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BackgroundThis study estimated the number of daily tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) doses required to achieve and maintain (after discontinuation) intracellular drug concentrations that protect against human immunodeficiency virus (HIV) infection for men who have sex with men (MSM).MethodsTenofovir diphosphate (TFV-DP) concentrations in peripheral blood mononuclear cells (PBMCs) and rectal mononuclear cells from an intensive pharmacokinetic study ("Cell-PrEP" [preexposure prophylaxis]) of 30 days of daily TDF/FTC followed by 30 days off drug were evaluated. A regression formula for HIV risk reduction derived from PBMCs collected in the preexposure prophylaxis initiative study was used to calculate inferred risk reduction. The time required to reach steady state for TFV-DP in rectal mononuclear cells was also determined.ResultsTwenty-one HIV-uninfected adults participated in Cell-PrEP. The inferred HIV risk reduction, based on PBMC TFV-DP concentration, reached 99% (95% confidence interval [CI], 69%-100%) after 5 daily doses, and remained >90% for 7 days after stopping drug from steady-state conditions. The proportion of participants reaching the 90% effective concentration (EC90) was 77% after 5 doses and 89% after 7 doses. The percentage of steady state for natural log [TFV-DP] in rectal mononuclear cells was 88% (95% CI, 66%-94%) after 5 doses and 94% (95% CI, 78%-98%) after 7 doses.ConclusionsHigh PrEP activity for MSM was achieved by approximately 1 week of daily dosing. Although effective intracellular drug concentrations persist for several days after stopping PrEP, a reasonable recommendation is to continue PrEP dosing for 4 weeks after the last potential HIV exposure, similar to recommendations for postexposure prophylaxis.

The majority of HIV-infected individuals fail to produce protective antibodies and have diminished responses to new immunizations (1-3). We report here that even though there is an expansion of follicular helper T ([T.sub.FH]) cells in HIV-infected individuals, the cells are unable to provide adequate B cell help. We found a higher frequency of programmed cell death ligand 1 ([PD-L1).sup.+] germinal center B cells from lymph nodes of HIV-infected individuals suggesting a potential role for PD-1-PD-L1 interaction in regulating [T.sub.FH] cell function. In fact, we show that engagement of PD-1 on [T.sub.FH] cells leads to a reduction in cell proliferation, activation, inducible T-cell co-stimulator (ICOS) expression and interleukin-21 (IL-21) cytokine secretion. Blocking PD-1 signaling enhances HIV-specific immunoglobulin production in vitro. We further show that at least part of this defect involves IL-21, as addition of this cytokine rescues antibody responses and plasma cell generation in vitro. Our results suggest that deregulation of [T.sub.FH] cell-mediated B cell help diminishes B cell responses during HIV infection and may be related to PD-1 triggering on [T.sub.FH] cells. These results demonstrate a role for [T.sub.FH] cell impairment in HIV pathogenesis and suggest that enhancing their function could have a major impact on the outcome and control of HIV infection, preventing future infections and improving immune responses to vaccinations., During HIV infection there is a profound deregulation in B cell function (4-6). However, little is known about the underlying mechanisms that alter B cell responses and antibody production at [...]

The determination of whether [alpha]-defensins are present in HIV-1-infected individuals' lymphoid tissue, the major site of HIV-1 replication, and the identification of cells that express them are reported. The results have shown that [alpha]-defensins within lymphoid tissue are expressed by granulocytes and are prevalent in HIV-1-seronegative individuals with inflammatory processes as well as HIV-1-infected individuals.

A study report provides the first systematic description of the characteristics of AIDS-related Kaposi sarcoma (AIDS-KS) in African women and the first comparison of the viral and immunologic markers of HIV-1 and KS disease in women and men. The findings reveal that women are more likely to have symptoms of fever, diaphoresis, or weight loss suggests underlying differences in the biology and pathogenesis of KS disease and/or HIV-1 disease in women compared with men or gender differences in the incidence of other coinfections.

