HIV-1 DNA proviral load in treated and untreated HIV-1 sero-positive patients

As proviral human immunodeficiency virus type 1 (HIV-1) DNA can replenish and revive viral infection upon activation, its detection might offer significant therapeutic information, complementing the input provided by plasma RNA determination in the follow-up of infected individuals. A selected group of acutely infected subjects was studied to verify both total and 2-long terminal repeat (2-LTR) DNA proviral load during the acute phase of infection and thereafter. Patients were divided in two sex- and age-matched groups: 19 naive individuals who did not receive antiretroviral therapy during the observation period and 20 subjects treated according to current guidelines. Total and 2-LTR HIV-1 DNA proviral load, in addition to RNA viral load and CD4 cell count, were determined in peripheral blood mononuclear cells (PBMC) at baseline, 6 and 12 months after the first sampling. Total and 2-LTR HIV-1 DNA proviral load exhibited no significant variation at any time in the naive patients (total HIV-1 DNA ranging from 896 ± 731 to 715 ± 673 copies/10⁵ PBMC and 2-LTR HIV-1 DNA ranging from 94 ± 105 to 65 ± 44 copies/10⁵ PBMC), whereas a significant reduction in both total HIV-1 DNA (ranging from 997 ± 676 to 262 ± 174 copies/10⁵ PBMC) and 2-LTR HIV-1 DNA proviral load (ranging from 116 ± 55 to 26 ± 35 copies/10⁵ PBMC) was detected in highly active antiretroviral therapy (HAART) patients, together with a CD4⁺ T cell count increase and RNA load decrease. HAART negatively affects both the labile HIV burden and the integrated proviral DNA, at least in the initial period of successful treatment, suggesting that quantification of HIV-1 DNA proviral load may be an important parameter in monitoring HIV infection.     

Association of CD4+ T-lymphocyte counts and new thymic emigrants in HIV-infected children during successful highly active antiretroviral therapy

BACKGROUND: In a cohort of children receiving highly active antiretroviral therapy (HAART) with sustained plasma HIV-1 RNA < 50 copies/mL, children who reached undetectable RNA after week 8 (slow responders, median: week 20) had higher HIV-1 intracellular DNA (HIV-1 DNA) and equal or greater CD4+ T-lymphocyte counts compared with children who reached undetectable plasma HIV-1 RNA by week 8 (rapid responders) throughout HAART. OBJECTIVE: To determine whether levels of T-cell receptor excision circles (TRECs) could explain the apparent inconsistency between the quantity of HIV-1 DNA and CD4+ T-lymphocyte counts in HIV-1-infected children receiving HAART with sustained virologic suppression. METHODS: T-cell receptor excision circles and HIV-1 DNA and plasma HIV-1 RNA were quantified longitudinally by PCR in 31 children (median age, 5.6 years) with sustained undetectable plasma HIV-1 RNA for >104 weeks of HAART. RESULTS: There was a positive correlation between TREC and HIV-1 DNA during HAART, notably at weeks 48 and 80 (P < .004). During the early stage of HAART, TREC levels positively correlated with CD4+ T-lymphocyte percentages (P < .02) and naive CD4+ T-lymphocyte counts (P < .001) and percentages (P = .05). Median TREC levels were consistently equal or higher in slow responders compared with rapid responders (P < .001) despite slow responders having consistently greater quantities of HIV-1 DNA. CONCLUSION: To maintain adequate levels of CD4+ T-lymphocytes, children with high HIV-1 DNA maintain high levels of TREC while receiving HAART. Thus, a thymic control mechanism is required to maintain new CD4+ T lymphocytes in the presence of persistent virus. CLINICAL IMPLICATIONS: The TREC level is a useful marker of thymic function in HIV-infected children.     

