Achieving the UNAIDS 90-90-90 targets: a comparative analysis of four large community randomised trials delivering universal testing and treatment to reduce HIV transmission in sub-Saharan Africa.

BACKGROUND: Four large community-randomized trials examining universal testing and treatment (UTT) to reduce HIV transmission were conducted between 2012-2018 in Botswana, Kenya, Uganda, Zambia and South Africa. In 2014, the UNAIDS 90-90-90 targets were adopted as a useful metric to monitor coverage. We systematically review the approaches used by the trials to measure intervention delivery, and estimate coverage against the 90-90-90 targets. We aim to provide in-depth understanding of the background contexts and complexities that affect estimation of population-level coverage related to the 90-90-90 targets. METHODS: Estimates were based predominantly on "process" data obtained during delivery of the interventions which included a combination of home-based and community-based services. Cascade coverage data included routine electronic health records, self-reported data, survey data, and active ascertainment of HIV viral load measurements in the field. RESULTS: The estimated total adult populations of trial intervention communities included in this study ranged from 4,290 (TasP) to 142,250 (Zambian PopART Arm-B). The estimated total numbers of PLHIV ranged from 1,283 (TasP) to 20,541 (Zambian PopART Arm-B). By the end of intervention delivery, the first-90 target (knowledge of HIV status among all PLHIV) was met by all the trials (89.2%-94.0%). Three of the four trials also achieved the second- and third-90 targets, and viral suppression in BCPP and SEARCH exceeded the UNAIDS target of 73%, while viral suppression in the Zambian PopART Arm-A and B communities was within a small margin (~ 3%) of the target. CONCLUSIONS: All four UTT trials aimed to implement wide-scale testing and treatment for HIV prevention at population level and showed substantial increases in testing and treatment for HIV in the intervention communities. This study has not uncovered any one estimation approach which is superior, rather that several approaches are available and researchers or policy makers seeking to measure coverage should reflect on background contexts and complexities that affect estimation of population-level coverage in their specific settings. All four trials surpassed UNAIDS targets for universal testing in their intervention communities ahead of the 2020 milestone. All but one of the trials also achieved the 90-90 targets for treatment and viral suppression. UTT is a realistic option to achieve 95-95-95 by 2030 and fast-track the end of the HIV epidemic.

The effect of an intervention to promote isoniazid preventive therapy on leadership and management abilities.

BACKGROUND: Across sub-Saharan Africa, mid-level healthcare managers oversee implementation of national guidelines. It remains unclear whether leadership and management training can improve population health outcomes. METHODS: We sought to evaluate leadership/management skills among district-level health managers in Uganda participating in the SEARCH-IPT randomised trial to promote isoniazid preventive therapy (IPT) for persons with HIV (PWH). The intervention, which led to higher IPT rates, included annual leadership/management training of managers. We conducted a cross-sectional survey assessing leadership/management skills among managers at trial completion. The survey evaluated self-reported use of leadership/management tools and general leadership/management. We conducted a survey among a sample of providers to understand the intervention's impact. Targeted minimum loss-based estimation (TMLE) was used to compare responses between trial arms. RESULTS: Of 163 managers participating in the SEARCH-IPT trial, 119 (73%) completed the survey. Intervention managers reported more frequent use of leadership/management tools taught in the intervention curriculum than control managers (+3.64, 95% CI 1.98-5.30, P < 0.001). There were no significant differences in self-reported leadership skills in the intervention as compared to the control group. Among providers, the average reported quality of guidance and supervision was significantly higher in intervention vs control districts (+1.08, 95% CI 0.63-1.53, P = 0.001). CONCLUSIONS: A leadership and management training intervention increased the use of leadership/management tools among mid-level managers and resulted in higher perceived quality of supervision among providers in intervention vs control districts in Uganda. These findings suggest improved leadership/management among managers contributed to increased IPT use among PWH in the intervention districts of the SEARCH-IPT trial.

