Distinct Inflammatory Phenotypes are associated with subclinical and clinical Cardiovascular disease in People living with HIV

Despite inflammation being implicated in cardiovascular disease (CVD) in people with HIV (PWH), considerable heterogeneity within populations of PWH exists. Stratifying CVD risk based on inflammatory phenotype could play an important role. Using principal component analyses and unsupervised hierarchical clustering, we examined 38 biomarkers to identify inflammatory phenotypes in two independent cohorts of PWH. We identified three distinct inflammatory clusters present in both cohorts that associated with altered risk of both subclinical CVD (cohort 1) and prevalent clinical CVD (cohort 2) after adjusting for CVD risk factors. These data support precision medicine approaches to enhance CVD risk assessment in PWH.

A comprehensive review of the nasal microbiome in chronic rhinosinusitis (CRS)

Chronic rhinosinusitis (CRS) has been known as a disease with strong infectious and inflammatory components for decades. The recent advancement in methods identifying microbes has helped implicate the airway microbiome in inflammatory respiratory diseases such as asthma and COPD. Such studies support a role of resident microbes in both health and disease of host tissue, especially in the case of inflammatory mucosal diseases. Identifying interactive events between microbes and elements of the immune system can help us to uncover the pathogenic mechanisms underlying CRS. Here we provide a review of the findings on the complex upper respiratory microbiome in CRS in comparison with healthy controls. Furthermore, we have reviewed the defects and alterations of the host immune system that interact with microbes and could be associated with dysbiosis in CRS.

Gut dendritic cell activation links an altered colonic microbiome to mucosal and systemic T-cell activation in untreated HIV-1 infection

HIV-1-associated disruption of intestinal homeostasis is a major factor contributing to chronic immune activation and inflammation. Dendritic cells (DCs) are crucial in maintaining intestinal homeostasis, but the impact of HIV-1 infection on intestinal DC number and function has not been extensively studied. We compared the frequency and activation/maturation status of colonic myeloid DC (mDC) subsets (CD1c(+) and CD1c(neg)) and plasmacytoid DCs in untreated HIV-1-infected subjects with uninfected controls. Colonic mDCs in HIV-1-infected subjects had increased CD40 but decreased CD83 expression, and CD40 expression on CD1c(+) mDCs positively correlated with mucosal HIV-1 viral load, with mucosal and systemic cytokine production, and with frequencies of activated colon and blood T cells. Percentage of CD83(+)CD1c(+) mDCs negatively correlated with frequencies of interferon-γ-producing colon CD4(+) and CD8(+) T cells. CD40 expression on CD1c(+) mDCs positively associated with abundance of high prevalence mucosal Prevotella copri and Prevotella stercorea but negatively associated with a number of low prevalence mucosal species, including Rumminococcus bromii. CD1c(+) mDC cytokine production was greater in response to in vitro stimulation with Prevotella species relative to R. bromii. These findings suggest that, during HIV infection, colonic mDCs become activated upon exposure to mucosal pathobiont bacteria leading to mucosal and systemic immune activation.

An altered intestinal mucosal microbiome in HIV-1 infection is associated with mucosal and systemic immune activation and endotoxemia

Human immunodeficiency virus-1 (HIV-1) infection disrupts the intestinal immune system, leading to microbial translocation and systemic immune activation. We investigated the impact of HIV-1 infection on the intestinal microbiome and its association with mucosal T-cell and dendritic cell (DC) frequency and activation, as well as with levels of systemic T-cell activation, inflammation, and microbial translocation. Bacterial 16S ribosomal DNA sequencing was performed on colon biopsies and fecal samples from subjects with chronic, untreated HIV-1 infection and uninfected control subjects. Colon biopsies of HIV-1-infected subjects had increased abundances of Proteobacteria and decreased abundances of Firmicutes compared with uninfected donors. Furthermore at the genus level, a significant increase in Prevotella and decrease in Bacteroides was observed in HIV-1-infected subjects, indicating a disruption in the Bacteroidetes bacterial community structure. This HIV-1-associated increase in Prevotella abundance was associated with increased numbers of activated colonic T cells and myeloid DCs. Principal coordinates analysis demonstrated an HIV-1-related change in the microbiome that was associated with increased mucosal cellular immune activation, microbial translocation, and blood T-cell activation. These observations suggest that an important relationship exists between altered mucosal bacterial communities and intestinal inflammation during chronic HIV-1 infection.

Evaluation of the impact of highly active antiretroviral therapy on immune recovery in antiretroviral naive patients

OBJECTIVES

To examine the extent of immune reconstitution in treatment-naive patients with CD4 T-cell counts <500 cells/microL following 48 weeks of highly active antiretroviral therapy (HAART).

METHODS

Thirteen antiretroviral naive patients were evaluated longitudinally for 48 weeks on HAART utilizing immune functional and lymphocyte phenotyping assays, including lymphocyte proliferation assay, flow cytometric evaluation of cell surface markers, and delayed type hypersensitivity skin tests. Virologic responses were monitored using commercially available viral load assays and gag/pol mRNA quantification using simultaneous immunophenotyping/UltraSensitive fluorescence in situ hybridization (ViroTect In Cell HIV-1 Detection Kit; Invirion, Frankfort, MI). Thymic function was evaluated for a subset of four patients using real-time polymerase chain reaction (PCR) for T-cell receptor excision circle (TREC) quantification and thymic scans using computerized axial tomography (CT) of the thymus.

RESULTS

HAART initiation resulted in a significant decline in plasma viremia and percentage of infected peripheral blood cells, and a rise in CD4 T cells from a baseline median of 207 cells/microL to a week-48 median of 617 cells/microL. The rise was predominately in CD4 memory cells. Naive T cells also increased in number, but at a slower rate. Activated (HLA-DR CD38) CD4 and CD8 T cells were elevated at baseline (24 and 62%, respectively) and declined by week 48 (17 and 36%, respectively) but did not reach normal levels. The number of Fas CD4 T cells increased from a baseline median of 169 to 381 cells/microL at week 48. Both soluble interleukin (IL)-2 and tumour necrosis factor (TNF) II receptors declined by week 48. HIV p24 lymphocyte proliferation assay responses were transiently detected in three patients. TREC values increased from a median 6400 copies/microg at baseline to a week-48 median value of 26 697 copies/microg.

CONCLUSION

Immune functional reconstitution was not achieved in these HAART naive patients.

Determinants of HIV-1 shedding in the genital tract of women

BACKGROUND

Plasma HIV-1 RNA concentration has been the best predictor for risk of heterosexual and perinatal transmission. However, direct contact with HIV-1 present locally in the genital tract might be necessary for transmission. We aimed to assess the relation between HIV-1 shedding (RNA or culturable virus) in female genital secretions and other factors that might affect HIV-1 shedding.

METHODS

This was a cross-sectional study within the Women's Interagency HIV Study (WIHS), a prospective longitudinal cohort study of HIV-infected women. We enrolled 311 HIV positive women from Jan 30, 1997 to July 1, 1998. We did clinical assessments, cultured HIV-1, and measured RNA in peripheral blood mononuclear cells (PBMC) and genital secretions. We compared the results with univariate and multivariate analyses. Presence of HIV-1 RNA or culturable virus in genital secretions was defined as HIV-1 shedding.

FINDINGS

HIV-1 RNA was present in genital secretions of 57% (152/268) of women whereas infectious virus was detected only in 6% (17/271). Genital tract HIV-1 shedding was found in 80% (130/163) of women with detectable plasma RNA and 78% (116/148) of women with positive PBMC cultures. 33% (27/83) of women with less than 500 copies/mL plasma RNA and 39% (35/90) of those with negative PBMC cultures also had genital tract shedding.