Changes in CD4+ T-cell differentiation phenotype during structured treatment interruption in patients with chronic HIV-1 infection

Markers of maturation and activation were measured on peripheral CD4+ T cells in chronically HIV-1-infected patients in a randomized, controlled pilot study of structured treatment interruption (STI). Eight subjects underwent 2 cycles of 1 month off and 1 month on highly active antiretroviral therapy (HAART), followed by a final 3-month interruption. During STI, CD4+ T-cell percentage remained relatively stable in 4 of 8 subjects. The remaining 4 STI subjects had significant rapid decline in CD4+ T-cell percentage during STI, followed by return to pre-STI baseline while on HAART. Changes in overall CD4+ T-cell percentage corresponded with fluctuations in the CD45RA+CCR7+ naive and CD45RA-CCR7+ central memory subsets. Subjects with variable CD4+ T-cell percentages tended to have higher pre-HAART plasma HIV-1 RNA set-points and experienced higher levels of plasma HIV-1 RNA rebound during STI. These results suggest that interruptions should be avoided whenever possible in patients on HAART with high plasma HIV-1 RNA set-points.     

CD4 T cell recovery is slower in patients experiencing viral load rebounds during HAART.

To determine whether viral load rebounds during HAART impact on CD4+ T cell recovery and immune reconstitution, we studied a prospective cohort of 355 antiretroviral naive patients enrolled to be randomized in a trial of three strategies of induction/maintenance HAART. The extent of immune reconstitution in blood through 72 weeks of antiretroviral treatment was evaluated. Lymphocyte subset markers (CD4, CD8, CD45RA, CD62L, CD16, CD19), activation markers (HLA-DR, CD38, CD25) were performed by cytometry analysis. Our results showed that plasma HIV-1 RNA was suppressed to below 500 copies per ml through week 72 in 240 patients (group 1) while the remaining 115 patients experienced at least one viral rebound (group 2). At baseline, CD4 cell count was higher and HIV-1 RNA was lower in group 1 than in group 2. Over 72 weeks, mean increase in CD4+ T cell count was 0.32 cell/mm3/day in group 1 and only 0.14 cell/mm3/day in group 2 (P < 0.0001). However, the patterns of changes in CD4+ and CD8+ T cell subsets during therapy were very similar across the two groups with only subtle and very limited differences. We conclude that permanent control of HIV replication could be necessary for faster immune reconstitution.     

Decreases in plasma TNF-alpha level and IFN-gamma mRNA level in peripheral blood mononuclear cells (PBMC) and an increase in IL-2 mRNA level in PBMC are associated with effective highly active antiretroviral therapy in HIV-infected patients

In this study, we investigated the cytokine profiles of 14 treatment-naive HIV-infected patients on the initiation of highly active antiretroviral therapy (HAART). At baseline, plasma levels of TNF-alpha and its mRNA in peripheral blood mononuclear cells (PBMC) were highest in the most severely immunocompromised patients (<200 CD4+ cells/mm3). After 12 months of HAART, the virus was undetectable in the plasma of all patients (<200 copies/ml), and median CD4 T cell counts had increased (+164 cells/mm3). We also observed a gradual decrease in the number of proviral DNA copies in PBMC and in immune activation, with lower levels of IFN-gamma mRNA in PBMC associated with weaker activation of CD8+ T cells and lower levels of plasma TNF-alpha. IL-2 mRNA levels in PBMC were found to increase in parallel. The decrease in TNF-alpha and IFN-gamma levels and the increase in IL-2 production appear to be correlated with the efficacy of HAART in naive immunocompromised HIV-infected individuals.     

Quantifying residual HIV-1 replication in patients receiving combination antiretroviral therapy.

BACKGROUND: In patients infected with human immunodeficiency virus type 1 (HIV-1), combination antiretroviral therapy can result in sustained suppression of plasma levels of the virus. However, replication-competent virus can still be recovered from latently infected resting memory CD4 lymphocytes; this finding raises serious doubts about whether antiviral treatment can eradicate HIV-1. METHODS: We looked for evidence of residual HIV-1 replication in eight patients who began treatment soon after infection and in whom plasma levels of HIV-1 RNA were undetectable after two to three years of antiretroviral therapy. We examined whether there had been changes over time in HIV-1 proviral sequences in peripheral-blood mononuclear cells, which would indicate residual viral replication. We also performed in situ hybridization studies on tissues from one patient to identify cells actively expressing HIV-1 RNA. We estimated the rate of decrease of latent, replication-competent HIV-1 in resting CD4 lymphocytes on the basis of the decrease in the numbers of proviral sequences identified during primary infection and direct sequential measurements of the size of the latent reservoir. RESULTS: Six of the eight patients had no significant variations in proviral sequences during treatment. However, in two patients there was sequence evolution but no evidence of drug-resistant viral genotypes. In one patient, extensive in situ studies provided additional evidence of persistent viral replication in lymphoid tissues. Using two independent approaches, we estimated that the half-life of the latent, replication-competent virus in resting CD4 lymphocytes was approximately six months. CONCLUSIONS: These findings suggest that combination antiretroviral regimens suppress HIV-1 replication in some but not all patients. Given the half-life of latently infected CD4 lymphocytes of about six months, it may require many years of effective antiretroviral treatment to eliminate this reservoir of HIV-1.     

