Monitoring HIV-1 treatment in immune-cell subsets with ultrasensitive fluorescence-in-situ hybridisation.
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Anti-HIV Agents↗
Biomedical subjects
A Landay
Publications and source records attributed to A Landay.
Characterization of viral dynamics in human immunodeficiency virus type 1-infected patients treated with combination antiretroviral therapy: relationships to host factors, cellular restoration, and virologic end points.
Biphasic plasma viral decays were modeled in 48 patients treated with ritonavir, zidovudine, and lamivudine. Estimated first- and second-phase decay rates were d1 as 0.47/day and d2 as 0.04/day. Interpatient differences in both decay rates were significant. The d1 was directly correlated with baseline CD4+, CD4+CD28+, and CD8+CD28+ T lymphocyte counts (P<.05) and inversely correlated with baseline virus load (P=.044) and the magnitude of CD4+ and CD8+ T lymphocyte recovery (P<.01). The d2 was directly correlated with baseline percentage of CD8+ T lymphocytes (P=.023), the CD8+CD38+ cell number (P=.024), and the level of IgG that binds to human immunodeficiency virus (HIV) type 1 gp120 (P=.02). Viral decay rates were not predictive of treatment failure or durability of viral suppression. These exploratory findings are consistent with a model in which immunologic factors contribute to elimination of HIV-infected cells and suggest a dynamic interplay between regulation of HIV expression and lymphocyte activation and recovery.
ADP-ribosyl Cyclase↗
Hepatitis G virus RNA is common in AIDS patients' plasma but is not associated with abnormal liver function tests or other clinical syndromes.
Hepatitis G virus (HGV) is a new virus found in 1% to 4% of blood from all donors but is more prevalent in some immunocompromised groups, with unclear clinical significance. Frozen plasma samples from 192 AIDS patients were tested for HGV RNA; 44 (23%) were positive. Positive patients did not differ from negative patients in age, gender, race, HIV infection risk factors, nor blood transfusion exposure. Hepatitis BsAg was associated with HGV infection (odds ratio [OR] = 7.7; 95% confidence interval [CI], 2.4-25.0) but hepatitis C antibody was not. Mean values for liver function tests and hematologic values did not differ significantly between the groups nor did the occurrence of certain recognized AIDS-related complications. Mean CD4+ cell counts and HIV-1 plasma RNA levels were comparable in the two groups, but the mean circulating CD8+ cell count in the HGV-positive group (853+/-458 cells/microL) was higher than in the negative group (682+/-457 cells/microL; p = .03). Hepatitis G virus, although common in AIDS patients, does not appear to alter the course of AIDS nor appear as a distinct hepatitis syndrome.
AIDS-Related Opportunistic Infections↗
Early reduction of immune activation in lymphoid tissue following highly active HIV therapy.
OBJECTIVE: To evaluate immune reconstitution within HIV-infected lymphoid tissue during highly active antiretroviral therapy (HAART). DESIGN AND METHODS: In situ cellular responses were studied in sequential tonsillar biopsies in three asymptomatic HIV-infected (CD4 cells greater than 400 x 10(6)/l) antiretroviral treatment-naive volunteers enrolled in a clinical trial to determine the early effect of HAART. Computerized image analysis was used to study immunohistochemically stained sequential tonsil sections for the patterns of local cytokine production, chemokine receptor expression and cellular distribution. Replicate quantitative assessments of samples before and after 4 weeks of therapy were used for the evaluation of drug effects and compared with four uninfected controls. Tonsillar HIV proviral-DNA was determined by fluorescent in situ 5'-nuclease assay. RESULTS: HIV-infected tonsil tissue was characterized by extensive pro-inflammatory and type 1 cytokine expression. A five- to 15-fold elevation of interleukin (IL)-1 alpha, IL-12, IL-2 and interferon (IFN)-gamma protein expression was found compared with controls, and each encompassed a mean of at least 4.5% of the tissue compartment. This was reduced by 20-90% in all individuals after 4 weeks of HAART. In contrast, type 2 cytokine expression (IL-4, IL-10), plus tumour necrosis factor (TNF)-alpha, remained low throughout the study. HAART reduced, by 40%, the expression of HIV co-receptors, CCR5 and CXCR4, which initially were elevated four to six times over the control values. In addition, the myelomonocytic inflammatory proteins, CD68 and calprotectin, diminished by 26-83% after therapy. The HIV RNA was reduced to undetectable levels in plasma by HAART. However, a large pool of tonsil cells (2-7%), remained HIV DNA positive after 4 weeks of therapy. CONCLUSIONS: Although immune activation may be the direct consequence of HIV replication, HAART-associated reconstitution begins with a reduction in inflammatory cytokine production which precedes the elimination of local proviral reservoirs.