CONTEXTE: Dans toute l'Afrique subsaharienne, les gestionnaires de soins de santé de niveau intermédiaire supervisent la mise en œuvre des directives nationales. Il n'est toujours pas clair si la formation en leadership et en gestion peut améliorer les résultats en matière de santé de la population. MÉTHODES: Nous avons cherché à évaluer les compétences en leadership et en gestion des responsables de la santé au niveau des districts en Ouganda participant à l'essai randomisé SEARCH-IPT visant à promouvoir le traitement préventif à l'isoniazide (TPI) pour les personnes vivant avec le VIH (PWH, pour l'anglais « people living with HIV ¼). L'intervention, qui a permis d'augmenter les taux de TPI, comprenait une formation annuelle en leadership et en gestion des gestionnaires. Nous avons mené une enquête transversale pour évaluer les compétences en leadership et en gestion des gestionnaires à la fin de l'essai. L'enquête a évalué l'utilisation autodéclarée d'outils de leadership et de gestion et de leadership et de gestion en général. Nous avons mené une enquête auprès d'un échantillon de prestataires pour comprendre l'impact de l'intervention. L'estimation ciblée basée sur les pertes minimales (TMLE, « Targeted minimum loss-based estimation ¼) a été utilisée pour comparer les réponses entre les groupes de l'essai. RÉSULTATS: Sur les 163 gestionnaires qui ont participé à l'essai SEARCH-IPT, 119 (73%) ont répondu au sondage. Les gestionnaires d'intervention ont déclaré utiliser plus fréquemment les outils de leadership/gestion enseignés dans le programme d'intervention que les gestionnaires de contrôle (+3,64 ; IC à 95% 1,98­5,30 ; P < 0,001). Il n'y avait pas de différences significatives dans les compétences de leadership autodéclarées dans l'intervention par rapport au groupe témoin. Parmi les prestataires, la qualité moyenne déclarée de l'orientation et de la supervision était significativement plus élevée dans les districts d'intervention que dans les districts témoins (+1,08 ; IC à 95% 0,63­1,53 ; P = 0,001). CONCLUSIONS: Une intervention de formation au leadership et à la gestion a permis d'accroître l'utilisation d'outils de leadership et de gestion parmi les cadres intermédiaires et d'améliorer la perception de la qualité de la supervision parmi les prestataires dans les districts d'intervention par rapport aux districts de contrôle en Ouganda. Ces résultats suggèrent que l'amélioration du leadership et de la gestion chez les gestionnaires a contribué à l'augmentation de l'utilisation du TPI chez les personnes handicapées dans les districts d'intervention de l'essai SEARCH-IPT.

Update on World Health Organization HIV drug resistance prevention and assessment strategy: 2004-2011.

The HIV drug resistance (HIVDR) prevention and assessment strategy, developed by the World Health Organization (WHO) in partnership with HIVResNet, includes monitoring of HIVDR early warning indicators, surveys to assess acquired and transmitted HIVDR, and development of an accredited HIVDR genotyping laboratory network to support survey implementation in resource-limited settings. As of June 2011, 52 countries had implemented at least 1 element of the strategy, and 27 laboratories had been accredited. As access to antiretrovirals expands under the WHO/Joint United Nations Programme on HIV/AIDS Treatment 2.0 initiative, it is essential to strengthen HIVDR surveillance efforts in the face of increasing concern about HIVDR emergence and transmission.

A randomized trial of punctuated antiretroviral therapy in Ugandan HIV-seropositive adults with pulmonary tuberculosis and CD4⁺ T-cell counts of ≥ 350 cells/µL.

