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PubMed2006

Diminished selection for thymidine-analog mutations associated with the presence of M184V in Ethiopian children infected with HIV subtype C receiving lamivudine-containing therapy.

BACKGROUND: We retrospectively studied the effect of the lamivudine-induced reverse transcription mutation M184V on selection of thymidine analog mutations (TAMs) in HIV subtype C-infected children and on clinical outcome. METHODS: We genotyped 135 blood samples from 55 children. TAMs accumulation, viral load and clinical outcome were compared in children maintained on zidovudine/stavudine + lamivudine + protease inhibitor/nonnucleoside reverse transcriptase inhibitor (PI/NNRTI) despite loss of viral suppression and in children treated with, or switched to, other nucleoside reverse transcriptase inhibitors (NRTIs). Drug susceptibility and replication capacity of selected samples were measured. RESULTS: M184V developed in 18 of 22 of children who had received only zidovudine/stavudine + lamivudine + PI/NNRTI during a mean of 23.2 +/- 3.2 months versus in 3 of 14 children treated with other drugs and/or having multiple regimen changes (P = 0.001). TAMs appeared, respectively, in 2 of 22 versus 12 of 14 (P < 0.0001). The 2 groups did not differ significantly in baseline HIV-RNA or CD4 count, sampling time, and follow-up period. In M184V-containing samples, we found large reductions in susceptibility to lamivudine and emtricitabine but not to other NRTIs. When T215Y was present without M184V, susceptibility to zidovudine was reduced 8-fold. When both M184V + T215Y occurred, susceptibility to zidovudine was substantially increased. Average inhibition concentration 50 values were similar to those documented in the Stanford database for subtype B HIV with these mutation patterns. CONCLUSIONS: Maintaining a thymidine analog + lamivudine-based regimen reduced accumulation of TAMs and increased zidovudine susceptibility. This is likely the result of an increased susceptibility to thymidine analog (zidovudine) in the context of M184V documented here for the first time in subtype C-infected children. This retrospective study supports the strategy of maintaining lamivudine-containing therapy in subtype C-infected children. This strategy may be beneficially applied in the treatment of children in Africa, where thymidine analog + lamivudine-based regimen became available recently but further options are limited.

Anti-HIV Agents↗
PubMed2005

The Protease Inhibitor Transfer Study (PROTRA 1): abacavir and efavirenz in combination as a substitute for a protease inhibitor in heavily pretreated HIV-1-infected patients with undetectable plasma viral load.

OBJECTIVES: The aim of the study was to evaluate the safety and efficacy of abacavir (ABC) and efavirenz (EFV) instead of a protease inhibitor (PI) in HIV-1-infected subjects treated with two nucleoside reverse transcriptase inhibitors (NRTIs) and one PI with undetectable viral loads (< 50 HIV -1 RNA copies/mL). To be eligible for inclusion, patients had to have a history of viral load < 400 copies/mL for at least 3 months and had to be naive to treatment with nonnucleoside reverse transcriptase inhibitors (NNRTIs) and ABC, but multiple pretreatment and treatment failure were allowed. DESIGN: An open-label, single-centre pilot study of duration 48 weeks was conducted. ABC was added to the original treatment with two NRTIs and one PI at baseline, and at week 6 the PI was replaced by EFV. At each study visit, CD4 cell count, viral load [measured by polymerase chain reaction (PCR)] and clinical chemistry were measured. Fasting blood samples were taken at baseline and at weeks 12, 24, 36 and 48 to measure levels of cholesterol [high-density lipoprotein (HDL)/low-density lipoprotein (LDL)], triglycerides, insulin and C-peptide. Additionally, an oral glucose tolerance test (OGTT) was performed. A bioelectric impedance analysis (BIA) and a single slice abdominal and mid-thigh computed tomography (CT) scan were carried out to assess changes in body composition. RESULTS: Thirty patients were included in the study. Three patients experienced ABC-hypersensitivity and one patient demonstrated virological failure caused by nonadherence. At week 48, all remaining patients had viral loads < 50 copies/mL with stable CD4 counts. The fasting metabolic parameters and abdominal fat distribution remained unchanged. CONCLUSIONS: In heavily pretreated patients, ABC and EFV in combination provide an effective, simplified and well-tolerated alternative to PI treatment.

Adult↗
PubMed2006

Efavirenz/emtricitabine/tenofovir disoproxil fumarate: triple combination tablet.

