A novel immunization strategy using cytokine/chemokines induces new effective systemic immune responses, and frequent complete regressions of human metastatic melanoma.

Immune responses have been elicited by a variety of cancer vaccines, but seldom induce regressions of established cancers in humans. As a novel therapeutic immunization strategy, we tested the hypothesis that multiple cytokines/chemokines secreted early in secondary responses ex-vivo might mimic the secretory environment guiding new immune responses. The early development of immune responses is regulated by multiple cytokines/chemokines acting together, which at physiologic concentrations act locally in concert with antigen to have non-specific effects on adjacent cells, including the maturation of dendritic cells, homing and retention of T cells at the site of antigen, and the differentiation and expansion of T cell clones with appropriate receptors. We postulated that repeated injections into a metastasis of an exogenous chemokine/cytokine mixture might establish the environment of an immune response and allow circulating T cell clones to self- select for mutant neo-epitopes in the tumor and generate systemic immune responses. To test this idea we injected some metastases in patients with multiple cutaneous melanoma nodules while never injecting other control metastases in the same patient. New immune responses were identified by the development of dense lymphocytic infiltrates in never-injected metastases, and the frequent complete regression of never-injected metastases, a surprising observation. 70% of subjects developed dense infiltrates of cytotoxic CD8 cells in the center and margin of never-injected metastases; 38% of subjects had complete and often durable regressions of all metastases, without the use of check-point inhibitors, suggesting that, as a proof-of-principle, an immunization strategy can control advanced human metastatic melanoma.

Epigenetic mechanisms, T-cell activation, and CCR5 genetics interact to regulate T-cell expression of CCR5, the major HIV-1 coreceptor.

T-cell expression levels of CC chemokine receptor 5 (CCR5) are a critical determinant of HIV/AIDS susceptibility, and manifest wide variations (i) between T-cell subsets and among individuals and (ii) in T-cell activation-induced increases in expression levels. We demonstrate that a unifying mechanism for this variation is differences in constitutive and T-cell activation-induced DNA methylation status of CCR5 cis-regulatory regions (cis-regions). Commencing at an evolutionarily conserved CpG (CpG -41), CCR5 cis-regions manifest lower vs. higher methylation in T cells with higher vs. lower CCR5 levels (memory vs. naïve T cells) and in memory T cells with higher vs. lower CCR5 levels. HIV-related and in vitro induced T-cell activation is associated with demethylation of these cis-regions. CCR5 haplotypes associated with increased vs. decreased gene/surface expression levels and HIV/AIDS susceptibility magnify vs. dampen T-cell activation-associated demethylation. Methylation status of CCR5 intron 2 explains a larger proportion of the variation in CCR5 levels than genotype or T-cell activation. The ancestral, protective CCR5-HHA haplotype bears a polymorphism at CpG -41 that is (i) specific to southern Africa, (ii) abrogates binding of the transcription factor CREB1 to this cis-region, and (iii) exhibits a trend for overrepresentation in persons with reduced susceptibility to HIV and disease progression. Genotypes lacking the CCR5-Δ32 mutation but with hypermethylated cis-regions have CCR5 levels similar to genotypes heterozygous for CCR5-Δ32. In HIV-infected individuals, CCR5 cis-regions remain demethylated, despite restoration of CD4+ counts (≥800 cells per mm(3)) with antiretroviral therapy. Thus, methylation content of CCR5 cis-regions is a central epigenetic determinant of T-cell CCR5 levels, and possibly HIV-related outcomes.

Early detection of HIV infection among Kenyan infants using a reverse transcriptase activity assay.

Two hundred HIV-exposed Kenyan infants were tested for HIV infection at birth and at age 6, 12, 24 and 48 weeks, by DNA polymerase chain reaction (PCR) and Cavidi reverse transcriptase (RT) assays and after age 18 months by HIV antibody test. Eleven (5.5%) infants became HIV infected. In 6 infants, positive RT preceded positive DNA PCR. The use of RT assay may facilitate earlier HIV diagnosis in infants.

Sex differences in the incidence of peripheral neuropathy among Kenyans initiating antiretroviral therapy.

BACKGROUND: Peripheral neuropathy (PN) is common among patients receiving antiretroviral therapy (ART) in resource-limited settings. We report the incidence of and risk factors for PN among human immunodeficiency virus (HIV)-infected Kenyan adults initiating ART. METHODS: An inception cohort was formed of adults initiating ART. They were screened for PN at baseline and every 3 months for 1 year. We used the validated Brief Peripheral Neuropathy Screen (BPNS) that includes symptoms and signs (vibration perception and ankle reflexes) of PN. RESULTS: Twenty-two (11%) of 199 patients had PN at baseline screening. One hundred fifty patients without evidence of PN at baseline were followed for a median of 366 days (interquartile range, 351-399). The incidence of PN was 11.9 per 100 person-years (95% confidence interval [CI], 6.9-19.1) and was higher in women than men (17.7 vs 1.9 per 100 person-years; rate ratio, 9.6; 95% CI, 1.27-72, P = .03). In stratified analyses, female sex remained statistically significant after adjustment for each of the following variables: age, CD4 cell count, body mass index, ART regimen, and tuberculosis treatment. Stratifying hemoglobin levels decreased the hazard ratio from 9.6 to 7.40 (P = .05), with higher levels corresponding to a lower risk of PN. CONCLUSIONS: HIV-infected Kenyan women were almost 10 times more likely than men to develop PN in the first year of ART. The risk decreased slightly at higher hemoglobin levels. Preventing or treating anemia in women before ART initiation and implementing BPNS during the first year of ART, the period of highest risk, could ameliorate the risk of PN.