BACKGROUND: Optimal treatment of human immunodeficiency virus (HIV)-associated tuberculosis in patients with high CD4⁺ T-cell counts is unknown. Suppression of viral replication during therapy for tuberculosis may block effects of immune activation on T cells and slow HIV disease progression. METHODS: We conducted a randomized trial in 214 HIV-infected patients with active tuberculosis and CD4⁺ T-cell counts of ≥ 350 cells/µL to determine whether 6 months of antiretroviral therapy given during tuberculosis treatment would improve clinical outcomes. Subjects were randomized to receive 6 months of abacavir-lamivudine-zidovudine concurrent with tuberculosis therapy or delayed antiretroviral therapy. Endpoints were CD4⁺ T-cell counts of < 250 cells/µL, AIDS, or death. RESULTS: Intervention and comparison arms had similar median CD4⁺ counts (517 and 534 cells/µL, respectively) and HIV RNA levels (4.6 and 4.7 log10 copies/µL, respectively). Viral suppression was achieved in 86% of patients allocated to intervention. Seventeen subjects (15.6%) in the intervention arm developed study outcome compared to 25 subjects (22.8%) in the comparison arm (P = .17). Grade 3 or 4 adverse events were less frequent in the intervention arm. By 2 months, 90% of subjects in both arms were culture-negative for tuberculosis. CONCLUSIONS: Short-term antiretroviral therapy during tuberculosis treatment in patients with CD4⁺T-cell counts of >350 cells/µL was safe and associated with clinical benefits.

Viral dynamics of acute HIV-1 infection.

Viral dynamics were intensively investigated in eight patients with acute HIV infection to define the earliest rates of change in plasma HIV RNA before and after the start of antiretroviral therapy. We report the first estimates of the basic reproductive number (R(0)), the number of cells infected by the progeny of an infected cell during its lifetime when target cells are not depleted. The mean initial viral doubling time was 10 h, and the peak of viremia occurred 21 d after reported HIV exposure. The spontaneous rate of decline (alpha) was highly variable among individuals. The phase 1 viral decay rate (delta(I) = 0.3/day) in subjects initiating potent antiretroviral therapy during acute HIV infection was similar to estimates from treated subjects with chronic HIV infection. The doubling time in two subjects who discontinued antiretroviral therapy was almost five times slower than during acute infection. The mean basic reproductive number (R(0)) of 19.3 during the logarithmic growth phase of primary HIV infection suggested that a vaccine or postexposure prophylaxis of at least 95% efficacy would be needed to extinguish productive viral infection in the absence of drug resistance or viral latency. These measurements provide a basis for comparison of vaccine and other strategies and support the validity of the simian immunodeficiency virus macaque model of acute HIV infection.

HIV-specific CD8(+) T cells produce antiviral cytokines but are impaired in cytolytic function.

The use of peptide-human histocompatibility leukocyte antigen (HLA) class I tetrameric complexes to identify antigen-specific CD8(+) T cells has provided a major development in our understanding of their role in controlling viral infections. However, questions remain about the exact function of these cells, particularly in HIV infection. Virus-specific cytotoxic T lymphocytes exert much of their activity by secreting soluble factors such as cytokines and chemokines. We describe here a method that combines the use of tetramers and intracellular staining to examine the functional heterogeneity of antigen-specific CD8(+) T cells ex vivo. After stimulation by specific peptide antigen, secretion of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, macrophage inflammatory protein (MIP)-1beta, and perforin is analyzed by FACS((R)) within the tetramer-positive population in peripheral blood. Using this method, we have assessed the functional phenotype of HIV-specific CD8(+) T cells compared with cytomegalovirus (CMV)-specific CD8(+) T cells in HIV chronic infection. We show that the majority of circulating CD8(+) T cells specific for CMV and HIV antigens are functionally active with regards to the secretion of antiviral cytokines in response to antigen, although a subset of tetramer-staining cells was identified that secretes IFN-gamma and MIP-1beta but not TNF-alpha. However, a striking finding is that HIV-specific CD8(+) T cells express significantly lower levels of perforin than CMV-specific CD8(+) T cells. This lack of perforin is linked with persistent CD27 expression on HIV-specific cells, suggesting impaired maturation, and specific lysis ex vivo is lower for HIV-specific compared with CMV-specific cells from the same donor. Thus, HIV-specific CD8(+) T cells are impaired in cytolytic activity.

Recovery of replication-competent HIV despite prolonged suppression of plasma viremia.