A new formulation combining fixed doses of the nucleoside reverse transcriptase inhibitors emtricitabine (200mg) and tenofovir disoproxil fumarate (tenofovir DF; 300 mg) with the non-nucleoside reverse transcriptase inhibitor efavirenz (600 mg) represents the first once-daily, one-tablet antiretroviral regimen. Co-formulated efavirenz/emtricitabine/tenofovir DF demonstrated bioequivalence to concomitant administration of the individual agents in a pharmacokinetic trial in healthy volunteers (n = 48). Co-formulated efavirenz/emtricitabine/tenofovir DF has not been evaluated in clinical trials. However, a once-daily regimen of efavirenz, emtricitabine and tenofovir DF (administered as individual agents) was superior to once-daily efavirenz plus twice-daily co-formulated lamivudine/zidovudine in terms of virological suppression, immunological recovery and adverse events resulting in discontinuation of the study medications in a randomised, multicentre, noninferiority study in treatment-naive patients with HIV infection (n = 517). Both regimens are currently recommended as initial antiretroviral therapy. Preliminary data suggest that co-formulated efavirenz/emtricitabine/tenofovir DF, like the individual agents in combination with other antiretroviral drugs, is generally well tolerated. CNS adverse events, primarily headache and dizziness, were the most common treatment-emergent, drug-related adverse events in the pharmacokinetic study involving the co-formulation.

Adenine↗
PubMed2004

New Antiretroviral Agents for the Treatment of HIV Infection.

Issues, such as complexity, tolerability, and drug resistance and cross-resistance, limit the effectiveness of current antiretroviral regimens and make the continued development of newer agents important, despite the availability of 20 approved drugs for the treatment of HIV infection. Many new compounds are in development in existing classes: nucleoside and nucleotide analogue reverse transcriptase inhibitors (eg, D-d4FC and SPD754), non-nucleoside analogue reverse transcriptase inhibitors (eg, capravirine and TMC125), and protease inhibitors (eg, tipranavir and TMC114). In addition, newer classes of antiretroviral drugs, such as HIV entry inhibitors (eg, TNX-355, SCH 417690, UK-427,857, AMD 11070), that target the first step in the HIV life cycle are under development. Continued improvement in the treatment of HIV infection will result from the availability of convenient, well-tolerated, and affordable drugs with potent and durable antiretroviral activity.

Journal Article↗
PubMed2005

Prevalence of antiretroviral drug resistance mutations in chronically HIV-infected, treatment-naive patients: implications for routine resistance screening before initiation of antiretroviral therapy.

BACKGROUND: The prevalence of drug resistance among persons with newly acquired human immunodeficiency virus (HIV) infection is well documented. However, it is unclear to what extent these mutations persist in chronically infected, treatment-naive patients. METHODS: Prevalence of and factors associated with genotypic drug resistance were analyzed retrospectively in a subset of 491 chronically HIV-infected, antiretroviral-naive patients enrolled at 25 cities in the Terry Beirn Community Programs for Clinical Research on Acquired Immune Deficiency Syndrome (AIDS) Flexible Initial Retrovirus Suppressive Therapies trial during 1999-2001. Resistance was defined on the basis of the International AIDS Society 2003 definition, as well as the presence of additional mutations at codons 215 (C/D/E/S) and 69 (A/N/S) in the pol gene. Prevalence of mutations was estimated by use of techniques for stratified random samples. Logistic regression models were used to determine factors associated with resistance. RESULTS: Among the 491 chronically HIV-infected patients (mean CD4 cell count, 269 cells/mm(3); 31% of patients had a prior AIDS diagnosis), 57 (11.6%) had >or=1 resistance mutation, resulting in an estimated prevalence for the cohort of 10.8% (95% confidence interval [CI], 9.5%-12.1%). The prevalence was 8.8% if the 118I mutation was excluded. By drug class, the estimated prevalence of mutations conferring resistance to nucleoside reverse-transcriptase inhibitors was 7.8%, and the prevalence was 3.0% for nonnucleoside reverse-transcriptase inhibitors and 0.7% for protease inhibitors. In a multiple logistic regression analysis, non-Hispanic white subjects were twice as likely than African American subjects to have resistance (odds ratio [OR], 2.1; 95% CI, 1.1-4.1; P=.03), and there was a 40% increase per year in prevalence of mutations by later year of enrollment (OR, 1.4; 95% CI, 1.0-2.1; P=.05). CONCLUSIONS: These results demonstrate the persistence of drug resistance mutations in chronically HIV-infected patients and an increasing prevalence of resistance over time, and they support genotyping of virus at baseline for chronically HIV-infected patients.