INTERPRETATION

Plasma RNA concentration, both qualitatively and quantitatively, was the most important factor in predicting genital HIV-1 shedding, even among women receiving potent antiretroviral therapy. However, HIV-1 shedding did occur in women with less than 500 copies/mL plasma HIV-1 RNA. This finding suggests that a separate reservoir of HIV-1 replication may exist in some women.

Variation of human immunodeficiency virus type 1 viral RNA levels in the female genital tract: implications for applying measurements to individual women

The short-term detection and variability of human immunodeficiency virus type 1 (HIV-1) RNA level was assessed in the blood plasma and genital tracts of 55 HIV-1-infected women. Specimens were collected weekly for 8 weeks from the endocervical canal with wicks and cytobrushes and from the ectocervix and vagina with cervicovaginal lavage. In all, 48 women (87.3%) had detectable genital tract HIV-1 RNA at > or =1 collection times. HIV-1 RNA levels varied least in specimens from endocervical canal wick and most in cervicovaginal lavage samples. The within-subject variation for genital-tract virus level was greater than that for blood. Overall, the odds for viral RNA detection in the genital tract approximately tripled for each 10-fold increase in plasma viral RNA concentration (P<.001) or with concomitant genital tract infection (P=.003). Endocervical canal wicks should be considered as an adjunct to cervicovaginal lavage, to improve the sensitivity and precision of HIV-1 RNA detection.

T cell receptor excision circle (TREC) content following maximum HIV suppression is equivalent in HIV-infected and HIV-uninfected individuals

BACKGROUND

The adult human thymus contributes to de novo T cell synthesis; such synthesis can be assessed by analyzing T cell receptor excision circles (TREC).

METHODS

TREC levels were measured in total peripheral blood mononuclear cells (PBMC) and CD4- and CD8-enriched cells of 29 HIV-positive patients with maximal viral suppression. The expression of CD45RA+CD45RO-, CD45RA+CD62L+, CD45RO-CD27+CD95low and HLA-DR+CD38+ was assessed using three-color flow cytometric analysis of whole blood. Thymic index score was based on computed tomographic scans of the thymus. The relationship of TREC with thymic index and the expression of the naive phenotypes was evaluated.

RESULTS

TREC expression was not statistically different in these HIV-positive patients from that in age-matched HIV-negative controls. Among HIV-positive patients with CD4 cell count of > 500 x 10(6) cells/l after antiretroviral therapy (n = 15), PBMC TREC levels correlated with the expression of CD45RA+CD45RO- and CD45RA+CD62L+ naive phenotypes, and inversely correlated with the expression of HLA-DR+CD38+. The change between pre- and post-therapy CD4 cell counts for these 15 patients significantly correlated with both thymic index and expression of the CD45RA+CD45RO- phenotype.

CONCLUSIONS

The finding that TREC expression was equivalent between HIV-positive patients after therapy and HIV-negative donors suggests that there is no reduction in thymic output among HIV-positive individuals after therapy. Given that TREC is inversely correlated with HLA-DR/CD38 expression, its analysis in studies of thymopoiesis should be evaluated in the context of maximum viral suppression to reduce HIV-mediated immune activation and/or by normalizing for cell turnover.

Persistence of intracellular HIV-1 mRNA correlates with HIV-1-specific immune responses in infected subjects on stable HAART

OBJECTIVE

To determine if low level, persistent, HIV-1 replication within specific immune cells contributes to HIV-1-specific immune responsiveness.

DESIGN

We analyzed 59 HIV-1-infected subjects on stable highly active antiretroviral therapy (HAART) therapy (not including zidovudine) with suppressed plasma viremia (< 400 copies/ml) for phenotypic and lymphoproliferative correlates of immune function.

METHODS

Peripheral blood mononuclear cells were collected for immunophenotyping, lymphoproliferative assays, and simultaneous immunophenotyping/ultrasensitive in situ hybridization. Plasma was collected for plasma viral load as determined by the Ultra Sensitive Roche Amplicor RT-PCR. Descriptive statistics (mean and SD, median, first and third quartiles) were determined for all variables in two groups defined as having persistent viral replication present or absent. The two-sided Wilcoxon test (continuity correction, 0.5) was used to compare lymphocyte phenotypes, lymphoproliferative assay responses, intracellular gag-pol mRNA, lowest CD4 counts and CD4% of these two groups.

RESULTS

HIV-1 replication in CD4, CD45RO memory T lymphocytes persists in spite of undetectable plasma viral load. Patients (n = 24) with persistent intracellular expression of HIV-1 mRNA (> 0.3%) showed significant in vitro proliferative responses to HIV-1 p24 (stimulation index > or = 10) compared to patients (n = 35) without persistent intracellular replication. The group with persistent HIV-1 replication in cells showed no significant response to the recall antigen tetanus toxoid but a trend toward higher responses to pathogen antigens. There were no differences between the groups in the prevalence of AIDS or occurrences of opportunistic infections; however, the high viral persistence group was more HAART experienced (P < 0.05).

CONCLUSIONS

These results suggest that HIV-1-specific immune responses correlate with evidence of ongoing HIV-1 replication.

Multiple CD4+ cell kinetic patterns and their relationships with baseline factors and virological responses in HIV type 1 patients receiving highly active antiretroviral therapy

This exploratory analyses characterizes patterns of lymphocyte recovery in HIV-1-infected patients treated with highly active antiretroviral therapy (HAART) and investigates their relationship with baseline indices and virologic responses. We modeled kinetics of total CD4+ lymphocytes, as well as naive (CD45RA+ CD62L+), and memory (CD45RA- CD45RO+) subsets in 48 patients treated with AZT/3TC/Ritonavir for 48 weeks in ACTG protocol 315. Cell kinetic indices were estimated by nonlinear regression methods and were correlated with baseline factors and virologic responses. Five different kinetic patterns were identified, including biphasic growth, growth-plateau, growth-depletion, decay-recovery, and biphasic decay. Although overall mean lymphocyte responses showed a biphasic increase in cell number, a careful investigation reveals that only one-third of patients actually followed the biphasic growth pattern in CD4+ cell response, while 44% of 48 patients from this study followed the growth-depletion pattern. CD4+ cell recovery during the first phase and the 48-week study period were negatively correlated with baseline CD4+ cell counts, and positively correlated with baseline viral load. Memory CD4+ cell recovery during the first phase was also negatively correlated with baseline memory CD4+ and total CD4+ cell number, but the recovery rate of memory CD4+ cells during the second phase was positively correlated with baseline CD4+ cell number. Patients with a decay in CD4+ cell count during treatment were more likely to have experienced virological rebound (58%) than patients with nondecay patterns (24%). The rate and magnitude of the absolute increase in total CD4+ and memory CD4+ cell number (but not naive CD4+ cells) during the second phase were lower in patients with viral rebound compared with patients with persistent viral suppression. These results show that the kinetics of lymphocyte reconstitution in response to potent antiretroviral therapy in individual patients vary considerably from the "classic" biphasic increase that characterizes the mean or median response pattern. Pattern analysis of lymphocyte kinetics may be useful for testing relationships among factors that modulate the response to treatment.

A menstrual cycle pattern for cytokine levels exists in HIV-positive women: implication for HIV vaginal and plasma shedding

OBJECTIVES

To evaluate the effect of the menstrual cycle in HIV-positive women on plasma and genital cytokine levels, interrelationships between vaginal and plasma cytokines, CD4 and CD8 T cell fluctuations, and genital and plasma viral loads.