In evaluating current combination drug regimens for treatment of human immunodeficiency virus (HIV) disease, it is important to determine the existence of viral reservoirs. After depletion of CD8 cells from the peripheral blood mononuclear cells (PBMCs) of both patients and normal donors, activation of patient CD4 lymphocytes with immobilized antibodies to CD3 and CD28 enabled the isolation of virus from PBMCs of six patients despite the suppression of their plasma HIV RNA to fewer than 50 copies per milliliter for up to 2 years. Partial sequencing of HIV pol revealed no new drug resistance mutations or discernible evolution, providing evidence for viral latency rather than drug failure.

Sexual transmission and propagation of SIV and HIV in resting and activated CD4+ T cells.

In sexual transmission of simian immunodeficiency virus, and early and later stages of human immunodeficiency virus-type 1 (HIV-1) infection, both viruses were found to replicate predominantly in CD4(+) T cells at the portal of entry and in lymphoid tissues. Infection was propagated not only in activated and proliferating T cells but also, surprisingly, in resting T cells. The infected proliferating cells correspond to the short-lived population that produces the bulk of HIV-1. Most of the HIV-1-infected resting T cells persisted after antiretroviral therapy. Latently and chronically infected cells that may be derived from this population pose challenges to eradicating infection and developing an effective vaccine.

Management of HIV-infected patients with MDR- and XDR-TB in resource-limited settings.

The emergence of extensively drug-resistant tuberculosis (XDR-TB) poses a significant public health threat for human immunodeficiency virus (HIV) programmes and tuberculosis (TB) control efforts. Recent reports demonstrate high mortality rates among HIV-infected multidrug-resistant (MDR) and XDR-TB patients compared to those without HIV infection. Transmission of these highly resistant TB strains is occurring both within health facilities and in the community. We review the principles of a sound public health approach to this problem, including early diagnosis, treatment for suspected disease, patient support and adherence and sound infection control measures. In the context of drug-resistant TB, we elaborate on current World Health Organization antiretroviral guidelines addressing management issues related to timing of antiretroviral treatment (ART), drug interactions and drug toxicities among patients receiving both ART and second-line TB regimens. We highlight the important research agenda that exists at the intersection of MDR- and XDR-TB and HIV disease.

Selective expansion of human gamma delta T cells by monocytes infected with live Mycobacterium tuberculosis.

Gamma delta (gamma delta) T cell receptor (TCR) expressing T cells comprise 3% of human peripheral blood lymphocytes, yet their role in the immune response remains largely unknown. There is evidence both in humans and in animal models that these cells participate in the immune response to mycobacterial antigens. In mice, exposure to mycobacterial antigens leads to the expansion of gamma delta T cells in draining lymph nodes and lungs. In humans, gamma delta T cell lines with reactivity to mycobacterial antigens have been derived from synovial fluid of a rheumatoid arthritis patient, skin lesions of leprosy patients, and peripheral blood of a healthy tuberculin reactor. Very little is known, however, about the factors which induce human gamma delta T cells to expand. In studies comparing the human T cell response to live and heat-killed Mycobacterium tuberculosis (MT), we have found that monocytes infected with live MT are very effective inducers of human gamma delta T cell expansion. After 7 d of exposure to live MT, gamma delta T cells were greatly increased in all healthy tuberculin reactors (PPD+) tested and frequently were the predominant T cell population. In contrast, heat-killed MT or purified protein products of MT induced a CD4+, alpha beta TCR+ T cell response with very little increase in gamma delta T cells. Furthermore, a similar selective induction of gamma delta T cells was observed when monocytes infected with live Salmonella were used to stimulate T cells. Heat-killed Salmonella, like heat-killed MT, induced a predominantly CD4+ alpha beta TCR+ T cell response. These findings suggest that human gamma delta T cells are a major reactive T cell population during the early stages of infection with living intracellular bacteria and are therefore likely to exert an important role in the initial interaction between host and parasite.

Identification of antigens of Mycobacterium tuberculosis using human monoclonal antibodies.