Adult↗
PubMed1997

Antiretroviral therapies in HIV-1 infection.

Recent progress in our understanding of the viral dynamics and immunobiology of HIV infection, coupled with the introduction of a new generation of antiretroviral agents, has led to significant advances in the medical management of HIV infection. Eleven antiretroviral drugs are currently licensed in the United States, and eight are licensed in Europe. These include the nucleoside reverse transcriptase inhibitors (AZT, ddI, ddC, 3TC and d4T); the non-nucleoside reverse transcriptase inhibitors (nevirapine and delavirdine) and the protease inhibitors (saquinavir, indinavir and ritonavir). This report summarises recent developments in the use of antiretroviral therapies and the main treatment strategies under evaluation in current trials. These strategies include the evaluation of novel antiretroviral agents; combinations to achieve maximal viral suppression; optimal sequencing of antiretroviral agents; and subtraction therapy. However, many important issues in the use of antiretroviral therapies remain unresolved, including the optimal role of new agents, such as protease inhibitors (PIs), and the use of triple combination therapy in initial and subsequent treatment regimens; when therapy should be changed; which alternative agents should then be used; and the most appropriate methods for monitoring the efficacy of therapy.

Journal Article↗
PubMed1999

Effects of human immunodeficiency virus type 1 resistance to protease inhibitors on reverse transcriptase processing, activity, and drug sensitivity.

Human immunodeficiency virus type 1 (HIV-1) variants resistant to protease inhibitors often display a reduced replicative capacity as a result of an impairment of protease function. Such fitness-impaired viruses display Gag precursor maturation defects. Here, we report that some protease inhibitor-resistant viruses also display abnormalities in the processing of reverse transcriptase (RT) by the protease. In three recombinant viruses carrying resistant protease sequences from patient plasma, we observed a marked decrease in the amount of mature RT subunits and of particle-associated RT activity compared to their parental pretherapy counterparts. We investigated the possibility that a decrease in the amount of particle-associated mature RT could affect the sensitivity of the corresponding virus to RT inhibitors. We observed a twofold increase of sensitivity to zidovudine (AZT) when a virus which carried AZT mutations was processed by a resistant protease. Interestingly, the presence of AZT-resistance mutations partially rescued the replication defect associated with the mutated protease. The interplay between resistance to protease inhibitors and to RT inhibitors described here may be relevant to the therapeutic control of HIV-1 infection.

Anti-HIV Agents↗
PubMed2001

New developments in anti-HIV chemotherapy.

Virtually all the compounds that are currently used, or under advanced clinical trial, for the treatment of HIV infections, belong to one of the following classes: (i) nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs): i.e., zidovudine (AZT), didanosine (ddI), zalcitabine (ddC), stavudine (d4T), lamivudine (3TC), abacavir (ABC), emtricitabine [(-)FTC], tenofovir (PMPA) disoproxil fumarate; (ii) non-nucleoside reverse transcriptase inhibitors (NNRTIs): i.e., nevirapine, delavirdine, efavirenz, emivirine (MKC-442); and (iii) protease inhibitors (PIs): i.e., saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, and lopinavir. In addition to the reverse transcriptase and protease step, various other events in the HIV replicative cycle are potential targets for chemotherapeutic intervention: (i) viral adsorption, through binding to the viral envelope glycoprotein gp120 (polysulfates, polysulfonates, polyoxometalates, zintevir, negatively charged albumins, cosalane analogues); (ii) viral entry, through blockade of the viral coreceptors CXCR4 and CCR5 [bicyclams (i.e. AMD3100), polyphemusins (T22), TAK-779, MIP-1 alpha LD78 beta isoform]; (iii) virus-cell fusion, through binding to the viral glycoprotein gp41 [T-20 (DP-178), T-1249 (DP-107), siamycins, betulinic acid derivatives]; (iv) viral assembly and disassembly, through NCp7 zinc finger-targeted agents [2,2'-dithiobisbenzamides (DIBAs), azadicarbonamide (ADA) and NCp7 peptide mimics]; (v) proviral DNA integration, through integrase inhibitors such as L-chicoric acid and diketo acids (i.e. L-731,988); (vi) viral mRNA transcription, through inhibitors of the transcription (transactivation) process (fluoroquinolone K-12, Streptomyces product EM2487, temacrazine, CGP64222). Also, in recent years new NRTIs, NNRTIs and PIs have been developed that possess respectively improved metabolic characteristics (i.e. phosphoramidate and cyclosaligenyl pronucleotides of d4T), or increased activity against NNRTI-resistant HIV strains [second generation NNRTIs, such as capravirine and the novel quinoxaline, quinazolinone, phenylethylthiazolylthiourea (PETT) and emivirine (MKC-442) analogues], or, as in the case of PIs, a different, non-peptidic scaffold [i.e. cyclic urea (DMP 450), 4-hydroxy-2-pyrone (tipranavir)]. Given the multitude of molecular targets with which anti-HIV agents can interact, one should be cautious in extrapolating from cell-free enzymatic assays to the mode of action of these agents in intact cells. A number of compounds (i.e. zintevir and L-chicoric acid, on the one hand; and CGP64222 on the other hand) have recently been found to interact with virus-cell binding and viral entry in contrast to their proposed modes of action targeted at the integrase and transactivation process, respectively.