METHODS

Plasma and cervicovaginal lavage specimens were collected from 55 HIV-positive women with CD4 cell counts < 350 cells/microl during phases of the menstrual cycle. Samples were assayed for IL-1beta, IL-6, IL-4, IL-8, IL-10, TGFbeta, TNFalpha, INFgamma, MIP1alpha, MIP1beta, RANTES, and TNFR-II using enzyme-linked immunosorbent assays. CD4 and CD8 T cell expression was evaluated by flow cytometry. Repeated measures regression models were used to assess the effect of the menstrual cycle on cytokines and viral load. Multivariate repeated regression models were used to assess the correlation among selected cytokines and between selected cytokines and HIV viral load.

RESULTS

Vaginal IL-1beta, IL-4, IL-6, IL-8, IL-10, MIP1beta, RANTES, TGFbeta, and TNFR-II were significantly elevated during menses but were not altered during other phases. Plasma cytokine levels were not altered during the menstrual cycle. A positive Candida culture increased vaginal IL-8 during menses, whereas vaginal discharge was associated with a reduction in vaginal IL-4, IL-10, and RANTES. CD4 and CD8 cell numbers did not vary with the menstrual cycle. Vaginal cytokine levels correlated only with vaginal viral load, in a sampling method-dependent manner.

CONCLUSION

We provide evidence of elevated vaginal cytokine levels during menses, which appear to regulate vaginal and not plasma HIV shedding, suggesting that a menstrual cycle pattern exists for cytokine production in HIV-positive women impacting vaginal shedding of HIV.

Upregulation of CD4 on CD8+ T cells: CD4dimCD8bright T cells constitute an activated phenotype of CD8+ T cells

Aside from an intermediate stage in thymic T-cell development, the expression of CD4 and CD8 is generally thought to be mutually exclusive, associated with helper or cytotoxic T-cell functions, respectively. Stimulation of CD8+ T cells, however, induces the de novo expression of CD4. We demonstrate that while superantigen (staphylococcal enterotoxin B, SEB) and anti-CD3/CD28 costimulation of purified CD8+ T cells induced the expression of CD4 on CD8+ T cells by 30 and 17%, respectively, phytohaemagglutinin (PHA) stimulation did not induce CD4 expression on purified CD8+ T cells but significantly induced the expression of both CD4 on CD8 (CD4dimCD8bright) and CD8 on CD4 (CD4brightCD8dim) T cells in unfractionated peripheral blood mononuclear cells (PBMC). The level of the PHA-mediated induction of CD4dimCD8bright and CD4brightCD8dim was at 27 and 17%, respectively. Depletion of CD4+ T cells from PBMC abrogated this PHA-mediated effect. Autologous CD4+ and CD8+ T-cell co-cultures in the presence of PHA induced this CD4dimCD8bright T-cell expression by 33%, demonstrating a role for CD4 cells in the PHA-mediated induction of the double positive cells. The induction of CD4dimCD8bright was independent of a soluble factor(s). Phenotypic analysis of CD4dimCD8bright T cells indicated significantly higher levels of CD95, CD25, CD38, CD69, CD28, and CD45RO expression than their CD8+CD4- counterparts. CD4dimCD8bright T cells were also negative for CD1a expression and were predominantly T-cell receptor (TCR) alphabeta cells. Our data demonstrate that CD4dimCD8bright T cells are an activated phenotype of CD8+ T cells and suggest that CD4 upregulation on CD8+ T cells may function as an additional marker to identify activated CD8+ T cells.

A potential role for interleukin-7 in T-cell homeostasis

Interleukin (IL)-7 is known to up-regulate thymopoietic pathways of T-cell regeneration. Recent work also has shown it to potently enhance thymic-independent peripheral expansion and to restore immunocompetence in athymic T-cell-depleted hosts. We hypothesized that endogenous IL-7 could contribute to the restoration of T-cell homeostasis following T-cell depletion. To analyze this, we evaluated circulating IL-7 levels and lymphocyte subsets in multiple clinical cohorts with T-cell depletion of varying etiologies. In pediatric (n = 41) and adult (n = 51) human immunodeficiency virus-infected CD4-depleted patients, there were strong inverse correlations between IL-7 levels and CD4 counts (r = -0.77, P <.0001, and r = -0.68, P <.0001). Declines in IL-7 were temporally correlated with recovery of CD4 counts. Similar patterns were observed in CD4-depleted patients receiving cancer chemotherapy (r = -0.65, P =.009). Therefore, in 2 disparate clinical scenarios involving CD4 depletion, IL-7 levels dynamically respond to changes in CD4 T-cell number, making this cytokine uniquely suited as a candidate regulator of T-cell homeostasis. Furthermore, in patients with idiopathic CD4 lymphopenia, a much weaker relationship between IL-7 levels and peripheral blood CD4 counts was observed, suggesting that an impaired IL-7 response to CD4 depletion may contribute to the impaired lymphocyte homeostasis observed in this population. In light of the known effects of IL-7 on T-cell regeneration, we postulate that increased availability of IL-7 could play a critical role in restoring T-cell homeostasis following T-cell depletion.

Quantitative single cell methods that identify cytokine and chemokine expression in dendritic cells

Two techniques based upon flow cytometry (FCM) and in situ image analysis were developed for quantification of intracellular cytokine and chemokine protein expression at the single cell level in dendritic cells (DCs). The qualitative and quantitative differences between the two methods were evaluated. In vitro differentiated DCs were stimulated with lipopolysaccaride (LPS) and thereafter stained for either IL-8, which is secreted through the Golgi-organelle, or IL-1ra, which localises diffusely in the cytoplasm. Microscopic examination, both for fluorophore and enzymatically stained cells, showed that DCs expressed IL-8 and IL-1ra with two different staining patterns. FCM analysis showed high frequencies of IL-1ra producing cells (76+/-13%), which was similar to the frequency obtained by in situ imaging. However, in contrast to IL-1ra, the incidence of IL-8 expressing DCs showed high variability between the donors. The numbers of positive cells were 19+/-19% as measured by FCM. The detection of IL-8 analysed by in situ imaging revealed higher frequencies (26+/-14%). The addition of brefeldin-A, leading to cytoplasmic accumulation of proteins secreted through the Golgi endoplasmatic route, generated a significantly increased signal intensity and incidence of producer cells, resulting in similar frequencies for both methods. FCM has the advantage of being less time consuming than image analysis and is also able to facilitate multiple colour analysis. However, FCM is less accurate in detecting and quantifying cytokines and chemokines with a preserved juxtanuclear staining pattern. The correct choice of detection technique therefore depends on the study question.

Anti-CCR5 antibodies in sera of HIV-positive individuals

One of the proposed mechanisms for resistance to human immunodeficiency virus-1 (HIV-1) infection is the presence of antibodies against receptor for CC-chemokines (CCR5). These antibodies, detected in sera of uninfected individuals exposed to HIV, have been shown to downmodulate surface CCR5 in vivo and are able to neutralize the infectivity of CCR5 strains in vitro. To address the potential role of anti-CCR5 antibodies in HIV infection, we analyzed anti-CCR5 antibody levels in plasma from HIV-infected patients who present a wide range of CD4(+) T-cell counts and viral load. Increased levels of anti-CCR5 antibodies were found in plasma from 13/46 HIV-positive donors compared with healthy controls (0/36). However, antibody levels were not associated with disease stage evaluated by CD4(+) T-cell counts and viral load.

Leukemia inhibitory factor inhibits HIV-1 replication and is upregulated in placentae from nontransmitting women

The placenta may play a critical role in inhibiting vertical transmission of HIV-1. Here we demonstrate that leukemia inhibitory factor (LIF) is a potent endogenous HIV-1-suppressive factor produced locally in placentae. In vitro, LIF exerted a potent, gp130-LIFRbeta-dependent, HIV coreceptor-independent inhibition of HIV-1 replication with IC50 values between 0.1 pg/ml and 0.7 pg/ml, depending on the HIV-1 isolate. LIF also inhibited HIV-1 in placenta and thymus tissues grown in ex vivo organ culture. The level of LIF mRNA and the incidence of LIF protein-expressing cells were significantly greater in placentae from HIV-1-infected women who did not transmit HIV-1 to their fetuses compared with women who transmitted the infection, but they were not significantly different from placentae of uninfected mothers. These findings demonstrate a novel pathway for endogenous HIV suppression that may prove to be an effective immune therapy for HIV infection.