HIV-1 RNA被有效抑制下T细胞与外周血中HIV-1前病毒DNA

目的:考察HIV-1 RNA被有效抑制下T细胞与外周血中HIV-1前病毒DNA的相关性。方法:对云南地区90例确诊为AIDS,HAART持续治疗时间超过6个月,血浆HIV RNA<50 Copies/ml的患者进行研究,采用Spearmans秩和相关回顾性分析CD4+、CD3+、CD8+、CD4+CD28+、CD4+CD45RA+、CD4+CD45RO+、CD38+、CD8+CD38+T细胞的绝对计数和相对计数与外周血中HIV-1前病毒DNA的相关性,同时考察HIV-1前病毒DNA拷贝数与HAART持续治疗时间的相关性。将90例患者根据HAART后CD4+T细胞绝对计数分为A(CD4+<200 cells/μl)、B(200≤CD4+≤349 cells/μl)、C(CD4+≥350 cells/μl)3组,考察3组间T细胞亚群的差别。结果:HIV-1前病毒DNA的log拷贝数与CD4+CD45RA+T细胞绝对计数呈负相关(r=-0.231,P<0.05),与CD4+CD45RA+T细胞相对计数呈明显负相关(r=-0.270,P<0.01);与CD38+T细胞绝对计数呈正相关(r=0.250,P<0.05);与HAART持续治疗时间无相关性。B、C组的CD3+T细胞绝对计数明显高于A组(P<0.01);C组的CD8+T细胞绝对计数高于B组的(P<0.05);B、C组的CD4+CD28+T细胞绝对计数和相对计数明显高于A组(P<0.01),C组的CD4+CD28+T细胞绝对计数高于B组(P<0.05);B、C组的CD4+CD45RA+T细胞、CD4+CD45RO+T细胞绝对计数明显高于A组(P<0.01),C组的CD4+CD45RA+T细胞、CD4+CD45RO+T细胞绝对计数高于B组(P<0.05),B、C组的CD4+CD45RO+T细胞相对计数高于A组(P<0.05);B、C组的CD8+CD38+T细胞绝对计数低于A组(P<0.05),B组的CD8+CD38+T细胞相对计数低于A组(P<0.05);C组的CD38+T细胞绝对计数高于A组(P<0.05)。A、B、C组的HIV-1前病毒DNA的log拷贝数分别为3.561±0.297 9,3.605±0.277 6,3.434±0.289 1(copies/ml),3组间无显著性差异(P>0.05)。结论:经过HAART治疗后HIV-1前病毒DNA可能处于稳定状态,HIV-1前病毒DNA拷贝数只是某些T细胞亚群数量改变的原因之一。     

Quantification of human immunodeficiency virus type 1 proviral load by a TaqMan real-time PCR assay