Amino Acid Sequence↗
PubMed2004

Symptomatic bone disorders in HIV-infected patients: incidence in the Aquitaine cohort (1999-2002).

BACKGROUND: Since the inception of highly active antiretroviral therapy (HAART), mortality among HIV-infected patients has decreased, but this has been accompanied by the appearance of several complications. OBJECTIVES: To estimate the incidence of symptomatic bone disorders in HIV-infected patients of the Aquitaine cohort (from south-west France) for the period 1999-2002, and to describe cases. METHODS: We retrospectively studied the records of 2700 patients of the Aquitaine cohort, which was derived from a hospital-based surveillance system of HIV infection in France. All cases of symptomatic bone disorders diagnosed from 1 January 1999 to 30 June 2002 were reviewed. RESULTS: Fourteen cases of bone disorders were diagnosed, eight cases of aseptic osteonecrosis and six cases of severe osteoporosis, representing incidences of 0.3/1000 patient-years [95% confidence interval (CI): 0.14-0.62] and 0.22/1000 patient-years (95% CI: 0.09-0.52), respectively. All patients with aseptic osteonecrosis were male, while all but one with osteoporosis were female. The ages of patients ranged from 36 to 54 years for osteonecrosis and from 39 to 50 for severe osteoporosis. At the time of clinical diagnosis, all patients were treated with nucleoside reverse transcriptase inhibitors (duration of treatment ranging from 19 to 123 months for osteonecrosis and from 46 to 132 months for severe osteoporosis). Ten patients were treated with nonnucleoside reverse transcriptase inhibitors [duration of treatment ranging from 6 to 31 months for osteonecrosis (n=6) and from 4 to 29 months for severe osteoporosis (n=4)]. Thirteen patients were treated with protease inhibitors [duration of treatment ranging from 12 to 62 months for osteonecrosis (n=8) and from 3 to 44 months for severe osteoporosis (n=5)]. All osteonecrosis and five osteoporosis patients had at least one known risk factor or comorbidity associated with the bone disorder occurrence. CONCLUSIONS: In our study, the aetiology of clinical bone disorders seemed to be multifactorial, as almost all the patients had at least one possible risk factor in addition to HAART exposure.

Adult↗
PubMed2005

Impact of drug resistance genotypes on CD4+ counts and plasma viremia in heavily antiretroviral-experienced HIV-infected patients.

The number of HIV-infected individuals with prior multiple treatment failures is increasing as time passes by. The success of antiretroviral therapy in these patients is often compromised by the selection of drug-resistant viruses. Despite initial concerns, a rebound in AIDS cases among heavily treatment-experienced patients failing virologically their antiretroviral therapy has not occurred yet. In a multicenter study conducted in Spain, HIV-infected patients were assessed with prior failure to antiretrovirals from the three main drug families who presented during the last semester of the year 2003 with plasma HIV-RNA values above 1,000 copies/ml, despite good treatment adherence. The relationships between CD4+ T cell counts, viral loads and drug-resistant genotypes were examined. A total of 273 patients were identified in 12 centers (78% male, median age: 41 years). The mean viral load was 50,438 copies/ml and the mean CD4+ count was 328 cells/mul. Only 19.5% had less than 200 CD4+ T cells/mul. Most patients (95%) were receiving nucleoside reverse transcriptase inhibitors (NRTI) in their last antiretroviral regimen, while 63% were treated with protease inhibitors (PI) and 27% on non-nucleoside reverse transcriptase inhibitors (NNRTI). Overall, 97.4% had at least one drug resistance mutation (87.2% for NRTI, 68.5% for NNRTI, and 92.7% for PI). Using the virtual phenotype, resistance to three or more drugs within each class was recognized in 45.8% for NRTI, 40.7% for NNRTI, and 44.7% for PI. Moreover, cross-resistance to compounds from two or three drug families was recognized in 41% and 19.4% of patients, respectively. Nearly half of the patients had plasma HIV-RNA below 10,000 copies/ml and they showed significantly higher CD4 + counts than those with greater viremia (408 versus 259 cells/mul; P < 0.001). Patients with higher plasma viremia had significantly more drug resistance mutations than those with lower viremia. No favorable effect on viral load could be recognized for individual drug resistance mutations known to reduce viral fitness in vitro (i.e., rtM184V, rtL74V, rtK65R, proD30N, or proI50L). In summary, a large proportion of treatment-experienced patients failing their current antiretroviral regimen carry viruses with broad cross-resistant genotypes. Nearly half of the patients with these multi-drug resistant viruses had < 10,000 HIV-RNA copies/ml and 80% have more than 200 CD4 + T cells/mul. Thus, maintaining treatment HIV-infected individuals failing virologically and harboring drug-resistant viruses might ameliorate immunological deterioration until new drugs became available. J. Med. Virol. 77:23-28, 2005. (c) 2005 Wiley-Liss, Inc.