Human and simian immunodeficiency viruses (HIV and SIV) exploit follicular lymphoid regions by establishing high levels of viral replication and dysregulating humoral immunity. Follicular regulatory T cells (TFR) are a recently characterized subset of lymphocytes that influence the germinal centre response through interactions with follicular helper T cells (TFH). Here, utilizing both human and rhesus macaque models, we show the impact of HIV and SIV infection on TFR number and function. We find that TFR proportionately and numerically expand during infection through mechanisms involving viral entry and replication, TGF-β signalling, low apoptosis rates and the presence of regulatory dendritic cells. Further, TFR exhibit elevated regulatory phenotypes and impair TFH functions during HIV infection. Thus, TFR contribute to inefficient germinal centre responses and inhibit HIV and SIV clearance. [ABSTRACT FROM AUTHOR]

Reduced frequencies of myeloid and plasmacytoid dendritic cell (DC) subsets (mDCs and pDCs, respectively) have been observed in the peripheral blood of HIV-1-infected individuals throughout the course of disease. Accumulation of DCs in lymph nodes (LNs) may partly account for the decreased numbers observed in blood, but increased DC death may also be a contributing factor. We used multiparameter flow cytometry to evaluate pro- and antiapoptotic markers in blood mDCs and pDCs from untreated HIV-1-infected donors, from a subset of infected donors before and after receiving antiretroviral therapy (ART), and from uninfected control donors. Blood mDCs, but not pDCs, from untreated HIV-1-infected donors expressed lower levels of antiapoptotic Bcl-2 than DCs from uninfected donors. A subset of HIV-1-infected donors had elevated frequencies of proapoptotic caspase-3+ blood mDCs, and positive correlations were observed between caspase-3+ mDC frequencies and plasma viral load and CD8+ T-cell activation levels. Caspase-3+ mDC frequencies, but not mDC Bcl-2 expression, were reduced with viral suppression on ART. Apoptosis markers on DCs in blood and LN samples from a cohort of untreated, HIV-1-infected donors with chronic disease were also evaluated. LN mDCs displayed higher levels of Bcl-2 and lower caspase-3+ frequencies than did matched blood mDCs. Conversely, LN pDCs expressed lower Bcl-2 levels than their blood counterparts. In summary, blood mDCs from untreated HIV-1-infected subjects displayed a proapoptotic profile that was partially reversed with viral suppression, suggesting that DC death may be a factor contributing to blood DC depletion in the setting of chronic, untreated HIV disease. [ABSTRACT FROM AUTHOR]

Background: Elevated immune activation is associated with an increased risk of HIV acquisition. Tenofovir (TFV) has immunomodulatory properties in vitro, but how this extends in vivo remains unknown., Methods: HIV-negative adults received daily coformulated TFV disoproxil fumarate 300 mg/emtricitabine (FTC) 200 mg for 30 days followed by a 30-day washout. Markers of T-cell activation, inflammation, and cytokines were measured before drug and on days 30 (on drug) and 60 (30-day washout). Data were analyzed using one-way analysis of variance/pairwise comparisons. Intracellular disposition of TFV-diphosphate and FTC-triphosphate in CD4 and CD8 T-cells and monocytes was characterized, and the relationship with immune activation was evaluated using Pearson's correlation coefficient., Results: T-cell activation was available in 19 participants. CD38/HLA-DR coexpression on CD8 T-cells decreased from baseline to day 30 (3.97% vs. 2.71%; P = 0.03) and day 60 (3.97% vs. 2.41%; P = 0.008). Soluble CD27 decreased from baseline to day 60 (184.1 vs. 168.4 pg/mL; P = 0.001). Cytokines and inflammation markers were not significantly different. TFV-diphosphate and FTC-triphosphate were approximately 4-fold higher in monocytes vs. CD4 and CD8 T-cells but neither correlated with activation markers., Conclusions: TFV disoproxil fumarate/FTC therapy was associated with decreased T-cell activation in HIV-negative adults, which could contribute to the antiviral effect of pre-exposure prophylaxis (NCT01040091; www.clinicaltrials.gov).