Proviral human immunodeficiency virus type 1 (HIV-1) DNA could be a useful marker for exploring viral reservoirs and monitoring antiretroviral treatment, particularly when HIV-1 RNA is undetectable in plasma. A new technique was developed to quantify proviral HIV-1 using a TaqMan real-time PCR assay. One copy of proviral HIV-1 DNA could be detected with 100% sensitivity for five copies and the assay had a range of 6 log(10). Reproducibility was evaluated in intra- and interassays using independent extractions of the 8E5 cell line harboring the HIV-1 proviral genome (coefficients of variation [CV], 13 and 27%, respectively) and peripheral blood mononuclear cells (PBMC) from a patient with a mean proviral load of 26 copies per 10(6) PBMC (CV, 46 and 56%, respectively). The median PBMC proviral load of 21 patients, measured in a cross-sectional study, was determined to be 215 copies per 10(6) PBMC (range, <10 to 8,381). In a longitudinal study, the proviral load of 15 out of 16 patients with primary infection fell significantly during 1 year of antiretroviral therapy (P = 0.004). In the remaining patient, proviral HIV-1 DNA was detectable but not quantifiable due to a point mutation at the 5' end of the TaqMan probe. No correlation was observed between proviral load and levels of CD4(+) cells or HIV-1 RNA in plasma. TaqMan PCR is sensitive and adaptable to a large series of samples. The full interest of monitoring proviral HIV-1 DNA can now be ascertained by its application to the routine monitoring of patients.     

Virologic and immunologic response to highly active antiretroviral therapy in indigenous and nonindigenous HIV-1-infected patients in the Netherlands

OBJECTIVE: To compare the results of antiretroviral treatment (highly active antiretroviral therapy [HAART]) in indigenous Dutch (ID) and nonindigenous HIV-1-infected patients in Amsterdam, the Netherlands. We focused on the largest groups of nonindigenous people visiting our outpatient clinic: patients from other industrialized countries (western), from Surinam/Netherlands Antilles (SNA), and from sub-Saharan Africa (SSA). DESIGN: Retrospective cohort analysis of 692 therapy-naive HIV-1-positive individuals who visited our outpatient clinic for the first time between July 1, 1996 and December 31, 2001. METHODS: We compared the groups at the time of their first visit to our clinic; at the start of HAART; and according to the virological, immunologic, and clinical treatment response during the 96 weeks after the start of HAART. RESULTS: Of the patients starting antiretroviral therapy, 362 were ID, 84 were western, 72 were from SNA, and 110 were from SSA. SNA and SSA patients had a lower CD4 cell count at first visit (ID = 330 cells/mm(3), western = 330 cells/mm(3), SNA = 250 cells/mm(3), and SSA = 170 cells/mm(3); P = 0.0002). Treatment in SNA and SSA patients was also started at a lower CD4 cell count, but the plasma HIV-1 RNA level was comparable. After the start of HAART, a similar rise in CD4 cell count was seen in the 4 groups (P = 0.33), but the baseline difference in CD4 cell count remained present during the follow-up period of 96 weeks. After adjusting for variables potentially influencing treatment outcome, the proportion of patients not reaching a plasma HIV-1 RNA level <400 copies/mL was not different for the 4 groups in contrast to the percentage not reaching a plasma HIV-1 RNA level <50 copies/mL (at 48 weeks: ID = 4.8%, western = 27.5%, SNA = 23.1%, and SSA = 24.2%; P = 0.017 over the 96-week time period). After the start of HAART, nonindigenous patients also more often had progression to Centers for Disease Control and Prevention (CDC) stage C or died (P = 0.006). CONCLUSIONS: In nonindigenous patients, treatment with HAART was equally successful in terms of the increase in CD4 cell count but was substantially less effective in achieving a plasma HIV-1 RNA level below 50 copies/mL. Further investigations should explore differences in adherence and pharmacokinetics in these patient groups.     

IL-2 and IL-10 serum levels in HIV-1-infected patients with or without active antiretroviral therapy

We analyzed IL-2 and IL-10 serum levels in 26 HIV-1-infected patients naive of antiretroviral treatment and in 34 patients receiving highly active antiretroviral therapy (HAART). All patients without treatment were asymptomatic. When they were stratified according to levels of CD4+ T cells, IL-2 levels were significantly increased in patients with > or =200 CD4+/microl and IL-10 levels were significantly increased in patients with <200 CD4+/microl compared to controls. A significant negative correlation was observed between IL10 levels and CD4+ T-cell counts. No correlation was observed between IL-2 and IL-10 levels and viral load due to the wide range of variability in the number of HIV copies/ml present in the different patients. However, IL-2 levels were higher in patients with high viral load than in patients with low viral load. In patients with HAART, IL-2 and IL-10 levels were similar to the control group and no differences were detected respecting CD4+ T cells counts and viral load. Our findings show that the modifications in IL-2 and IL-10 serum levels in HIV-1-infected patients naive of antiretroviral treatment are associated with the progression of immunological damage. Furthermore, they show a dysbalance of type-1/type-2 cytokines with an involvement of type-2 cytokines in later stages of HIV infection. Cytokine dysregulation can be reversed by HAART in the context of immune restoration and viral suppression.     