Adult↗
PubMed2006

Emergence of drug resistance is associated with an increased risk of death among patients first starting HAART.

BACKGROUND: The impact of the emergence of drug-resistance mutations on mortality is not well characterized in antiretroviral-naïve patients first starting highly active antiretroviral therapy (HAART). Patients may be able to sustain immunologic function with resistant virus, and there is limited evidence that reduced sensitivity to antiretrovirals leads to rapid disease progression or death. We undertook the present analysis to characterize the determinants of mortality in a prospective cohort study with a median of nearly 5 y of follow-up. The objective of this study was to determine the impact of the emergence of drug-resistance mutations on survival among persons initiating HAART. METHODS AND FINDINGS: Participants were antiretroviral therapy naïve at entry and initiated triple combination antiretroviral therapy between August 1, 1996, and September 30, 1999. Marginal structural modeling was used to address potential confounding between time-dependent variables in the Cox proportional hazard regression models. In this analysis resistance to any class of drug was considered as a binary time-dependent exposure to the risk of death, controlling for the effect of other time-dependent confounders. We also considered each separate class of mutation as a binary time-dependent exposure, while controlling for the presence/absence of other mutations. A total of 207 deaths were identified among 1,138 participants over the follow-up period, with an all cause mortality rate of 18.2%. Among the 679 patients with HIV-drug-resistance genotyping done before initiating HAART, HIV-drug resistance to any class was observed in 53 (7.8%) of the patients. During follow-up, HIV-drug resistance to any class was observed in 302 (26.5%) participants. Emergence of any resistance was associated with mortality (hazard ratio: 1.75 [95% confidence interval: 1.27, 2.43]). When we considered each class of resistance separately, persons who exhibited resistance to non-nucleoside reverse transcriptase inhibitors had the highest risk: mortality rates were 3.02 times higher (95% confidence interval: 1.99, 4.57) for these patients than for those who did not exhibit this type of resistance. CONCLUSIONS: We demonstrated that emergence of resistance to non-nucleoside reverse transcriptase inhibitors was associated with a greater risk of subsequent death than was emergence of protease inhibitor resistance. Future research is needed to identify the particular subpopulations of men and women at greatest risk and to elucidate the impact of resistance over a longer follow-up period.

Adult↗
PubMed2006

The influence of natural substrates and inhibitors on the nucleotide-dependent excision activity of HIV-1 reverse transcriptase in the infected cell.

Human immunodeficiency virus type 1 resistance to nucleoside reverse transcriptase inhibitors such as 3'-azido-2', 3'-dideoxythymidine (AZT) can arise through mutations in the coding region of reverse transcriptase (RT) that enhance the enzyme's ability to remove the drug after it has been incorporated. This excision activity of HIV-1 RT has been well characterized in a number of in vitro systems. However, the in vitro findings do not provide a complete picture of the in vivo significance of this resistance mechanism. This review will attempt to bridge the gap between the in vitro observations and the in vivo environment by summarizing the fragmentary information that is available about the intracellular conditions that may influence drug excision in cell subpopulations that are infected by HIV-1. Topics that will be discussed include (a) intracellular compounds HIV-1 RT may use to remove chain terminators; (b) how dNTPs can affect excision activity and how these effects differ in different immune cell subpopulations; (c) the influence of HIV infection on excision activity--e.g., through immune activation of infected cells or through changes indirectly induced in cells that subsequently become infected; (d) intracellular conditions that favor selection for mutations that increase the excision-based resistance mechanism; (e) the importance of macrophages in the selection of resistance mutations. Understanding factors that control excision in the intracellular environment will greatly enhance our understanding of the process of selection for this class of drug resistance mutations and may open doors for the development of novel targets for antiviral therapy.