Anti-HIV Agents↗
Recovery of the immune system with antiretroviral therapy: the end of opportunism?
OBJECTIVE: Clinical care of people infected with human immunodeficiency virus (HIV) has been substantially affected by the introduction of potent antiretroviral therapy. Changes in the immune system after such therapy and the clinical consequences are important issues for clinicians treating patients with HIV. DATA SOURCES: A systematic review of MEDLINE, 1993 to January 1998, of peer-reviewed publications, abstracts from national and international conferences, and product registration information through January 1998. STUDY SELECTION AND DATA EXTRACTION: Criteria used to select studies include relevance to immune reconstitution with potent antiretroviral therapy and having been published in the English language. Assessment of data quality and validity included consideration of venue of the publication and relevance to practice. DATA SYNTHESIS: Suppression of viral replication after administration of potent antiretroviral therapy that includes inhibitors of the HIV-1 protease is associated with quantitative and qualitative changes in the immune system. In patients with relatively advanced disease, there is a first-phase rise (during the initial 3 months) in both naive and memory CD4+ and CD8+ T lymphocytes and B lymphocytes. This is followed by a slower second-phase increase (after 3 months) in cells primarily of the naive CD4+ and CD8+ phenotypes. These quantitative changes are associated with qualitative improvements in host immune responses, best characterized by dramatically reduced risk of opportunistic infection. Restoration of the immune system during the first year of potent antiretroviral therapy is partial at best. CONCLUSIONS: Potent antiretroviral therapy has become the standard of care for people with HIV infection, and its use has led to significant reductions in the incidence of the acquired immunodeficiency syndrome (AIDS) and in mortality from HIV infection. Although incomplete, considerable immune recovery occurs, sufficient, in most cases, to provide adequate protection against most AIDS-associated opportunistic infections.
AIDS-Related Opportunistic Infections↗
In vivo analysis of Fas/FasL interactions in HIV-infected patients.
Recent insights into the pharmacological control of HIV replication and the molecular mechanisms of peripheral T cells homeostasis allowed us to investigate in vivo the mechanisms mediating T cell depletion in HIV-infected patients. Before the initiation of highly active antiretroviral therapy (HAART), a high degree of lymphoid tissue apoptosis is present, which is reduced upon HAART initiation (P < 0.001) and directly correlates with reduction of viral load and increases of peripheral T lymphocytes (P < 0.01). Because Fas/FasL interactions play a key role in peripheral T lymphocyte homeostasis, we investigated the susceptibility to Fas-mediated apoptosis in peripheral T lymphocytes and of FasL expression in lymphoid tissue before and during HAART. High levels of Fas-susceptibility found in peripheral CD4 T lymphocytes before HAART were significantly reduced after HAART, coinciding with decreases in viral load (P = 0.018) and increases in peripheral CD4 T lymphocyte counts (P < 0.01). However, the increased FasL expression in the lymphoid tissue of HIV-infected individuals was not reduced after HAART. These results demonstrate that lymphoid tissue apoptosis directly correlates with viral load and peripheral T lymphocyte numbers, and suggest that HIV-induced susceptibility to Fas-dependent apoptosis may play a key role in the regulation of T cell homeostasis in HIV-infected individuals.
Anti-HIV Agents↗
High prevalence of hepatitis G virus RNA and antibody to probable viral envelope protein but not both in AIDS patients' plasma.
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Acquired Immunodeficiency Syndrome↗
Repertoire of chemokine receptor expression in the female genital tract: implications for human immunodeficiency virus transmission.