Up-regulation of CCR5 expression in the placenta is associated with human immunodeficiency virus-1 vertical transmission

The role of placenta in vertical transmission is not yet fully understood. A protective role of the placenta during gestation is suggested by the finding that caesarian sections reduce the risk of transmission of human immunodeficiency virus (HIV)-1 from mother to child three- to fourfold. Here we investigated whether the immunological milieu of the placenta might be important in HIV-1 transmission. In situ imaging of immunohistochemically stained placenta sections and reverse transcriptase-polymerase chain reaction demonstrated a fourfold increase in CCR5:CXCR4 expression ratio in placentae from transmitting women compared to placentae from nontransmitting women. This chemokine receptor repertoire was consistent with an up-regulation of interleukin-4 and interleukin-10 expression in placentae from nontransmitting placentae compared to transmitting placentae. In situ imaging demonstrated that CCR5 and CXCR4 were expressed on placental macrophages and lymphocytes but not in trophoblasts. Simultaneous immunofluorescence/ultrasensitive in situ hybridization for HIV-1 gag-pol mRNA revealed that HIV-1 infects primarily CXCR4-expressing cells in placentae from nontransmitting women whereas predominantly CCR5-expressing cells were infected in placentae from transmitting women. These data are consistent with transmission of a homogeneous population of nonsyncytium-inducing HIV-1 isolates that use CCR5 as co-receptor.

Altered viral fitness of HIV-1 following failure of protease inhibitor-based therapy

HIV-1 isolated from patients with improved CD4+ T-cell counts despite virologic failure on a nucleoside reverse transcriptase inhibitor (NRTI) and protease inhibitor (PI)-containing regimen were characterized. Five paired virus isolates from patients before and after zidovudine, lamivudine, and ritonavir treatment were tested. Human peripheral blood leukocyte-reconstituted severe combined immunodeficient (hu-PBL-SCID) mice were infected with pre-or posttreatment isolates and plasma HIV-1 RNA levels and CD4+ T cells were measured. Two of five post-treatment isolates exhibited decreased replication in hu-PBL-SCID mice compared with the paired pretreatment isolate, and both had the V82A mutation in protease associated with resistance to PI. One additional posttreatment isolate with the M184V mutation in reverse transcriptase showed diminished replication. CD4+ T-cell depletion was similar following infection with either the pre-or posttreatment isolates. Subtle losses in the replication capacity of PI-or NRTI-resistant viruses may contribute to relative preservation of CD4+ T-cell counts in persons who experience virologic failure. Cytopathic effects of viral infection for target T cells vary from patient to patient but appear not to be influenced by mutations associated with failure of therapy in this system.

Cellular restoration in HIV infected persons treated with abacavir and a protease inhibitor: age inversely predicts naive CD4 cell count increase

OBJECTIVE

To characterize early and later indices of cellular restoration among HIV-1 infected persons treated with abacavir and one protease inhibitor and to identify predictors of CD4 cell increases.

METHODS

Flow-cytometric analyses of lymphocyte phenotypes among 71 antiretroviral treatment naive adults in a 48 week treatment trial.

RESULTS

During the first 4 weeks of therapy, increases in naive and memory CD4 cells and in B cells were seen; naive CD8 cells increased while CD8 cells remained stable as memory CD8 cells decreased. During the second phase total CD4 and naive CD4 and CD8 cells increased while total CD8 and memory CD8 cells decreased. The numbers of CD4 cells that expressed CD28 increased from a median of 308 x 10(6)/l at baseline to 477 x 10(6)/l at week 48. Higher baseline plasma HIV-1 RNA levels predicted the magnitude of early CD4 (r = 0.35; P = 0.01), memory CD4 (r = 0.38; P = 0.001) and CD28 CD4 cell (r = 0.29; P = 0.01) restoration but was not related to second phase changes. Younger age predicted a greater second phase (but not first phase) increase in naive CD4 cells (r = -0.31; P = 0.03).

CONCLUSIONS

Higher baseline levels of HIV-1 replication determine the magnitude of first phase CD4 cell increases after suppression of HIV-1 replication. Second phase (primarily naive) CD4 cell increases are not related to HIV-1 replication but are inversely relate to age suggesting that thymic potential is a major determinant of long term cellular restoration in HIV-1 infected persons receiving antiretroviral therapy.

T cell responses to recall antigens, alloantigen, and mitogen of HIV-infected patients receiving long-term combined antiretroviral therapy

The effect of highly active antiretroviral therapy (HAART) on T cell responses in 30 HIV-infected patients was studied. Lymphocyte proliferation in response to influenza A virus, HIV-1 p24, gp160, allogeneic leukocytes, and mitogen, as well as influenza-specific cytotoxic T lymphocyte (CTL) responses, were measured. AIDS patients had decreased T cell-proliferative responses to influenza and alloantigen compared with asymptomatic patients. Absence of positive proliferative responses of HIV-infected patients to HIV-1 antigens was not associated with increased interleukin 10 production. Correlation was observed between influenza-specific CTL response and T cell proliferation, as well as CD4+ T lymphocyte counts, indicating the importance of CD4+ helper T cells for generating antiviral CTL responses. Finally, these results show that HAART-treated asymptomatic patients, but not AIDS patients, have T cell responses comparable to those of control individuals. It remains to be determined whether immune-based therapy will contribute any additional benefit to patients who received HAART.

Evaluation of thymopoiesis using T cell receptor excision circles (TRECs): differential correlation between adult and pediatric TRECs and naïve phenotypes

To determine whether the thymus is still functional despite age-related involution, we measured a biomarker for thymopoiesis known as the T cell receptor excision circle (TREC) from peripheral blood mononuclear cells (PBMCs) of 148 healthy children and from PBMCs, CD4(+), and CD8(+) cells of 32, 30, and 50 healthy adults, respectively. We demonstrate that during the first 5 years of life, thymic output is decreased (P 0.002) but not dramatically (r = -0. 282). Among adults aged 23-58, thymic output was inversely correlated with age, as measured from PBMCs (r = -0.628, P < 0.0005), CD4(+) (r = -0.530, P 0.003), and CD8(+) fractions (r = -0.385, P 0. 006). A strong correlation existed between pediatric PBMC TRECs and the expression of three naïve phenotypic markers (CD45RA(+)CD45RO(-), CD45RA(+)CD62L(+), and CD45RO(-)CD27(+)CD95(low)). Adult PBMC TRECs correlated only with the expression of CD45RA(+)CD45RO(-) (r = 0.459, P 0.012). Our data suggest that in adults CD45RA(+)CD45RO(-) may be enriched for TRECs and add to a growing body of evidence illustrating intact thymic function in adulthood.

Mechanisms of HIV-associated lymphocyte apoptosis

Infection with the human immunodeficiency virus (HIV) is associated with a progressive decrease in CD4 T-cell number and a consequent impairment in host immune defenses. Analysis of T cells from patients infected with HIV, or of T cells infected in vitro with HIV, demonstrates a significant fraction of both infected and uninfected cells dying by apoptosis. The many mechanisms that contribute to HIV-associated lymphocyte apoptosis include chronic immunologic activation; gp120/160 ligation of the CD4 receptor; enhanced production of cytotoxic ligands or viral proteins by monocytes, macrophages, B cells, and CD8 T cells from HIV-infected patients that kill uninfected CD4 T cells; and direct infection of target cells by HIV, resulting in apoptosis. Although HIV infection results in T-cell apoptosis, under some circumstances HIV infection of resting T cells or macrophages does not result in apoptosis; this may be a critical step in the development of viral reservoirs. Recent therapies for HIV effectively reduce lymphoid and peripheral T-cell apoptosis, reduce viral replication, and enhance cellular immune competence; however, they do not alter viral reservoirs. Further understanding the regulation of apoptosis in HIV disease is required to develop novel immune-based therapies aimed at modifying HIV-induced apoptosis to the benefit of patients infected with HIV.