Pleural tuberculosis constitutes a human model of local protective immunity to mycobacterial infection as the disease is usually self-limited and recurrent pleurisy is rare. To identify potentially protective antigens of Mycobacterium tuberculosis, 37 human pleural fluid B cell clones were established using EBV and their supernatants assayed by ELISA and Western blot for antibody reactivity with M. tuberculosis sonicate and culture filtrate. One antibody identified 29,000, 31,000, and 33,000 bands in culture filtrate, and 31,000, 33,000, and 47,000 bands in sonicate; its species reactivity by ELISA was limited to M. tuberculosis. Eight antibodies identified a 31,000 band in culture filtrate and a 68,000 band in M. tuberculosis sonicate, suggesting recognition of a secreted antigen. The species crossreactivity of these eight antibodies extended to M. avium. Six antibodies identified multiple bands and had crossreactivity that included M. avium and M. kansasii. There was no reactivity with recombinant M. tuberculosis 65,000 antigen. Tuberculous pleurisy may prove useful in the identification of potentially protective mycobacterial antigens, particularly those secreted during active infection, and thus accessible to the human immune response.

Elevated HIV seroprevalence and risk behavior among Ugandan TB suspects: implications for HIV testing and prevention.

OBJECTIVES: Voluntary counseling and testing (VCT) for the human immunodeficiency virus (HIV) is recommended for persons treated for tuberculosis (TB). Opportunities to diagnose HIV may be missed by limiting HIV testing to only persons diagnosed with TB. Among TB suspects in Uganda, we determined HIV prevalence, risk behaviors, and willingness to refer family for VCT. METHODS: Consenting adult patients presenting for evaluation at a referral TB clinic received same-day VCT. TB diagnosis data were abstracted from clinical records. RESULTS: Among 665 eligible patients, 565 (85%) consented to VCT. Among these, 238 (42%) were HIV-positive. Of the HIV-infected patients, 37% had received a non-TB diagnosis. HIV seroprevalence was higher in patients with a non-TB diagnosis (49%) than those diagnosed with TB (39%) (P = 0.02). Fewer than 6% of HIV-infected patients reported always using condoms with sexual partners. The majority of patients (86%) reported being 'very willing' to refer family members for VCT. CONCLUSIONS: Over 35% of HIV-infected cases in our population would have been undetected if HIV testing was limited to cases with diagnosed TB. The high HIV seroprevalence in both TB and non-TB cases merits HIV testing for all patients evaluated at TB clinics. HIV-infected TB suspects reporting high-risk behavior are at risk for HIV transmission, and should receive risk-reduction counseling.

Antiretroviral Therapy With Efavirenz Accentuates Pregnancy-Associated Reduction of Dihydroartemisinin-Piperaquine Exposure During Malaria Chemoprevention.

Dihydroartemisinin (DHA)-piperaquine is promising for malaria chemoprevention in pregnancy. We assessed the impacts of pregnancy and efavirenz-based antiretroviral therapy on exposure to DHA and piperaquine in pregnant Ugandan women. Intensive sampling was performed at 28 weeks gestation in 31 HIV-uninfected pregnant women, in 27 HIV-infected pregnant women receiving efavirenz, and in 30 HIV-uninfected nonpregnant women. DHA peak concentration and area under the concentration time curve (AUC0-8hr ) were 50% and 47% lower, respectively, and piperaquine AUC0-21d was 40% lower in pregnant women compared to nonpregnant women. DHA AUC0-8hr and piperaquine AUC0-21d were 27% and 38% lower, respectively, in pregnant women receiving efavirenz compared to HIV-uninfected pregnant women. Exposure to DHA and piperaquine were lower among pregnant women and particularly in women on efavirenz, suggesting a need for dose modifications. The study of modified dosing strategies for these populations is urgently needed.

New antiretrovirals and new combinations.