Quantitative DNA proviral detection in HIV-1 patients treated with antiretroviral therapy.

The amount of proviral DNA in peripheral blood mononuclear cells (PBMCs) from 93 HIV-1 seropositive patients on long-lasting antiretroviral therapy was measured by the SYBR green real-time PCR technique. Variable levels of proviral DNA, ranging from 14 to 1847 copies of HIV-1 DNA per 10(6) PBMC were found, without a significant correlation between proviral load and plasma HIV-1 RNA levels or CD4(+) lymphocyte counts. To investigate the possible role of HIV-1 DNA levels as prognostic markers in clinical practice, the amount of proviral DNA and peripheral blood CD4(+) lymphocyte counts were further evaluated after 5 months of continued therapy in 32 patients who maintained a persistently undetectable viremia throughout the observation period. Interestingly, a clear-cut decrease (> or =0.5 log) in proviral DNA levels was significantly associated with a definite increase in CD4(+) lymphocyte counts. Even though plasma HIV-1 RNA levels remain the basic parameter to monitor both the intensity of viral replication and the efficacy of therapeutic interventions, the results obtained in our study seem to indicate that measuring proviral DNA levels could represent an adjunct prognostic marker, especially useful in patients whose HIV-1 RNA levels drop below detectable limits.     

T cell responses to highly active antiretroviral therapy defined by chemokine receptors expression, cytokine production, T cell receptor repertoire and anti-HIV T-lymphocyte activity

The immunological correlates of highly active antiretroviral therapy (HAART)-induced suppression of human immunodeficiency virus type 1 (HIV-1) replication have been investigated. 20 HIV-1-infected patients with mean CD4+ T cell count of 298/microl, plasma viral load of 4.7 log10 copies/ml and naive for protease inhibitors (PI) were studied during12 months of HAART. An increased number of both CD4+ and CD8+ naive T cells and a normalization of the frequency of CCR5- and CXCR4-expressing CD4+ T cells were readily observed after starting therapy. Single cell analysis of cytokine production after 12 months of HAART showed an increased number of interleukin (IL)-2-, but not IL-4- and (IFN)-gamma-, producing T cells and a decreased percentage of CD8+ IFN-gamma + cells. A correlation between the frequency of IFN-gamma-producing T cells and that of memory, CCR5+ and CD95+ T cells was demonstrated in both CD4+ and CD8+ subsets. The diversity of T cell receptor (TCR) variable beta (BV) chain repertoire significantly increased after 12 months of HAART within the CD4+ but not the CD8+ T cell subset. However, the level of perturbation of the third complementarity-determining region (CDR3), was not significantly modified by effective therapy. The number of anti-HIV Gag and Pol cytotoxic T lymphocytes precursors (CTLp) decreased during HAART and highly correlated with the CD8 IFN-gamma response. Ameliorated clinical conditions were observed in all patients in absence of any opportunistic infections during all the study period. These observations indicate that a better restoration of immunity may be obtained in patients starting HAART at less advanced stages of the disease.     