The mechanisms mediating arterial stiffening with aging and menopause are not completely understood. We determined whether administration of tetrahydrobiopterin (BH(4)), a critical cofactor for endothelial nitric oxide synthase to produce nitric oxide, would increase vascular endothelial-dependent vasodilatory tone and decrease arterial stiffness in estrogen-deficient postmenopausal women. Additionally, we examined whether the beneficial effects of estrogen on vascular function were possibly related to BH(4). Arterial stiffness (carotid artery compliance) and endothelial-dependent vasodilation [brachial artery flow-mediated dilation (FMD)] were measured in postmenopausal (n = 24; 57 ± 1 yr, mean ± SE) and eumenorrheic premenopausal (n = 9; 33 ± 2 yr) women before and 3 h after the oral administration of BH(4). Subsequently, in postmenopausal women, vascular testing (before and after BH(4)) was repeated following randomization to either 2 days of transdermal estradiol or placebo. Baseline carotid artery compliance and brachial artery FMD were lower in postmenopausal than in premenopausal women (P < 0.0001). BH(4) administration increased carotid artery compliance (0.61 ± 0.05 to 0.73 ± 0.04 mm(2)·mmHg(-1)·10(-1) vs. baseline, P < 0.0001) and brachial artery FMD (P < 0.001) in postmenopausal women but had no effect in premenopausal women (P = 0.62). Carotid artery compliance (0.59 ± 0.05 to 0.78 ± 0.06 mm(2)·mmHg(-1)·10(-1), P < 0.001) and FMD increased in postmenopausal women in response to estradiol (P = 0.02) but were not further improved with the coadministration of BH(4), possibly because estrogen increased BH(4) bioavailability. Carotid artery compliance and FMD increased with BH(4) in the placebo group (P = 0.02). Although speculative, these results suggest that reduced vascular BH(4) may be an important contributor to arterial stiffening in estrogen-deficient postmenopausal women, related in part to reduced endothelial-dependent vasodilatory tone.

Background: New HIV-1 infections are increasing in older American women largely through heterosexual transmission. Activated CD4+ T cells and CCR5 expression are linked to HIV-1 susceptibility, but whether these parameters are altered in the cervix of older women is unknown., Methods: Whole blood and in some instances endocervical brush samples were collected from healthy premenopausal (n = 22) and postmenopausal women (n = 24). Percentages of HLA-DR(DR)+CD38(38)+CD4+ T cells and HIV-1 chemokine coreceptor expression were determined by flow cytometry., Results: Percentages of DR+38+CD4+ T cells were 6 times greater in cervix (median: 6.4%) than blood (median: 1.1%; P < 0.001) but did not differ within each compartment between premenopausal and postmenopausal women (P = 0.2). Postmenopausal women had greater percentages of CCR5+CD4+ and CCR5+DR+38+CD4+ T cells compared with premenopausal women in cervix (median: 70% vs. 42%, P = 0.005; and 80% vs. 57%; P = 0.05, respectively) and blood (medians: 22% vs. 13%, and 76% vs. 62%, respectively; P < 0.001). Postmenopausal women had more CCR5 molecules on cervical DR+38+CD4+ T cells (median: 3176) than premenopausal women (median: 1776; P = 0.02). Age and percent CCR5+CD4+ and CCR5+DR+38+CD4+ cells were linearly related in cervix (r(2) = 0.47, P < 0.001 and r(2) = 0.25, P = 0.01, respectively) and blood (r(2) = 0.20, P = 0.001 and r(2) = 0.31, P < 0.001; respectively), but confounding of age with menopause could not be excluded. Cervical CXCR4 expression did not differ substantially between premenopausal and postmenopausal women., Conclusions: Elevated cervical CCR5 expression in postmenopausal women may increase their risk for HIV-1 acquisition. Studies are needed to confirm whether elevated CCR5 expression confers increased HIV-1 susceptibility in postmenopausal women, and if it is related to hormonal or nonhormonal effects of aging.