Hormonal levels among HIV-1-seropositive women compared with high-risk HIV-seronegative women during the menstrual cycle. Women's Health Study (WHS) 001 and WHS 001a Study Team

There is a paucity of normative data on hormonal levels among HIV-infected women. Hormonal levels may influence fertility and HIV-related immunological and virological factors. The objective of this study was to determine progesterone and estradiol levels during the menstrual cycle in HIV-seropositive women compared with high-risk seronegative women. The study enrolled 55 HIV-infected and 10 high-risk uninfected women with self-reported regular menstrual cycles (25-30-day cycles). Progesterone and estradiol levels were determined on a weekly basis for 8 weeks. The analysis included evaluations from the first complete menstrual cycle for the 54 HIV-infected and 9 uninfected women who had at least one complete cycle. The median age was 35 years for HIV-infected women and 36 years for uninfected women. The median CD4+ count for HIV-seropositive women was 210 cells/mm3. The median menstrual cycle length was 28 days (range 22-49 days) for HIV-infected women and 25 days (range 24-44 days) for uninfected women. The maximum progesterone level during the luteal phase was normal (>3.0 ng/ml) for 52 (96%) of 54 HIV-seropositive women and 7 (78%) of 9 HIV-seronegative women (p = 0.09, Fisher's exact test). The median maximum progesterone level was 12.2 ng/ml in HIV-seropositive women and 7.2 ng/ml in HIV-seronegative women (p = 0.07, Wilcoxon test). The median maximum estradiol value during the follicular phase was 148 pg/ml for HIV-seropositive women and 111 pg/ml for HIV-seronegative women (p = 0.04, Wilcoxon test). Among HIV-infected women, there were no significant differences in progesterone and estradiol levels by antiretroviral therapy, baseline plasma viral load, or median CD4+ cell count. We conclude that HIV-infected women with self-reported normal menstrual cycles have normal levels of progesterone and estradiol during the menstrual cycle.

Normalization of immune activation in lymphoid tissue following highly active antiretroviral therapy

Although significant progress has been made in understanding immune reconstitution in peripheral blood following highly active antiretroviral therapy (HAART), less is known about immune changes in lymphoid tissue. Here, the expression of cytokine proteins (interferon gamma [IFN-gamma], interleukin [IL]-2, IL-4, IL-10, IL-1alpha, and IL-1beta) and surface antigens (CD4, CD8, CD1a, CD68) as well as cellular proviral HIV-1 DNA were determined in sequential tonsil biopsies before and at 4, 12, and 48 to 56 weeks posttherapy by quantitative in situ image analysis and fluorescent in situ 5;-nuclease assay (FISNA). Despite plasma virus suppression, a fraction of tonsil cells harbored pro-viral DNA for up to 1 year. A fourfold to eightfold increase in CD8+ T cells in tissue compared with seronegative controls and an increased frequency of CD1a+ dendritic cells prior to HAART reached control levels at week 56. The frequency of IFN-gamma expressing cells was 10-to 15-fold higher than controls before therapy and was comparable with findings in seronegative controls by week 56. Elevated baseline expression of IL-1alpha and IL-1beta was reduced by week 4 but IL-1alpha levels remained elevated in 1 of 3 patients at week 56. These findings suggest that with effective viral suppression the immune system in tissue may return to a more resting state.

Effect of menstrual cycle on HIV-1 levels in the peripheral blood and genital tract. WHS 001 Study Team

OBJECTIVE

To assess the variation in HIV-1 over the menstrual cycle, including RNA levels in the female genital tract, plasma HIV-1-RNA levels, CD4 cell counts, and culturable virus.

DESIGN

A prospective analysis of 55 HIV-1-infected women.

METHODS

Blood and genital tract specimens were collected weekly over 8 weeks, spanning two complete menstrual cycles. Applying repeated-measures models that used menses as the reference level, the variation in viral RNA levels was compared in endocervical canal fluid and cells (collected by Sno-strips and cytobrush, respectively) and ectocervicovaginal lavage (CVL) fluid. Repeated-measures models were also used to assess the variation in plasma CD4 cell counts and viral load.

RESULTS

Shedding patterns differed among the three sampling methods, independent of genital tract co-infections. Genital tract HIV-1-RNA levels from CVL fluid and endocervical canal cytobrush specimens were highest during menses and lowest immediately thereafter (P = 0.001 and P = 0.04). The HIV-1-RNA level in endocervical canal fluid was highest in the week preceding menses (P = 0.003). The menstrual cycle had no effect on blood levels of RNA (P = 0.62), culturable virus (P = 0.34), or CD4 cell counts (P = 0.55). HIV-1-RNA levels were higher in endocervical canal fluid than in peripheral blood plasma during the late luteal phase (P = 0.03).

CONCLUSION

HIV-1-RNA levels vary with the menstrual cycle in the female genital tract but not the blood compartment. HIV-1-RNA levels are higher in endocervical canal fluid than in blood plasma. These findings may have important implications for sex-specific pathogenesis, heterosexual transmission, and contraceptive hormone interventions in HIV-1-infected women.

Shipment impairs lymphocyte proliferative responses to microbial antigens

Lymphocyte proliferation assays (LPAs) are widely used to assess T-lymphocyte function of patients with human immunodeficiency virus infection and other primary and secondary immunodeficiency disorders. Since these assays require expertise not readily available at all clinical sites, specimens may be shipped to central labs for testing. We conducted a large multicenter study to evaluate the effects of shipping on assay performance and found significant loss of LPA activity. This may lead to erroneous results for individual subjects and introduce bias into multicenter trials.

The impact of the ovulatory cycle on cytokine production: evaluation of systemic, cervicovaginal, and salivary compartments

To understand the impact of the menstrual cycle on immunologic parameters, we measured the level of cytokines and chemokines from plasma, cervicovaginal lavage (CVL), and saliva samples of 6 premenopausal women during the follicular and luteal phases of the ovulatory cycle. We demonstrate that the level of plasma interleukin-8 (IL-8) was 4-fold higher during the follicular phase than the luteal phase (p = 0.004), whereas plasma IL-1beta, IL-4, IL-6, IL-10, interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-1alpha (MIP-1alpha), and TNF receptor II (TNFR II) were not altered during the ovulatory cycle. In the vaginal compartment, as measured from CVL samples, the levels of IL-6 and IL-1beta were both 5-fold higher in the follicular than the luteal phase (p = 0.0002 and 0.03, respectively). Salivary cytokine and chemokine samples were similar when measured during the luteal and the follicular phases. Additional analysis of lymphocyte subsets for phenotypic and functional markers indicated that they were not influenced by the ovulatory cycle. Collectively, these data suggest that IL-6, IL-8, and IL-1beta are differentially regulated during the ovulatory cycle.