Plasma levels of soluble CD27: a simple marker to monitor immune activation during potent antiretroviral therapy in HIV-1-infected subjects

Plasma levels of soluble CD27 (sCD27) are elevated in diseases characterized by T cell activation and are used as a marker of immune activation. We assessed the usefulness of determining plasma sCD27 as a marker for monitoring immune activation in HIV-1-infected patients treated with highly active antiretroviral therapy (HAART). A first cross-sectional examination of 68 HIV-1-infected and 18 normal subjects showed high levels of sCD27 in HIV-1 infection; plasma sCD27 was correlated to HIV-1 viraemia and inversely correlated to CD4+ T cell count. Twenty-six HIV-1-infected patients undergoing HAART were studied at baseline and after 6, 12, 18 and 24 months of therapy. Seven additional patients under HAART were analysed at baseline, during and after interruption of therapy. In the total population, HAART induced a significant and progressive reduction, but not a normalization, of plasma levels of sCD27 after 24 months. A full normalization of plasma sCD27 was observed in the virological responders (undetectable HIV-1 RNA at months 18 and 24) and also in patients with moderate immunodeficiency at baseline (CD4+ T cell count >200 cells/mm3). Changes in plasma neopterin paralleled the changes in sCD27 but only baseline sCD27 levels were predictive of a greater increase in CD4+ T cell count during the follow-up. Discontinuation of therapy resulted in a rapid increase of sCD27 plasma levels associated with viraemia rebound and drop in CD4+ T cell count. Our findings suggest that plasma sCD27 may represent an alternative and simple marker to monitor immune activation during potent antiretroviral therapy. HIV-1-induced immune activation can be normalized by HAART in successfully treated patients where the disease is not advanced.     

Interleukin-15 production by monocyte-derived dendritic cells and T cell proliferation in HIV-infected patients with discordant response to highly active antiretroviral therapy

A discordant response to highly active antiretroviral therapy (HAART) occurs when CD4 T cell counts are stable or increased over time despite persistently detectable HIV-RNA levels. In order to identify immunological factors affecting discordant treatment responses, a total of 27 HIV-infected patients were studied: (a) 10 naive patients (mean CD4+ = 101.5 cells/microl; mean HIV-RNA = 4.8 log10 copies/ml); (b) seven responder patients (mean CD4+ = 908.9 cells/microl); and (c) 10 discordant patients (mean CD4+ = 396.1 cells/microl; mean HIV-RNA = 5.4 log10 copies/ml). Five healthy blood donors were included as HIV-seronegative controls. The following parameters were evaluated: interleukin (IL)-15 production by monocyte-derived dendritic cells (MDDC) after stimulation with lypopolysaccaride (LPS) and Candida albicans; recall and HIV-1-specific antigen lymphocyte proliferation (LP). Increased levels of IL-15 production by MDDC after stimulation with LPS and C. albicans were found both in discordant patients and responder patients. Conversely, a strong reduction of IL-15 levels was observed in naive patients. Discordant patients developed positive LP responses to C. albicans and HIV-1 p24. LP in response to C. albicans and HIV-1 p24 was also positive in responder patients. Decreased LP response was found in naive patients. In conclusion, HIV-infected patients with discordant viro-immunological responses to HAART present increased levels of IL-15 production by MDDC and enhanced recall and HIV-1-specific antigen LP responses, suggesting an improvement in indices of immune function.     

HIV-1 DNA burden in peripheral blood CD4+ cells influences disease progression, antiretroviral efficacy, and CD4+ T-cell restoration.

Integration of human immunodeficiency virus type-1 (HIV-1) proviral DNA into host cell genomic DNA ensures viral persistence despite suppression of active replication. Because HIV RNA originates from integrated HIV DNA, HIV RNA and DNA loads should interrelate when suppression of viral replication is incomplete. In addition, the link between proviral DNA formation and generation of HIV-1 genetic diversity suggests that the ease with which HIV escapes immune or drug-based suppression should vary with proviral load. Thus, HIV proviral load should have unique prognostic significance independent of the highly labile plasma HIV RNA levels commonly used to monitor patient status. To test this possibility, we developed a simple standardized research assay estimating the proportion of CD4+ peripheral blood mononuclear cells (PBMC) carrying HIV-1 DNA and investigated associations between this parameter, plasma virus load, long-term efficacy of antiretroviral therapy and restoration of CD4+ T cells. Lower proportions of CD4+ PBMC carrying HIV-1 DNA were associated with lower peak plasma HIV RNA levels and with more favorable long-term responses to antiretroviral therapy. These results suggest that HIV proviral load affects both disease progression and responsiveness to antiretroviral therapy. Therefore, new anti-HIV therapies addressing the stable pool of HIV proviral DNA should be developed to improve long-term prospects for suppression of HIV replication.     