Percentages of activated T cells correlate with HIV-1 disease progression, but the underlying mechanisms are not fully understood. We hypothesized that HLA-DR(+) CD38(+) (DR(+) 38(+)) CD4(+) T cells produce the majority of HIV-1 due to elevated expression of CCR5 and CXCR4. In phytohemagglutinin (PHA)-stimulated CD8-depleted peripheral blood mononuclear cells (PBMC) infected with HIV-1 green fluorescent protein (GFP) reporter viruses, DR(-) 38(+) T cells constituted the majority of CCR5 (R5)-tropic (median, 62%) and CXCR4 (X4)-tropic HIV-1-producing cells (median, 61%), although cell surface CCR5 and CXCR4 were not elevated in this subset of cells. In lymph nodes from untreated individuals infected with R5-tropic HIV-1, percentages of CCR5(+) cells were elevated in DR(+) 38(+) CD4(+) T cells (median, 36.4%) compared to other CD4(+) T-cell subsets (median values of 5.7% for DR(-) 38(-) cells, 19.4% for DR(+) 38(-) cells, and 7.6% for DR(-) 38(+) cells; n = 18; P < 0.001). In sorted CD8(-) lymph node T cells, median HIV-1 RNA copies/10(5) cells was higher for DR(+) 38(+) cells (1.8 × 10(6)) than for DR(-) 38(-) (0.007 × 10(6)), DR(-) 38(+) (0.064 × 10(6)), and DR(+) 38(-) (0.18 × 10(6)) subsets (n = 8; P < 0.001 for all). After adjusting for percentages of subsets, a median of 87% of viral RNA was harbored by DR(+) 38(+) cells. Percentages of CCR5(+) CD4(+) T cells and concentrations of CCR5 molecules among subsets predicted HIV-1 RNA levels among CD8(-) DR/38 subsets (P < 0.001 for both). Median HIV-1 DNA copies/10(5) cells was higher in DR(+) 38(+) cells (5,360) than in the DR(-) 38(-) (906), DR(-) 38(+) (814), and DR(+) 38(-) (1,984) subsets (n = 7; P ≤ 0.031). Thus, DR(+) 38(+) CD4(+) T cells in lymph nodes have elevated CCR5 expression, are highly susceptible to infection with R5-tropic virus, and produce the majority of R5-tropic HIV-1. PBMC assays failed to recapitulate in vivo findings, suggesting limited utility. Strategies to reduce numbers of DR(+) 38(+) CD4(+) T cells may substantially inhibit HIV-1 replication.

Reduced frequencies of myeloid and plasmacytoid dendritic cell (DC) subsets (mDCs and pDCs, respectively) have been observed in the peripheral blood of HIV-1-infected individuals throughout the course of disease. Accumulation of DCs in lymph nodes (LNs) may partly account for the decreased numbers observed in blood, but increased DC death may also be a contributing factor. We used multiparameter flow cytometry to evaluate pro- and antiapoptotic markers in blood mDCs and pDCs from untreated HIV-1-infected donors, from a subset of infected donors before and after receiving antiretroviral therapy (ART), and from uninfected control donors. Blood mDCs, but not pDCs, from untreated HIV-1-infected donors expressed lower levels of antiapoptotic Bcl-2 than DCs from uninfected donors. A subset of HIV-1-infected donors had elevated frequencies of proapoptotic caspase-3(+) blood mDCs, and positive correlations were observed between caspase-3(+) mDC frequencies and plasma viral load and CD8(+) T-cell activation levels. Caspase-3(+) mDC frequencies, but not mDC Bcl-2 expression, were reduced with viral suppression on ART. Apoptosis markers on DCs in blood and LN samples from a cohort of untreated, HIV-1-infected donors with chronic disease were also evaluated. LN mDCs displayed higher levels of Bcl-2 and lower caspase-3(+) frequencies than did matched blood mDCs. Conversely, LN pDCs expressed lower Bcl-2 levels than their blood counterparts. In summary, blood mDCs from untreated HIV-1-infected subjects displayed a proapoptotic profile that was partially reversed with viral suppression, suggesting that DC death may be a factor contributing to blood DC depletion in the setting of chronic, untreated HIV disease.