The appearance in the clinic of two to three new antiretroviral agents yearly since 1995 has permitted unprecedented advances in HIV treatment. This remarkable pace of drug development is a testimony to an extraordinary international effort involving scientists, clinicians, governments, community activists and industry dedicated to the rapid and safe development of novel therapies. New drugs present the opportunity to improve HIV therapy. They also create an enormous challenge to the clinician, who must constantly assimilate data on new drugs and incorporate this information into practical management strategies. Combination therapy has proven the most effective approach to treat HIV disease. The profound and sustained viral suppression achievable with combinations such as indinavir (IDV), lamivudine (3TC) and zidovudine (ZDV) have resulted in a dramatic shift in HIV treatment paradigms over the last year. The full potential of combination therapy with available drugs has yet to be realized as only a limited number of the possible combinations incorporating new drugs have been fully tested. Even drugs available for many years may have untapped potential. Didanosine (ddI) and stavudine (d4T), once thought to be contraindicated in combination because of their overlapping peripheral neuropathy toxicity, have proven well tolerated and effective. Combination therapy can increase antiviral suppression, prevent drug resistance, optimize drug exposure and simplify dosing, but it can also result in pharmacologic antagonism, subtherapeutic drug concentrations and unexpected toxicities. Clinical studies have confirmed in vitro studies showing pharmacologic antagonism for the combination of ZDV and d4T. Combining protease inhibitors with each other or with non-nucleoside reverse transcriptase inhibitors is complicated by effects both classes of drugs have on drug metabolism and clearance. These observations underline the importance of carefully conducted clinical studies to characterize safety, pharmacokinetics and efficacy of combination therapies. In this review, we will first summarize the clinical profile of new drugs which either became commercially available last year [nelfinavir, nevirapine, delavirdine (DLV)] or are in the late stages of clinical development (DMP-266, abacavir and 141W94). Later we will summarize new data on nucleoside, protease inhibitor and non-nucleoside reverse transcriptase combination regimens. Finally, we will briefly mention new drugs in early stages of development.

Plasma population pharmacokinetics and penetration into cerebrospinal fluid of indinavir in combination with zidovudine and lamivudine in HIV-1-infected patients.

OBJECTIVES: To evaluate plasma population pharmacokinetics and penetration into cerebrospinal fluid (CSF) by indinavir (IDV) in HIV-infected individuals receiving IDV, zidovudine and lamivudine. METHODS: Plasma population pharmacokinetic analysis was performed on 805 IDV plasma values from 171 patients, using a non-linear mixed-effects modeling approach. CSF data from 19 patients were analyzed using an individual approach. RESULTS: Mean individual Bayesian estimates for oral clearance (CL) and volume of distribution (V) by the final model that incorporated interoccasion variability were 0.75 l/h per kg [coefficient of variation (CV) 54.8%] and 1.74 l/kg (CV 82.7%), respectively. Mean model-predicted plasma IDV level at 8 h, maximal level, area under the plasma level-time curve up to 8 h and plasma half-life were 0.42 micromol/l (CV 57.5%), 9.51 micromol/l (CV 47.3%), 29.56 micromol/l x h (CV 46.9%) and 1.50 h (CV 20.9%), respectively. The mean IDV CSF level was 0.11 micromol/l (CV 49.7%) and the mean CSF:plasma concentration ratio was 0.017. CONCLUSIONS: Population estimates of pharmacokinetic parameters of IDV and its CSF penetration were in excellent agreement with previously reported data from individual analyses. Intraindividual interoccasion variability of IDV pharmacokinetics was estimated to be of similar order of magnitude to its interindividual variability, which may affect response to long-term antiretroviral therapy involving IDV. CSF levels of IDV exceeded its in vitro 95% inhibitory concentration of HIV replication. Given that CSF is virtually free of protein, viral suppression in the central nervous system should be achievable with an IDV-containing regimen.

Effect of chemokine receptor gene polymorphisms on the response to potent antiretroviral therapy.

