets in HIV-1-infected children.

Immunodominance of HIV-1 specific CD8+ T-cell responses is related to disease progression rate in vertically infected adolescents.

BACKGROUND: HIV-1 vertically infected children in the USA are living into adolescence and beyond with the widespread use of antiretroviral drugs. These patients exhibit striking differences in the rate of HIV-1 disease progression which could provide insights into mechanisms of control. We hypothesized that differences in the pattern of immunodomination including breadth, magnitude and polyfunctionality of HIV-1 specific CD8+ T cell response could partially explain differences in progression rate. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we mapped, quantified, and assessed the functionality of these responses against individual HIV-1 Gag peptides in 58 HIV-1 vertically infected adolescents. Subjects were divided into two groups depending upon the rate of disease progression: adolescents with a sustained CD4%≥25 were categorized as having no immune suppression (NS), and those with CD4%≤15 categorized as having severe immune suppression (SS). We observed differences in the area of HIV-1-Gag to which the two groups made responses. In addition, subjects who expressed the HLA- B*57 or B*42 alleles were highly likely to restrict their immunodominant response through these alleles. There was a significantly higher frequency of naïve CD8+ T cells in the NS subjects (p = 0.0066) compared to the SS subjects. In contrast, there were no statistically significant differences in any other CD8+ T cell subsets. The differentiation profiles and multifunctionality of Gag-specific CD8+ T cells, regardless of immunodominance, also failed to demonstrate meaningful differences between the two groups. CONCLUSIONS/SIGNIFICANCE: Together, these data suggest that, at least in vertically infected adolescents, the region of HIV-1-Gag targeted by CD8+ T cells and the magnitude of that response relative to other responses may have more importance on the rate of disease progression than their qualitative effector functions.

Human endogenous retrovirus K106 (HERV-K106) was infectious after the emergence of anatomically modern humans.

HERV-K113 and HERV-K115 have been considered to be among the youngest HERVs because they are the only known full-length proviruses that are insertionally polymorphic and maintain the open reading frames of their coding genes. However, recent data suggest that HERV-K113 is at least 800,000 years old, and HERV-K115 even older. A systematic study of HERV-K HML2 members to identify HERVs that may have infected the human genome in the more recent evolutionary past is lacking. Therefore, we sought to determine how recently HERVs were exogenous and infectious by examining sequence variation in the long terminal repeat (LTR) regions of all full-length HERV-K loci. We used the traditional method of inter-LTR comparison to analyze all full length HERV-Ks and determined that two insertions, HERV-K106 and HERV-K116 have no differences between their 5' and 3' LTR sequences, suggesting that these insertions were endogenized in the recent evolutionary past. Among these insertions with no sequence differences between their LTR regions, HERV-K106 had the most intact viral sequence structure. Coalescent analysis of HERV-K106 3' LTR sequences representing 51 ethnically diverse individuals suggests that HERV-K106 integrated into the human germ line approximately 150,000 years ago, after the emergence of anatomically modern humans.

Pregnancy in women with perinatally acquired HIV-infection: outcomes and challenges.

This is a retrospective comparison of pregnant women with perinatally acquired HIV-infection (PAH) with a cohort of pregnant women with behaviorally acquired HIV-infection (BAH). PAH cases (11 women) included all pregnant adolescents followed at our HIV clinic from January 2000 to January 2009. BAH cases (27 women) were randomly selected from all deliveries within the study period at the same institution. Demographics, mode of delivery, CD4+ counts, and viral loads (VLs) before, during, and six months postpartum, as well as neonatal outcomes, were reviewed. CD4 counts were significantly lower in the PAH group. VLs were statistically higher in the PAH group. VLs were undetectable at delivery in 60% of the PAH group compared with 88% of the BAH group. No cases of vertical transmission occurred. PAH women may be at a higher risk for HIV-related disease progression. This may increase vertical transmission risks. Further studies and interventions with this growing population are warranted.

Decay kinetics of HIV-1 specific T cell responses in vertically HIV-1 exposed seronegative infants.