Need for an external proficiency testing program for cytokines, chemokines, and plasma markers of immune activation

An external evaluation program for measuring the performance of laboratories testing for cytokines and immune activation markers in biological fluids was developed. Cytokines, chemokines, soluble cytokine receptors, and other soluble markers of immune activation (CSM) were measured in plasma from a healthy human immunodeficiency virus (HIV)-seronegative reference population and from HIV-seropositive individuals as well as in supernatant fluids from in vitro-stimulated human immune cells. The 14 components measured were tumor necrosis factor (TNF) alpha, gamma interferon, interleukin-1 (IL-1), IL-2, IL-4, IL-6, IL-10, Rantes, MIP-Ia, MIP-Ibeta, soluble TNF receptor II, soluble IL-2 receptor alpha, beta(2)-microglobulin, and neopterin. Twelve laboratories associated with the Adult and Pediatric AIDS Clinical Trial Groups participated in the study. The performance features that were evaluated included intralaboratory variability, interlaboratory variability, comparison of reagent sources, and ability to detect CSM in the plasma of normal subjects as well as the changes occurring in disease. The principal findings were as follows: (i) on initial testing, i.e., before participating in the program, laboratories frequently differed markedly in their analytic results; (ii) the quality of testing of a CSM in individual participating laboratories could be assessed; (iii) most commercial kits allowed distinction between normal and abnormal plasma CSM levels and between supernatants of stimulated and unstimulated cells; (iv) different sources of reagents and reference standards frequently provided different absolute values; (v) inexperienced laboratories can benefit from participating in the program; (vi) laboratory performance improved during active participation in the program; and (vii) comparability between analyses conducted at different sites can be ensured by an external proficiency testing program.

Maximum suppression of HIV replication leads to the restoration of HIV-specific responses in early HIV disease

OBJECTIVES

It is predicted that HIV-infected individuals in early HIV disease are the most likely group to achieve immune reconstitution following highly active antiretroviral treatment. We assessed whether suppression of HIV replication in this group would improve immune function.

METHODS

Seventeen antiretroviral-naïve patients in early HIV disease were evaluated for immune function and lymphocyte phenotyping using standard immunological assays.

RESULTS

Absolute CD4+ T-cell number increased from a median of 550 to 800 x 10(6) cells/l while CD8+ T-cell numbers were reduced. The decrease in CD8+ cells correlated with a decrease in the CD8+ memory phenotype. Kinetics of CD4+ naïve and memory T-cell rise indicated that 80% of the maximum CD4+ naïve increase was achieved within 18 weeks whereas maximum CD4+ memory T-cell rise was achieved within 36 weeks. Activation markers (HLA-DR, CD38) and an apoptosis-related marker (CD95) were reduced on CD4+ and CD8+ T cells. Lymphocyte proliferation responses to tetanus toxoid, alloantigen, and anti-CD3/CD28 were restored in patients that were initially unresponsive. At baseline, 31% of the patients responded to HIV p24, which increased to 69% post-therapy. The inducible RANTES response was normalized following therapy whereas inducible interferon-gamma, interleukin (IL)-12, and MIP1beta were elevated. The depressed inducible IL-10 response, however, was not altered after therapy.

CONCLUSIONS

This is one of the first studies to demonstrate the restoration of HIV-1 specific responses in non-acute HIV infection, suggesting early intervention with potent antiretroviral therapy may reverse immune-mediated damage not seen with treated patients who have more advanced disease.

Preservation of lymphocyte immunophenotype and proliferative responses in cryopreserved peripheral blood mononuclear cells from human immunodeficiency virus type 1-infected donors: implications for multicenter clinical trials. The ACTG Immunology Advanced Technology Laboratories

Human immunodeficiency virus type 1 (HIV-1) infection results in impaired immune function that can be measured by changes in immunophenotypically defined lymphocyte subsets and other in vitro functional assays. These in vitro assays may also serve as early indicators of efficacy when new therapeutic strategies for HIV-1 infection are being evaluated. However, the use of in vitro assays of immune function in multicenter clinical trials has been hindered by their need to be performed on fresh specimens. We assessed the feasibility of using cryopreserved peripheral blood mononuclear cells (PBMC) for lymphocyte immunophenotyping and for lymphocyte proliferation at nine laboratories. In HIV-1-infected patients with moderate CD4(+) lymphocyte loss, the procedures of density gradient isolation, cryopreservation, and thawing of PBMC resulted in significant loss of CD19(+) B cells but no measurable loss of total T cells or CD4(+) or CD8(+) T cells. No significant changes were seen in CD28(-) CD95(+) lymphocytes after cell isolation and cryopreservation. However, small decreases in HLA-DR(+) CD38(+) lymphocytes and of CD45RA(+) CD62L(+) were observed within both the CD4(+) and CD8(+) subsets. Fewer than 10% of those specimens that showed positive PBMC proliferative responses to mitogens or microbial antigens lost their responsiveness after cryopreservation. These results support the feasibility of cryopreserving PBMC for immunophenotyping and functional testing in multicenter AIDS clinical trials. However, small changes in selected lymphocyte subsets that may occur after PBMC isolation and cryopreservation will need to be assessed and considered in the design of each clinical trial.

Detection of T cell receptor circles (TRECs) as biomarkers for de novo T cell synthesis using a quantitative polymerase chain reaction-enzyme linked immunosorbent assay (PCR-ELISA)

Currently, phenotypic markers that distinguish between recent thymic emigrants/de novo T cells and the rest of the peripheral T cell pool are lacking. This distinction is critical in studies aimed at evaluating immune reconstitution following intensive chemotherapy, in immunodeficiency-related therapies, or in the elucidation of the kinetics of thymic function. During V(D)J T cell receptor rearrangement, DNA extrachromosomal excision products are generated. These products, known as T cell receptor excision circles (TRECs), are not replicated during mitosis and are thus diluted with each round of cell division. Therefore, TRECs can be used as an indicator of recent thymic emigrants. Thus far, quantitative competitive-polymerase chain reaction (QC-PCR) and real time PCR were used to measure TREC levels. However, QC-PCR relies on radioactivity, is cumbersome when processing many samples at once and the cost of real time PCR does not make it a viable option for many laboratories. We describe here the development of a quantitative PCR-ELISA method for the measurement of coding joint TRECs generated from ValphaJalpha recombination. Our assay is ultra sensitive, relies on biotin labeling rather than radioactivity, is based on a 96-well format making multiple process sampling relatively easy, and is cost effective. Using this PCR-ELISA method, we evaluated thymic output among 22 normal subjects, ranging in age from 22-53 years, and among HIV-infected individuals following highly active antiretroviral therapy (HAART). We demonstrate that an inverse relationship exists between TREC levels and aging in normal individuals and that, among some HIV patients, HAART treatment leads to enhanced thymic output. Our assay has direct relevance in projects examining normal and abnormal thymic function and in immune reconstitution studies.

Effect of zidovudine resistance mutations on virologic response to treatment with zidovudine-lamivudine-ritonavir: genotypic analysis of human immunodeficiency virus type 1 isolates from AIDS clinical trials group protocol 315.ACTG Protocol 315 Team

The effect of baseline drug resistance mutations on response to zidovudine, lamivudine, and ritonavir was evaluated in zidovudine-experienced persons infected with human immunodeficiency virus type 1 (HIV-1). Presence of the K70R mutation was associated with significantly higher plasma HIV-1 RNA levels at baseline. However, presence of resistance mutations did not affect the increase in plasma HIV-1 RNA during a 5-week drug washout, nor was there any effect on first-phase virus decay rates after initiation of therapy or on the probability of having plasma HIV-1 RNA levels <100 copies/mL at week 48. Polymorphisms at protease codons 10, 36, and 71 were associated with significantly faster second-phase decay rates. Suppression of plasma HIV-1 RNA despite presence of zidovudine resistance mutations implies that the presence of these mutations does not preclude a durable response to treatment with a potent 3-drug regimen.

Response to immunization with recall and neoantigens after prolonged administration of an HIV-1 protease inhibitor-containing regimen. ACTG 375 team. AIDS Clinical Trials Group

OBJECTIVES

To ascertain if immunization results in the restoration of responses to recall antigens, in the development of responses to presumed neoantigens, and to identify the virologic and immunologic correlates of these responses in persons with HIV-1 infection.