Sexually transmitted diseases, genital ulcer disease, and progesterone therapy increase susceptibility to lentivirus transmission. Infection of cells by human immunodeficiency virus (HIV) is dependent on expression of specific chemokine receptors known to function as HIV co-receptors. Quantitative kinetic reverse transcription-polymerase chain reaction was developed to determine the in vivo expression levels of CCR5, CXCR4, CCR3, CCR2b, and the cytomegalovirus-encoded US28 in peripheral blood mononuclear cells and cervical biopsies from 12 women with and without sexually transmitted diseases, genital ulcer disease, and progesterone-predominant conditions. Our data indicate that CCR5 is the major HIV co-receptor expressed in the female genital tract, and CXCR4 is the predominantly expressed HIV co-receptor in peripheral blood. CCR5 mRNA expression in the ectocervix was 10-fold greater than CXCR4, 20-fold greater than CCR2b, and 100-fold greater than CCR3. In peripheral blood, CXCR4 expression was 1.5-fold greater than CCR5, 10-fold greater than CCR2b, and 15-fold greater than CCR3. US28 was not expressed in cervical tissue despite expression in peripheral blood mononuclear cells from five individuals. CCR5 was significantly increased (p < 0.02) in biopsies from women with sexually transmitted diseases and others who were progesterone predominant. In vitro studies demonstrate that progesterone increases CCR5, CXCR4, and CCR3 expression and decreases CCR2b expression in lymphocytes and monocytes/macrophages. Characterization of chemokine receptors at the tissue level provides important information in identifying host determinants of HIV-1 transmission.
Adult↗
Rationale for immune-based therapies for HIV-1 infection.
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Clinical Trials as Topic↗
Induction of HIV-1 replication by type 1-like cytokines, interleukin (IL)-12 and IL-15: effect on viral transcriptional activation, cellular proliferation, and endogenous cytokine production.
Cytokine dysregulation is evident in HIV-1 infection and it may play an important role in HIV-1 pathogenesis. Administration of T helper cytokines potentially may restore the functional abnormalities to the HIV-1 immune response. Type 1-like cytokines, IL-2, IL-12, and IL-15, are candidates for immune-based therapy for HIV. Given their potential therapeutic use, we determined the effects of IL-2, IL-12, and IL-15 on HIV-1 replication in both primary blood mononuclear cells (PBMC) and the T-cell line, Kit 225-K6. We demonstrate that both IL-2 and IL-12 induce a similar level of HIV-1 replication (9- and 11-fold, respectively) in mitogen-stimulated PBMC. The effect of IL-2 plateaued by day 6, while that of IL-12 continued to increase HIV-1 expression. IL-15 induced a 2.5-fold increase in HIV-1 expression that remained at the same level through day 6. In Kit 225-K6, an IL-2-dependent T cell line, IL-12 and IL-15 enhanced HIV-1 replication by 5- and 3.5-fold over IL-2-treated cultures, respectively. IL-2-, IL-12-, and IL-15-mediated induction of HIV was independent of direct HIV-1 LTR activation, since none of the cytokines induced LTR activity from transfected reporter gene constructs. The cytokine-mediated induction of HIV-1 expression was also independent of cellular proliferation. In PBMC, the IL-12-mediated effect was partially mediated by endogenous cytokine production of IL-1beta and IL-7, whereas in Kit 225-K6, TNFalpha, INFgamma, IL-1beta, and IL-7 did not contribute significantly to the IL-12-mediated effect. IL-15 effect on HIV-1 in PBMC was independent of endogenous cytokine production. However, in Kit 225-K6, neutralizing antibodies to IL-7 had a significant effect on HIV-1 expression. These data suggest that IL-2, IL-12, and IL-15 increase HIV-1 replication predominantly through a posttranscriptional mechanism that may be enhanced by endogenous cytokine production.
Antibodies, Viral↗
A human immunodeficiency virus (HIV)-inducing factor from the female genital tract activates HIV-1 gene expression through the kappaB enhancer.
Virus-enhancing factors present in the female genital tract may influence the transmission of human immunodeficiency virus type 1 (HIV-1). Previously, the presence of a heat-stable soluble factor in the cervicovaginal lavage (CVL) fluid of both HIV-infected and -uninfected women that induces HIV-1 expression in T cells and monocytes was reported. Now this CVL factor was shown to increase HIV-1 gene expression through the activation of the kappaB enhancer in the viral long terminal repeat (LTR). DNA binding studies, together with functional studies using mutant LTR reporter constructs, indicate the requirement for an NF-kappaB-dependent pathway in the CVL-mediated activation of HIV-1 expression. CVL samples that activated HIV-1 expression also stimulated AP-1-dependent transcription. These data demonstrate that an HIV-inducing factor, distinct from heat-labile cytokines, present in the female genital mucosa can activate AP-1 and NF-kappaB and increase HIV-1 gene expression through the kappaB enhancer, possibly contributing to HIV-1 transmission.