OBJECTIVE: The majority of infants born, in developed countries, to HIV-1 positive women are exposed to the HIV-1 virus in utero or peri/post-partum, but are born uninfected. We, and others, have previously shown HIV-1 specific T cell responses in HIV-1 exposed seronegative (HESN) neonates/infants. Our objective in this study was to examine the rate of decay in their HIV-1 specific T cell response over time from birth. DESIGN: Cross-sectional and longitudinal studies of HIV-1 specific T cell responses in HESN infants were performed. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated from 18 HIV-1 DNA PCR negative infants born to HIV-1 infected mothers receiving care at the Jacobi Medical Center, Bronx, NY, USA. PBMC were examined for T cell responses to HIV-1 antigens by interferon-gamma (IFN-γ) ELISPOT. RESULTS: PBMC from 15 HESN neonates/infants were analyzed. We observed a decay of HIV-1 specific T cell responses from birth at a rate of -0.599 spot forming unit/106 cells per day, with a median half-life decay rate of 21.38 weeks (13.39-115.8). CONCLUSION: Our results support the dynamic nature of T cell immunity in the context of a developing immune system. The disparate rate of decay with studies of adults placed on antiretroviral drugs suggests that antigen specific T cell responses are driven by the natural rate of decay of the T cell sub-populations themselves.

Profile of darunavir in the treatment of HIV-infected pediatric and adolescent patients.

The introduction of protease inhibitors (PI) containing antiretroviral regimens in the treatment of HIV infection in infants, children, and adolescents has dramatically decreased morbidity and mortality. Darunavir, the latest PI to be FDA approved for pediatric patients older than 6 years and currently the preferred PI for use in adult patients, was added as an alternative PI for use in children based on a combination of data from both adult and pediatric trials. This review of darunavir in the treatment of HIV-infected children and adolescents looks at the major published clinical trials findings, pharmacokinetic and resistance studies, and preliminary data on use in younger children.

Cross-sectional dating of novel haplotypes of HERV-K 113 and HERV-K 115 indicate these proviruses originated in Africa before Homo sapiens.

The human genome, human endogenous retroviruses (HERV), of which HERV-K113 and HERV-K115 are the only known full-length proviruses that are insertionally polymorphic. Although a handful of previously published papers have documented their prevalence in the global population; to date, there has been no report on their prevalence in the United States population. Here, we studied the geographic distribution of K113 and K115 among 156 HIV-1+ subjects from the United States, including African Americans, Hispanics, and Caucasians. In the individuals studied, we found higher insertion frequencies of K113 (21%) and K115 (35%) in African Americans compared with Caucasians (K113 9% and K115 6%) within the United States. We also report the presence of three single nucleotide polymorphism sites in the K113 5' long terminal repeats (LTRs) and four in the K115 5' LTR that together constituted four haplotypes for K113 and five haplotypes for K115. HERV insertion times can be estimated from the sequence differences between the 5' and 3' LTR of each insertion, but this dating method cannot be used with HERV-K115. We developed a method to estimate insertion times by applying coalescent inference to 5' LTR sequences within our study population and validated this approach using an independent estimate derived from the genetic distance between K113 5' and 3' LTR sequences. Using our method, we estimated the insertion dates of K113 and K115 to be a minimum of 800,000 and 1.1 million years ago, respectively. Both these insertion dates predate the emergence of anatomically modern Homo sapiens.

Lower cytokine secretion ex vivo by natural killer T cells in HIV-infected individuals is associated with higher CD161 expression.

OBJECTIVE: Natural killer T (NKT) cells are efficiently targeted by HIV and severely reduced in numbers in the circulation of infected individuals. The functional capacity of the remaining NKT cells in HIV-infected individuals is poorly characterized. This study measured NKT cell cytokine production directly ex vivo and compared these responses with both the disease status and NKT subset distribution of individual patients. METHODS: NKT cell frequencies, subsets, and ex-vivo effector functions were measured in the peripheral blood mononuclear cells of HIV-infected patients and healthy controls by flow cytometry. We measured cytokines from NKT cells after stimulation with either alpha-galactosyl ceramide-loaded CD1d dimers (DimerX-alphaGalCer) or phorbol myristate acetate and ionomycin. RESULTS: The frequencies of NKT cells secreting interferon-gamma and tumor necrosis factor-alpha were significantly lower in HIV-infected patients than healthy controls after DimerX-alphaGalCer treatment, but responses were similar after treatment with phorbol myristate acetate and ionomycin. The magnitude of the interferon-gamma response to DimerX-alphaGalCer correlated inversely with the number of years of infection. Both interferon-gamma and tumor necrosis factor-alpha production in response to DimerX-alphaGalCer correlated inversely with CD161 expression. CONCLUSION: The ex-vivo Th1 responses of circulating NKT cells to CD1d-glycolipid complexes are impaired in HIV-infected patients. NKT cell functions may be progressively lost over time in HIV infection, and CD161 is implicated in the regulation of NKT cell responsiveness.