DNA Repair↗
PubMed2000

Resistance profiles in patients with viral rebound on potent antiretroviral therapy.

The prevalence of phenotypic drug resistance was assessed in 60 patients with a viral rebound after they received a protease inhibitor (PI)- or nonnucleoside reverse transcriptase inhibitor (NNRTI)-containing regimen (baseline). Resistance testing was done within 36 weeks of viral rebound; no resistance testing was available at baseline. All patients had previously received zidovudine; 86.0% had received lamivudine. In total, 45.1% of the patients had strains resistant to the PI that they started and 88.9% given nevirapine had strains with reduced susceptibility to that drug. Overall, 46 patients (76.7%) harbored a strain resistant to >/=1 drug of their initial PI- or NNRTI-containing regimen. Of 53 patients who remained on treatment at the time of the study (40 had switched to a different combination from that at baseline), 6 harbored isolates susceptible to all drugs they had ever received. Thus, patients with viral rebound while on potent antiretroviral therapy usually have reduced susceptibility to >/=1 drug. Viral rebound also occurs in persons in whom resistant strains could not be detected by the assay used.

Drug Resistance↗
PubMedDate not supplied

[Non-nucleoside antiretroviral agents].

Antiviral agents, other than nucleoside reverse transcriptase inhibitors, are currently being developed. Some have been marketed. Most of these new drugs are protease inhibitors which inhibit the formation and release of new infecting virions at the end of the intracellular cycle of the human immunodeficiency virus. Saquivanir, ritonavir, and indinavir are among the most widely studied. Non-nucleoside reverse transcriptase inhibitors (nevirapine is the leading product) include several components called TIBO or TIBO-like. These drugs have the advantage of good tolerance but resistance may develop early when they are given alone. Clinical trials aimed at preventing virus-cell fusion have not been successful in vivo. Other therapeutic approaches, including antisense oligonucleotids, ribozymes, and TAT or REV gene inhibitors are being explored. Several trials focusing on therapeutic strategy are being conducted using combinations of drugs. The objective is to use both non-nucleoside and nucleoside reverse transcriptase inhibitors together with antiproteases. Certain combination protocols using 3 or more antiviral agents have shown a synergetic effect and reduced or delayed resistance. Finally, the role of immunomodulation and immunotherapy is under investigation.

Animals↗
PubMed1998

Long-lasting recovery in CD4 T-cell function and viral-load reduction after highly active antiretroviral therapy in advanced HIV-1 disease.

BACKGROUND: Highly active antiretroviral therapy (HAART) decreases viral load and increases CD4 T-cell counts in patients with advanced HIV-1 infection. Whether HAART can improve CD4 T-cell function, and the biological characteristics affecting immune reconstitution, remain unclear. We undertook an open prospective pilot study to address these issues. Both treatment-naïve and previously treated patients were included. METHODS: 20 patients (seven naïve, 13 previously treated) were treated with one protease inhibitor and two reverse-transcriptase inhibitors and followed up for 12 months. We measured CD4-cell proliferation in response to cytomegalovirus and tuberculin antigens and counted subsets of CD4 cells at baseline and months 1, 3, 6, 9, and 12. Patients who had no antigen-specific reactivity at baseline but developed it while receiving HAART were classified as immunological responders. FINDINGS: Four patients had antigen-specific reactivity at baseline compared with 14 at month 12 (p <0.001). Between month 3 and month 12 viral load fell by a median of 1.5 log copies/mL from baseline (4.6 log copies/mL) and CD4-cell count increased by a median of 63/microL (from 93/microL). Ten patients (six of seven naïve, four of 13 previously treated) were immunological responders. They differed significantly from the ten non-responders in that their viral-load reduction was sustained for 12 months, the increase in CD4 count was greater, and they showed an early increase in memory CD4 T cells with an increase of naïve T cells. INTERPRETATION: HAART can induce sustained recovery of CD4 T-cell reactivity against opportunistic pathogens in severely immunosuppressed patients. This recovery depends not on baseline values but on the amplitude and duration of viral-load reduction and the increase of memory CD4 T cells.

Adult↗