BACKGROUND: Both the natural history of HIV infection and the response to antiretroviral therapy are heterogeneous. Polymorphisms in chemokine receptor genes modulate the natural history of HIV-1 infection. In comparison with subjects with other genotypes, the prognosis for HIV-1-infected CCR5-delta32 heterozygotes is more favorable and that for CCR5 promoter allele 59029A homozygotes is less favorable. METHODS: HIV-1-infected adults with a CD4+ lymphocyte count > or = 200 cells x 10(6)/l and a plasma HIV RNA level > or = 1000 copies/ml were treated with indinavir, zidovudine and lamivudine for 6 months. HIV RNA levels were measured at 4-week intervals. Genotyping for chemokine receptor gene polymorphisms (CCR5-delta32, CCR5 59029A/G, CCR2-641) was performed. We examined whether the time to first HIV RNA < 200 copies/ml, frequency of viral suppression failure (HIV RNA > or = 200 copies/ml between weeks 16 and 28 of therapy), or reduction from the pre-treatment HIV RNA level differed by genotype. RESULTS: Time to first HIV RNA < 200 copies/ml was not predicted by genotype. Among 272 Caucasian patients, viral suppression failure was more common among patients with the CCR5 +/+ ¿ CCR2+/+ ¿ CCR5-59029 A/A genotype (28%) than among all other subjects combined (relative risk, 2.0; P = 0.06). After 24 weeks of therapy, genotype groups differed in the reduction of the HIV RNA level from baseline (P = 0.02); patients with the CCR5 +/+ ¿ CCR2+/+ ¿ CCR5-59029 A/A genotype had a mean reduction of 2.12 log10 copies/ml compared to 2.64 log10 copies/ml among all other groups combined. CONCLUSION: Polymorphisms in chemokine receptor genes may explain some of the heterogeneity in sustaining viral suppression observed among patients receiving potent antiretroviral therapy.

Dynamics of HIV-1 viral load rebound among patients with previous suppression of viral replication.

OBJECTIVE: To model the dynamics of HIV-1 rebound in patients receiving suboptimal therapy after suppression of plasma viremia to < 200 copies/ml by triple combination therapy. DESIGN: Mathematical modeling of data from 23 patients switched to indinavir maintenance therapy after viral replication was suppressed with a combination of indinavir, zidovudine and lamivudine. Modeling of HIV-1 rebound among 24 patients on zidovudine/lamivudine maintenance was also performed for comparison. METHODS: Evaluation of slopes of rebound and of their heterogeneity; calculation of the basic reproductive number (Ro, the number of newly infected cells arising from each productively infected cell); regression analyses for predictors of the slope of rebound. RESULTS: Rebound of plasma HIV RNA followed a sigmoid curve with an initial exponential phase. There was significant heterogeneity in the slopes of rebound for individual patients (P < 0.001). In the indinavir maintenance rebounds, the average initial slope was estimated to be 0.587/day (doubling time 1.2 days). The slopes of rebound in patients on zidovudine/lamivudine maintenance tended to be less steep on average (P = 0.025). Among patients taking indinavir maintenance, the average Ro for the initial rebound of viremia was 4.3; in multivariate regressions, the slope of rebound was steeper during early rebound and in patients with higher viral load at the start of triple therapy or a higher CD4 cell count when indinavir monotherapy was initiated. The slope was less steep in patients with a greater increase in the number of CD4 cells during triple therapy. CONCLUSIONS: The rates of viral load increase among patients with viral rebound while receiving less than triple therapy are similar to those reported in patients interrupting therapy. Variability among patients may depend on viral fitness, target cell availability and extent of immune reconstitution.

Effects of treatment intensification with hydroxyurea in HIV-infected patients with virologic suppression.