Reservoirs of HIV-1 in vivo: implications for antiretroviral therapy

The eradication of HIV-1 from infected individuals remains the ultimate goal of all anti-HIV therapeutics. Although highly active antiretroviral therapy (HAART) has led to a profound decrease in morbidity and mortality in infected people by suppressing HIV replication, the virus continues to evolve slowly during therapy even when patients achieve below detectable levels of HIV in plasma. HIV-1 persists in latently infected memory CD4+ T cells and there is minimal decay of HIV in this compartment despite prolonged HAART. Various other reservoirs and sanctuary sites harboring HIV are also established in vivo during antiretroviral therapy. Collectively these sites represent a major impediment to the eradication of HIV-1. This review presents a detailed overview of various reservoir sites in vivo, and discusses their impact on the success and failure of HAART for HIV patients. In addition, it addresses the effect of sub-optimal drug concentrations on reservoir establishment and outlines future therapeutic strategies to counteract these reservoirs and sanctuaries.     

Quantification of in vivo replicative capacity of HIV-1 in different compartments of infected cells

Based on a mathematical model, we analyze the dynamics of CD4+ cells, actively, latently, persistently, and defectively infected cells and plasma virus after initiation of antiretroviral therapy in 14 HIV-1-infected asymptomatic patients. By simultaneous fitting of our model to clinical data of plasma HIV-1 RNA, peripheral blood mononuclear cell (PBMC)-gag RNA, proviral DNA, and CD4+ cell counts, we estimate kinetic parameters to determine the basic reproductive rate (R0) of the virus in different infected cell compartments as a measure of the replicative capacity of the virus in vivo. We find that the basic reproductive rate is larger than 1 before treatment only in actively infected cells (mean R0(act) approximately 2.46) indicating that only in this compartment the virus can maintain an ongoing infection. In latently and persistently infected cells the basic reproductive rate is considerably smaller (R0(lat) approximately 0.03 and R0(pers) approximately 0.008, respectively) indicating that these compartments contribute little to the total basic reproductive rate and cannot maintain an ongoing infection in absence of actively infected cells.     

Quantitative detection of human immunodeficiency virus type 1 (HIV-1) proviral DNA in peripheral blood mononuclear cells by SYBR green real-time PCR technique.

BACKGROUND: The persistence of proviral human immunodeficiency virus type 1 (HIV-1) DNA reservoir represents one of the major drawbacks to the total eradication of HIV-1. The quantitative determination of proviral HIV-1 DNA load offers significant therapeutic information, especially when the HIV-1 RNA levels drop below the detectable limits during the highly active retroviral therapy (HAART) treatment. Moreover, the detection of HIV-1 proviral DNA is an important diagnostic marker in the evaluation of HIV-1 infection of newborns of HIV-1 seropositive women. OBJECTIVE: We evaluated a real-time PCR based on LightCycler technology revealed through SYBR green fluorochrome (SYBR green real-time PCR) to quantify the HIV-1 proviral DNA load in peripheral blood mononuclear cells (PBMC) of HIV-1 seropositive patients. STUDY DESIGN: Firstly, we assessed the SYBR green real-time quantitative PCR for HIV-1 proviral DNA load detection determining the specificity and sensitivity of the assay using the LightCycler system. Secondly, we tested the performance of our SYBR green real-time PCR on 50 HIV-1 seropositive patients under HAART and 20 blood donors. RESULTS/CONCLUSIONS: The results of this study showed that our SYBR green real-time PCR is able to detect five copies of the HIV-1 genome. Moreover, our method revealed HIV-1 proviral DNA in all the 50 HIV-1 seropositive patients ( 627 +/- 1068 HIV-1 proviral DNA copies per 10(6) PBMC, with a range of 30-6300 copies), whereas no positive signal was observed in any PBMC blood donors. Our SYBR green real-time PCR represents a sensitive and useful approach that could be applied both in HIV-1 proviral DNA reservoir determination and in HAART monitoring, particularly when the HIV-1 plasmatic RNA is undetectable.