Adult↗
Immunologic responses associated with 12 weeks of combination antiretroviral therapy consisting of zidovudine, lamivudine, and ritonavir: results of AIDS Clinical Trials Group Protocol 315.
Human immunodeficiency virus (HIV)-1 infection is associated with progressive cell-mediated immune deficiency and abnormal immune activation. Although highly active antiretroviral therapy regimens can increase circulating CD4 T lymphocyte counts and decrease the risk of opportunistic complications, the effects of these treatments on immune reconstitution are not well understood. In 44 persons with moderately advanced HIV-1 infection, after 12 weeks of treatment with zidovudine, lamivudine, and ritonavir, plasma HIV-1 RNA fell a median of 2.3 logs (P < .0001). Circulating numbers of naive and memory CD4 T lymphocytes (P < .001), naive CD8 T lymphocytes (P < .004), and B lymphocytes (P < .001) increased. Improved lymphocyte proliferation to certain antigens and a tendency to improvement in delayed-type hypersensitivity also were seen. Dysregulated immune activation was partially corrected by this regimen; however, the perturbed expression of T cell receptor V regions in the CD4 and CD8 T lymphocyte populations was not significantly affected. Ongoing studies will ascertain if longer durations of virus suppression will permit more complete immune restoration.
Adult↗
Flow cytometric determination of ganciclovir susceptibilities of human cytomegalovirus clinical isolates.
A flow cytometric assay has been developed for the measurement of susceptibilities to ganciclovir of laboratory strains and clinical isolates of human cytomegalovirus (HCMV). The assay uses fluorochrome-labeled monoclonal antibodies to HCMV immediate-early and late antigens to identify HCMV-infected cells and flow cytometry to detect and quantitate the number of antigen-positive cells. By this assay, the 50 and 90% inhibitory concentrations (IC50 and IC90, respectively) of ganciclovir for the AD169 strain of HCMV were 1.7 and 9.2 microM, respectively, and the IC50 for the ganciclovir-resistant D6/3/1 derivative of the AD169 strain was greater than 12 microM. The ganciclovir susceptibilities of 17 HCMV clinical isolates were also determined by flow cytometric analysis of the effect of ganciclovir on late-antigen synthesis in HCMV-infected cells. The average IC50 of ganciclovir for drug-sensitive HCMV clinical isolates was 3.79 microM (+/-2.60). The plaque-reduction assay for these clinical isolates yielded an average IC50 of 2.80 microM (+/-1.46). Comparison of the results of the flow cytometry assays with those obtained from the plaque-reduction assays demonstrated acceptable bias and precision. Flow cytometric and plaque-reduction analysis of cells infected with ganciclovir-resistant clinical isolates failed to show a reduction in the percentage of late-antigen-positive cells or PFU, even at 96 microM ganciclovir. The flow cytometric assay for determining ganciclovir susceptibility of HCMV is quantitative, and objective, and potentially automatable, and its results are reproducible among laboratories.
Antigens, Viral↗
Costimulation of naive CD8(+) lymphocytes induces CD4 expression and allows human immunodeficiency virus type 1 infection.
Human immunodeficiency virus type 1 (HIV-1) infection requires cell surface expression of CD4. Costimulation of CD8(+)/CD4(-) T lymphocytes by anti-CD3 and anti-CD28 antibodies or by allogeneic dendritic cells induced expression of CD4 and rendered these CD8 cells susceptible to HIV-1 infection. Naive CD45RA+ cells responded with greater expression of CD4 than did CD45RO+ cells. CD8(+) lymphocytes derived from fetal or newborn sources exhibited a greater tendency to express CD4, consistent with their naive states. This mechanism of infection suggests HIV-induced perturbation of the CD8 arm of the immune response and could explain the generally rapid disease progression seen in HIV-infected children.
Adult↗
Lymphocyte phenotyping in infants: maturation of lymphocyte subpopulations and the effects of HIV infection.