DESIGN AND SETTING

Open-label study carried out at three university-affiliated AIDS Clinical Trials Units in the United States.

SUBJECTS AND METHODS

Thirty-one subjects participating in AIDS Clinical Trials Group Protocol 375 who had received zidovudine, lamivudine, and ritonavir for at least 48 weeks. Subjects were immunized with tetanus toxoid (TT) at entry and with inactivated hepatitis A vaccine (hep A) and keyhole limpet hemocyanin (KLH) at entry and 6 weeks. The development of antibody, lymphocyte proliferative assay (LPA), and delayed-type hypersensitivity (DTH) responses after immunization were monitored.

RESULTS

The LPA and DTH responses to TT improved in 57 and 68% of participants, respectively; 73 and 65% developed enhanced LPA and DTH responses to KLH. Forty-eight percent of patients developed a four-fold increase in antibody concentration to tetanus. Seventy-three percent of patients without detectable hepatitis A antibodies at baseline developed antibodies after immunization. Eighty-three percent of patients experienced at least a four-fold rise in KLH antibody concentration. Immune activation and viral load predicted poor recall responses and the number of memory CD4+ T-cells predicted good responses to recall antigens. Naïve CD4+ T-cell numbers, decrease in viral load, increases in CD4+ and CD28+ cells, and decreases in immune activation were associated with responses to presumed neoantigens.

CONCLUSIONS

Most HIV-infected patients treated with potent combination antiretrovirals develop responses to recall and presumed neoantigens after immunization. Functional immune restoration in response to immunization is related to control of viral replication, decreased immune activation as well as to both quantitative and qualitative restoration of circulating T- lymphocyte subpopulations.

Immune reconstitution in the first year of potent antiretroviral therapy and its relationship to virologic response

The effects of 1 year of zidovudine, lamivudine, and ritonavir treatment on immune reconstitution were evaluated in 34 human immunodeficiency virus (HIV)-infected individuals. After 48 weeks of therapy, 20 (59%) subjects had <100 copies HIV RNA/mL. CD4+ T cells increased from a median of 192/mm3 at baseline to 362/mm3 at week 48. Lymphocyte proliferative responses to Candida normalized within 12 weeks, but responses to HIV and tetanus remained depressed throughout therapy. Alloantigen responses increased within 12 weeks and then declined to baseline levels. Recovery of delayed-type hypersensitivity responses occurred after 12 weeks for Candida and after 48 weeks for mumps. The magnitude of virologic suppression was correlated with numeric increases in CD4+ T cells, but not with measures of functional immune reconstitution. Plasma virus suppression <100 copies/mL was not significantly correlated with increases in CD4+ T cells or functional immune reconstitution.

Thymic size and lymphocyte restoration in patients with human immunodeficiency virus infection after 48 weeks of zidovudine, lamivudine, and ritonavir therapy

Human immunodeficiency virus (HIV) infection is associated with progressive loss of circulating CD4+ lymphocytes. Treatment with highly active antiretroviral therapy (HAART) has led to increases in CD4+ T lymphocytes of naive (CD45RA+62L+) and memory (CD45R0+RA-) phenotypes. Thymic computerized tomography scans were obtained on 30 individuals with HIV disease to investigate the role of the thymus in cellular restoration after 48 weeks of HAART. Individuals with abundant thymic tissue had higher naive CD4+ T lymphocyte counts at weeks 2-24 after therapy than individuals with minimal thymic tissue. Individuals with abundant thymic tissue had significantly larger increases in naive CD4+ cells during the first 4 weeks of therapy. These individuals were also more likely to experience viral rebound despite comparable initial declines in plasma HIV-1 RNA. These findings suggest that there is a complex relationship among the thymus, viral replication, and lymphocyte restoration after application of HAART in HIV disease.

Changes in human immunodeficiency virus type 1 virus load during mobilization and harvesting of hemopoietic progenitor cells. Adult AIDS Clinical Trials Group 285 Study Team

Genetic modification of hemopoietic progenitor cells ex vivo, followed by the infusion of the genetically modified cells into the human immunodeficiency virus-1 (HIV-1) infected donor, has been proposed as a treatment for HIV-1 infection. The current study was undertaken to evaluate the effect of hemopoietic stem cell mobilization and harvesting on HIV-1 replication in persons with HIV-1 infection. Eighteen HIV-1-infected persons received recombinant granulocyte colony-stimulating factor (G-CSF; Filgrastim) 10 microg/kg per day, for 7 days. On days 4 and 5, peripheral blood mononuclear cells were harvested by leukapheresis. The CD4+ lymphocyte count at entry was >500/microL for 6 subjects, 200 to 500/microL for 6 subjects, and <200/microL for 6 subjects. For 9 of 18 subjects, plasma HIV-1 RNA levels increased 4- to 100-fold (>0.6 log(10)) above baseline between days 4 and 7 and returned to baseline by day 27. Significant increases of plasma HIV-1 RNA levels occurred in 5 subjects despite 3-drug antiretroviral therapy. Changes in CD4+ and CD34+ cells during mobilization and harvesting were similar in all subjects whether they had or did not have increased plasma HIV-1 RNA levels. Thus, mobilization and harvesting of bone marrow progenitor cells from persons infected with HIV-1 induced a transient increase in viral replication in some patients but was not associated with adverse effects. (Blood. 2000;95: 48-55)

Reduced mobilization of CD34+ stem cells in advanced human immunodeficiency virus type 1 disease

Granulocyte colony-stimulating factor (r-met Hu G-CSF; filgrastim; 10 microgram/kg/day for 7 days) was used to mobilize CD34+stem cells into the peripheral blood of human immunodeficiency virus type 1 (HIV-1)-infected individuals and a group of HIV-1-uninfected donors as a measure of immunologic reserve in HIV-1-infected people. G-CSF mobilized CD34+ cells of HIV-1-infected individuals with cell counts >500 CD4+ cells/mm3, as well as in HIV-1-uninfected donors. In contrast, CD34 cell mobilization was significantly blunted in HIV-1-infected individuals with cell counts <500 CD4+ cells/mm3 (<200 cell days vs. >650 cell days, P<.0005, compared with the >500 CD4+ cell cohort). At least 1.75x10(7) CD34 cells were harvested by leukapheresis from patients in each study cohort. CD34+ cell viability and the ability to differentiate precursor cells into myeloid and erythroid progenitor cells were not affected by HIV-1 infection.

Normal immune function of monocyte-derived dendritic cells from HIV-infected individuals: implications for immunotherapy

Dendritic cells (DC) are the most potent cells involved in the generation of primary and secondary immune responses. To assess the feasibility of using autologous DC as immunotherapy for HIV disease, we analyzed a variety of immune parameters using DC isolated from HIV-infected (HIV+) individuals, as well as DC obtained from HIV-uninfected (HIV-) individuals infected in vitro with HIV. After stimulation with recombinant CD40 ligand (CD40LT), cytokine and beta-chemokine production were similar by DC from HIV- donors infected in vitro with the CCR5-using HIV Ba-L strain (n = 8) compared with uninfected DC from the same donors. Production of beta-chemokines, but not of cytokines, was increased by a CXCR4-using IIIB strain-infected DC (n = 7). Stimulation of HIV-infected DC with CD40LT decreased infection in Ba-L-infected DC, but had no effect on IIIB-infected DC. Consistent with this finding, CD40LT down-regulated CCR5 and up-regulated CXCR4 expression on DC. Monocyte-derived DC were also propagated from 15 HIV+ and 13 HIV- donors. They exhibited similar expression of costimulatory molecules and produced similar amounts of IL-12, IL-10, and beta-chemokines, following stimulation. By contrast, stimulated PBMC from HIV+ patients exhibited decreased IL-12 and increased IL-10 production. In summary, phenotype, cytokine secretion, and beta-chemokine production by DC from HIV+ individuals were normal. These cells may prove useful in boosting cellular immune responses in HIV+ individuals.