Dendritic cells (DCs) from HIV-1-infected individuals display numeric and functional defects, and recent evidence suggests that HIV-1 can directly and indirectly activate DCs in vitro. The in vivo activation state and compartmentalization of DC subsets during HIV-1 infection remain poorly understood, however. We evaluated phenotypic and functional characteristics of myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) directly ex vivo in peripheral blood and lymphoid tissue from HIV-1-infected and HIV-seronegative individuals. Analysis of a wide range of chemokine receptors and activation/maturation markers on circulating DCs from viremic HIV-1-infected donors revealed a phenotype indicative of partial activation. Yet, blood DCs from viremic subjects still achieved full maturation when stimulated in vitro. In addition, blood pDCs from viremic individuals had a reduced capacity to migrate to CXCL12 in vitro. Total numbers of both DC subsets were increased in lymph nodes of asymptomatic untreated HIV-1-infected subjects, consistent with DC accumulation in the lymphoid compartment. Lymph node DCs also expressed high levels of CD40 in the absence of increases of other typical activation/maturation markers. Activation and depletion of DCs in blood with accumulation in lymphoid tissue may contribute to HIV-associated chronic immune activation and T-cell dysfunction.

Functional impairment of HIV-specific CD4(+) T cells during chronic HIV infection is closely linked to viral replication and thought to be due to T cell exhaustion. Programmed death 1 (PD-1) has been linked to T cell dysfunction in chronic viral infections, and blockade of the PD-1 pathway restores HIV-specific CD4(+) and CD8(+) T cell function in HIV infection. This study extends those findings by directly examining PD-1 expression on virus-specific CD4(+) T cells. To investigate the role of PD-1 in HIV-associated CD4(+) T cell dysfunction, we measured PD-1 expression on blood and lymph node T cells from HIV-infected subjects with chronic disease. PD-1 expression was significantly higher on IFN-gamma-producing HIV-specific CD4(+) T cells compared with total or CMV-specific CD4(+) T cells in untreated HIV-infected subjects (p = 0.0001 and p < 0.0001, respectively). PD-1 expression on HIV-specific CD4(+) T cells from subjects receiving antiretroviral therapy was significantly reduced (p = 0.007), and there was a direct correlation between PD-1 expression on HIV-specific CD4(+) T cells and plasma viral load (r = 0.71; p = 0.005). PD-1 expression was significantly higher on HIV-specific T cells in the lymph node, the main site of HIV replication, compared with those in the blood (p = 0.0078). Thus, PD-1 expression on HIV-specific CD4(+) T cells is driven by persistent HIV replication, providing a potential target for enhancing the functional capacity of HIV-specific CD4(+) T cells.

alpha-Defensins 1, 2, and 3 exert antiretroviral activity in vitro, but their role in controlling HIV-1 replication in vivo and the cells that produce them are controversial. This study sought to determine whether alpha-defensins are present in HIV-1-infected individuals' lymphoid tissues, the major site of HIV-1 replication, and to identify the cells that express them. alpha-Defensin expression was evaluated by immunostaining inguinal lymph node sections from 19 untreated HIV-1-infected individuals and 8 individuals at low risk or seronegative for HIV-1 infection. Percentages of tissue sections that stained positively for alpha-defensins were not significantly different between HIV-seropositive (median, 7.6%) and -seronegative (median, 5.5%) individuals. Conditions that could have produced lymph node inflammation were present in most seronegative subjects, and their lymph node weights correlated with alpha-defensin expression (Spearman rho = 0.833; P = 0.010). A median of 100% (range, 95%-100%) of alpha-defensin-expressing lymph node cells from 8 subjects coexpressed the granulocyte marker, CD15. CD15 and alpha-defensin staining correlated (Spearman rho = 0.622; P < 0.001). These data suggest that alpha-defensins within lymphoid tissue are expressed by granulocytes and are prevalent in HIV-1-seronegative individuals with inflammatory processes as well as HIV-1-infected individuals. The role of alpha-defensins in controlling HIV-1 replication merits further investigation.