BACKGROUND: Virologic rebound can result from suboptimal antiviral potency in combination antiretroviral therapy. DESIGN: Multicenter, partially blinded, prospective, randomized study of 202 HIV-infected subjects to determine whether therapy intensification improves long-term rates of virologic suppression. METHODS: Subjects had plasma HIV RNA < 200 copies/ml, CD4 cell count of > 200 x 10(6) cells/l, and treatment with indinavir (IDV) + zidovudine (ZDV) + lamivudine (3TC) for at least 6 months before randomization to stay on this regimen or to receive IDV + didanosine (ddI) + stavudine (d4T) plus or minus hydroxyurea (HU) (600 mg twice daily). Treatment failure was defined as either confirmed rebound of HIV RNA level to > 200 copies/ml or a drug toxicity necessitating treatment discontinuation. RESULTS: Treatment failure occurred more frequently in subjects randomized to the HU-containing arm (32.4%), than in those taking IDV + ddI + d4T (17.6%) or IDV + ZDV + 3TC (7.6%). The time to treatment failure was shorter for the HU-containing arm compared with the IDV + ZDV + 3TC (P < 0.0001) or IDV + ddI + d4T arms (P = 0.032). Dose-limiting toxicities rather than virologic rebound accounted for the differences between treatment failure among the study arms. Pancreatitis led to treatment discontinuation in 4% of subjects in treatment arms containing ddI + d4T. Three subjects with pancreatitis died, all randomized to the HU-containing arm. CONCLUSIONS: Switching to IDV + ddI + d4T + HU in patients treated with IDV + ZDV + 3TC was associated with a worse outcome, principally because of drug toxicity.

Polymicrobial bacteremia in the late 1980s: predictors of outcome and review of the literature.

Although polymicrobial bacteremia has been described in several previous series, there has been no recent study of patients using rigorous statistical analysis. Our objective was to characterize a present-day patient population with polymicrobial bacteremia and to define factors prognostic of survival. Polymicrobial bacteremia accounted for 6% of all positive blood cultures at a university hospital and a Veterans Administration hospital over a 2 1/2 year period in the late 1980s. The majority of these patients were elderly with significant underlying diseases, notably malignancies, and 56% of all episodes were nosocomially acquired. Enterobacteriaceae have remained the most common organisms, though the frequency of gram-positive cocci isolated has increased compared to older studies. Gastrointestinal, genitourinary, and skin and soft-tissue sources were the most common, although the incidence of infections due to central venous catheters appeared to be increasing. The source of 25% of bacteremia was not identified despite newer diagnostic techniques. By univariate analysis, mortality, which was 36% overall, correlated with thrombocytopenia, respiratory failure, disseminated intravascular coagulation, encephalopathy, severity of underlying disease, hemolysis, adult respiratory distress syndrome, use of steroids, renal insufficiency, institution, presence of central lines, and nosocomial acquisition. Using stepwise logistic regression analysis, mortality was predicted by respiratory failure, severity of underlying disease, and hemolysis. We conclude that polymicrobial bacteremia remains an important entity in the present-day hospitalized population, with an increasing frequency of gram-positive organisms and catheter sources, and a large proportion of undiagnosed etiologies.

Comparative performance of high-density oligonucleotide sequencing and dideoxynucleotide sequencing of HIV type 1 pol from clinical samples.

The performance of the high-density oligonucleotide array methodology (GeneChip) in detecting drug resistance mutations in HIV-1 pol was compared with that of automated dideoxynucleotide sequencing (ABI) of clinical samples, viral stocks, and plasmid-derived NL4-3 clones. Sequences from 29 clinical samples (plasma RNA, n = 17; lymph node RNA, n = 5; lymph node DNA, n = 7) from 12 patients, from 6 viral stock RNA samples, and from 13 NL4-3 clones were generated by both methods. Editing was done independently by a different investigator for each method before comparing the sequences. In addition, NL4-3 wild type (WT) and mutants were mixed in varying concentrations and sequenced by both methods. Overall, a concordance of 99.1% was found for a total of 30,865 bases compared. The comparison of clinical samples (plasma RNA and lymph node RNA and DNA) showed a slightly lower match of base calls, 98.8% for 19,831 nucleotides compared (protease region, 99.5%, n = 8272; RT region, 98.3%, n = 11,316), than for viral stocks and NL4-3 clones (protease region, 99.8%; RT region, 99.5%). Artificial mixing experiments showed a bias toward calling wild-type bases by GeneChip. Discordant base calls are most likely due to differential detection of mixtures. The concordance between GeneChip and ABI was high and appeared dependent on the nature of the templates (directly amplified versus cloned) and the complexity of mixes.