Perforin is not co-expressed with granzyme A within cytotoxic granules in CD8 T lymphocytes present in lymphoid tissue during chronic HIV infection

BACKGROUND

Residual HIV-1-infected cells are poorly eliminated from lymphoid tissue (LT) reservoirs by effector cytotoxic T lymphocytes (eCTL) despite antiretroviral therapy. Perforin and granzyme A (grA) constitute major effector molecules within eCTL granules that induce apoptosis and lysis of virally infected cells.

OBJECTIVE

Expression of perforin and grA was studied at the single cell level in LT and blood from 16 patients infected with HIV-1 (stage A1-C) who were not taking antiretroviral therapy.

METHOD

Immunohistochemical analysis by in situ imaging of cells from blood and LT.

RESULTS

Quantitative in situ imaging showed that perforin-expressing CD8 T cells comprised 0.3-1.5% of total cells within the LT from recent HIV-1 seroconverters, while grA was found in 2.1-7.2% of total cells. However, despite high-level grA upregulation (1.5-4.5% of total cells) compared with that in non-infected individuals (0.4-0.9%), perforin expression remained low (< 0.1% of total cells) (P < 0.02) in LT from patients with chronic HIV-1 infection (stage A2-C). This contrasted with findings in peripheral blood mononuclear cells (PBMC) from the same HIV-1 infected cohort where perforin was detected in 13-31% of all PBMC, which was 10- to 100-fold higher than in lymphoid tissue (P < 0.001); grA was found in 14-32% of total PBMC. Two-colour staining showed that granular expression of perforin and grA was restricted to CD8 T cells in over 90% of total cells in both LT and blood.

CONCLUSIONS

These findings indicate that cytotoxic perforin expression is impaired at local sites of HIV replication within lymphoid tissue. Since perforin is required together with grA for granule-mediated cytolysis, the low perforin expression in the LT may limit the ability of eCTL to eliminate HIV-1 infected cells in lymphoid tissue.

HIV infection perturbs DNA content of lymphoid cells: partial correction after 'suppression' of virus replication

OBJECTIVE

To examine the DNA content of circulating lymphocytes obtained from HIV-1-infected persons and to explore the effects of antiretroviral therapy on these indices.

DESIGN

Cross-sectional analysis and 48-week open label treatment trial (AIDS Clinical Trials Group Protocol 315) of zidovudine, lamivudine and ritonavir.

METHODS

Peripheral blood lymphocytes were obtained from HIV-1-infected patients and healthy controls and after 48 h of in vitro cultivation were stained with propidium iodide and analyzed for DNA content by flow cytometry.

RESULTS

HIV-1-infected patients had more hypodiploid cells (19%), fewer G0-G1 phase cells (70%) and more S phase cells (10%) than did healthy controls (8%, 85% and 5% respectively; P = 0.002). Patients with sustained suppression of plasma HIV-1 RNA levels after antiretroviral therapy had only modest improvements in these indices. In contrast, patients who failed to suppress plasma HIV-1 RNA levels had decreases in G0-G1 cells to 54% (P = 0.032) and increases in S phase cells to 24% (P = 0.055). Plasma HIV-1 RNA levels and the percentage of S phase cells were correlated (r, 0.23; P = 0.047). In patients failing antiretroviral therapy, there was an inverse correlation between the percentage of G0-G1 cells and expression of the activation antigens CD38 and HLA-DR on CD4 cells (r, -0.409; P = 0.016) and CD8 cells (r, -0.363; P = 0.035).

CONCLUSIONS

Lymphocytes obtained from HIV-1-infected patients display perturbations in DNA content after brief cultivation in vitro reflective of immune activation in vivo. The marginal improvement in these indices after 'successful' suppression of HIV-1 replication suggests that even low levels of HIV-1 replication are sufficient to induce immune activation and perturbations in DNA content.

Increases in T cell telomere length in HIV infection after antiretroviral combination therapy for HIV-1 infection implicate distinct population dynamics in CD4+ and CD8+ T cells

Changes in mean telomeric terminal restriction fragment (TRF) length were examined as a marker for cellular replicative history in HIV-1-infected individuals after institution of anti-retroviral therapy (ART). Increases in mean T cell TRF lengths were observed in most patients following therapy; however, the contribution of individual T cell subsets was complex. An elongation of CD8+ T cell TRF was nearly uniformly observed while changes in mean TRF length in CD4+ T cells were heterogeneous as, despite potent suppression of viral replication, CD4 cell telomeres recovered in some patients, yet continued to decline in others. Increases in CD8 cell TRF correlated with decreased memory cells, suggesting a negative selection in the periphery for CD8 cells with extensive replicative history. In contrast, increases in CD4+ T cell TRF length correlated with increases in naive cell subsets, suggesting that the CD4+ T cell TRF increase may reflect a thymic contribution in some patients. These are the first increases in somatic cell telomere length in a population of cells observed in vivo, and the findings are compatible with therapy-induced reconstitution of the lymphoid compartment with cells having a more extensive replicative potential. These findings further distinguish lymphocytes from other somatic cell populations where only decreases in TRF over time have been noted. Thus, institution of ART in persons with moderately advanced HIV-1 disease reveals distinct population dynamics of CD4 and CD8 T cell subsets and also shows that the lymphocyte replicative history is dynamic.

Bacterial vaginosis-associated microflora isolated from the female genital tract activates HIV-1 expression

Alteration of cervicovaginal microbial flora can lead to vaginosis, which is associated with an increased risk of HIV-1 transmission. We recently characterized a soluble HIV-inducing factor (HIF) from the cervicovaginal lavage (CVL) samples of women. The goals of this study were to determine the effect of cervicovaginal microflora on HIV-1 expression and to elucidate the relationship between HIF activity and microflora. Physiologically relevant microorganisms, Mycoplasma, diphtheroid-like bacteria, Gardnerella vaginalis, Streptococcus agalactiae, and Streptococcus constellatus, cultured from the CVL of a representative woman with a clinical condition of bacterial vaginosis and possessing HIF activity, induced HIV-1 expression. The magnitude of virus induction varied widely with the greatest stimulation induced by diphtheroid-like bacteria and Mycoplasma. The transcriptional induction by Mycoplasma was mediated by activation of the KB enhancer, an activation mechanism shared with HIF. Also as with HIF, Mycoplasma induced AP-1 dependent transcription. Polymerase chain reaction (PCR)-based speciation showed that the isolate was M. hominis. Our data indicate that bacterial vaginosis-associated microflora can enhance HIV-1 transcription and replication and identify M. hominis as a potential source for HIF activity. The virus-enhancing activities associated with the microflora and HIF may increase genital tract viral load, potentially contributing to HIV transmission.

Effect of zidovudine postexposure prophylaxis on the development of HIV-specific cytotoxic T-lymphocyte responses in HIV-exposed healthcare workers

We evaluated the effects of zidovudine postexposure prophylaxis (PEP) on the development of human immunodeficiency virus (HIV) envelope-specific cytotoxic T-lymphocyte responses in 20 healthcare workers with occupational exposures to HIV. Seven healthcare workers were treated with zidovudine PEP. Only 1 of 7 treated, versus 6 of 13 not treated, developed an HIV envelope-specific cytotoxic T-lymphocyte response. These data suggest that zidovudine abrogated HIV-specific cytotoxic T-lymphocyte responses. HIV-specific cytotoxic T-lymphocyte responses may be useful as a surrogate marker of HIV replication in the evaluation of new regimens for PEP of occupational HIV exposures.