Changes in the distribution of lymphocyte subpopulations in infants with perinatally acquired HIV infection are confounded by the rapid changes that are the result of normal maturation of the immune system. We describe the changes in seven lymphocyte phenotypes (CD3+ CD4+, CD3+ CD8+, CD8+ HLA- DR+, CD8+ CD38+, CD8+ CD57+, CD3-/ CD16+ 56+, and CD19+) over the first 2 years of life in 390 HIV-1 exposed but uninfected and 98 HIV-1-infected infants enrolled in the Women and Infants Transmission Study. The greatest changes in uninfected infants were declines in the CD3+ CD4+ lymphocytes and increases in CD8+ HLA- DR+ and CD19+ lymphocytes. All phenotypes were affected by HIV infection but the greatest changes were declines in the CD3+ CD4+ subset and increases in the CD3+ CD8+ and CD8+ HLA- DR+ subsets. Thus, this study provides reference data for the maturational changes in lymphocyte phenotypes in HIV-exposed but uninfected infants and describes the overall changes that occur with perinatally acquired HIV infection.
Adult↗
Changes in total, CD4+, and CD8+ lymphocytes during pregnancy and 1 year postpartum in human immunodeficiency virus-infected women. The Women and Infants Transmission Study.
OBJECTIVE: To assess changes in lymphocyte subsets during pregnancy and 1 year postpartum in human immunodeficiency virus (HIV)-infected women. METHODS: Changes in CD4+ and CD8+ cell counts, CD4 and CD8 percent, CD4/CD8 ratio, and total lymphocyte count and percent were assessed in each of 226 HIV-infected women followed during pregnancy and 1 year postpartum, and for each of 100 nonpregnant HIV-infected woman during 1 year. Trends over time were compared between pregnant women with and without several covariates. Postpartum changes over a 1-year period were compared to a 1-year period in the nonpregnant cohort. RESULTS: There was a mean increase of 2.76 per week in the CD4+ cell count during pregnancy (P = .04). No other characteristics changed significantly during pregnancy. The mean CD4+ and CD8+ cell counts, the CD8 percent, and the total lymphocyte count and percent increased immediately postdelivery. During the first postpartum year, there were statistically significant declines in the absolute CD4+ and CD8+ cell counts, the relative CD4 and CD8 percentages, and the total lymphocyte count and percentage. The rate of change for CD4+ and CD8+ counts, but not for CD4 percent, was less during 1 year in the nonpregnant cohort than in the first postpartum year, and the CD8 percent increased in the nonpregnant women. A wide variability in trends of all measurements during pregnancy was seen. CONCLUSION: During pregnancy, CD4 and CD8 percentages remain stable. There are no clinically significant changes during pregnancy or postpartum in any lymphocyte parameter we assessed. Postpartum changes in lymphocytes and lymphocyte subsets most likely represent a return to baseline from the physiologic changes of pregnancy and the immediate postpartum period.
Adult↗
Inhibition of cytokine-driven human immunodeficiency virus type 1 replication by protease inhibitor.
Protease inhibitors block virus maturation and prevent the spread of human immunodeficiency virus (HIV)-1 in vitro. HIV-1-positive persons produce higher levels of proinflammatory cytokines that up-regulate HIV-1 replication. For the protease inhibitor to be effective in vivo, it must be able to suppress cytokine-induced HIV-1 replication. The in vitro efficacy of protease inhibitor to block tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-1alpha, and IL-1beta induction of HIV-1 was investigated. While 100 U/mL of the respective cytokines induced a 208- to 22-fold increase in HIV-1 p24 production, addition of protease inhibitor completely inhibited this virus induction. The kinetics indicated a sustained HIV-1 inhibition despite high levels of endogenous TNF-alpha induction. Dilution of protease inhibitor led to increased HIV-1 replication. These results show that while protease inhibitor can prevent cytokine induction of HIV-1 replication, a continual effective dose is required for the inhibition to be sustained.
Cytokines↗
An approach to the validation of markers for use in AIDS clinical trials.
Dr. Mildvan and coauthors have thoroughly reviewed and documented what is known about the validation of surrogate markers for use in clinical trials. They have proposed a classification system based on the usefulness of available immunologic and virological assays as measures of prognosis, drug activity, and therapeutic efficacy. The latter, a type II marker in the proposed classification, should estimate the proportion of treatment effect explained by change in the marker induced by therapy and, if complete, can substitute for clinical endpoints. HIV clinical trialists have had a long-standing interest in using surrogates for clinical endpoints to facilitate conduct of experimental protocols and to decrease the time and effort required to develop new treatment strategies. The approach outlined in this review by experienced clinicians, biostatisticians, and immunologists provides a framework to evaluate currently available and potential surrogate markers.
Acquired Immunodeficiency Syndrome↗