Implementation of a validated peripheral neuropathy screening tool in patients receiving antiretroviral therapy in Mombasa, Kenya.

Limited objective data are available for the prevalence of peripheral neuropathy (PN) among antiretroviral (ART)-treated human immunodeficiency virus (HIV)-infected patients in resource-limited settings. A validated neuropathy-screening tool was integrated into routine ART visits at an HIV clinic in Mombasa, Kenya. Diagnosis of PN required at least one symptom and either abnormal vibratory sensation or deep tendon reflex bilaterally. Among 102 consecutively screened patients, 63% were women, 62% were receiving ART for < or = 1 year, and 86% were receiving a stavudine (D4T)-based regimen. Thirty-seven (36%) had PN. Univariate analysis showed that current D4T use was protective against PN (P = 0.03) and older age was a marginal risk factor (P = 0.05). Multivariate analysis showed that older age was a risk factor for neuropathy (P = 0.04). Peripheral neuropathy was common, particularly among older HIV-infected adults in Kenya. The protective association with current D4T use likely represents survivor effect bias. Longitudinal studies using this screen will help further characterize PN in resource-limited settings.

Evidence of dysregulation of dendritic cells in primary HIV infection.

Myeloid and plasmacytoid dendritic cells (DCs) are important mediators of both innate and adaptive immunity against pathogens such as HIV. During the course of HIV infection, blood DC numbers fall substantially. In the present study, we sought to determine how early in HIV infection the reduction occurs and whether the remaining DC subsets maintain functional capacity. We find that both myeloid DC and plasmacytoid DC levels decline very early during acute HIV infection. Despite the initial reduction in numbers, those DCs that remain in circulation retain their function and are able to stimulate allogeneic T-cell responses, and up-regulate maturation markers plus produce cytokines/chemokines in response to stimulation with TLR7/8 agonists. Notably, DCs from HIV-infected subjects produced significantly higher levels of cytokines/chemokines in response to stimulation with TLR7/8 agonists than DCs from uninfected controls. Further examination of gene expression profiles indicated in vivo activation, either directly or indirectly, of DCs during HIV infection. Taken together, our data demonstrate that despite the reduction in circulating DC numbers, those that remain in the blood display hyperfunctionality and implicates a possible role for DCs in promoting chronic immune activation.

Measurement of antiretroviral drugs in the lungs of HIV-infected patients.

AIMS: Prior studies have shown that HAART is associated with decreased HIV viral load in the lungs. The correlation between antiretroviral exposure in bronchoalveolar lavage (BAL) fluid and virologic response was evaluated in patients starting HAART and enrolled in The AIDS Clinical Trial Group Protocol 723. MATERIALS #ENTITYSTARTX00026; METHODS: A total of 24 subjects underwent blood and BAL sampling prior to starting HAART, and after 4 and 24 weeks of HAART. Drug concentrations and HIV RNA were measured in paired plasma and BAL samples. RESULTS: Antiretroviral drugs, including efavirenz, were detectable in BAL fluid of HIV-infected subjects beginning HAART. Efavirenz was also associated with a higher likelihood of clearing HIV RNA from the lungs. CONCLUSION: These results suggest the excellent pulmonary virologic response to antiretroviral therapy may, in part, be due to penetration of antiretroviral drugs into the alveolar compartment.

The Development and Implementation of an Outreach Program to Identify Acute and Recent HIV Infections in New York City.

INTRODUCTION: Since 2004, the authors have been operating First Call NYU, an outreach program to identify acute and recent HIV infections, also called primary HIV infections, among targeted at-risk communities in the New York City (NYC) metropolitan area. MATERIALS AND METHODOLOGY: First Call NYU employed mass media advertising campaigns, outreach to healthcare providers in NYC, and Internet-based efforts including search engine optimization (SEO) and Internet-based advertising to achieve these goals. RESULTS: Between October 2004 and October 2008, 571 individuals were screened through this program, leading to 446 unique, in-person screening visits. 47 primary HIV infections, including 14 acute and 33 recent HIV infections, were identified. DISCUSSION: Internet and traditional recruitment methods can be used to increase self-referrals for screening following possible exposure to HIV. CONCLUSION: Community education of at-risk groups, with the goal of increased self-diagnosis of possible acute HIV infection, may be a useful addition to traditional efforts to identify such individuals.

Susceptibility of human Th17 cells to human immunodeficiency virus and their perturbation during infection.

BACKGROUND: Identification of the Th17 T cell subset as important mediators of host defense and pathology prompted us to determine their susceptibility to human immunodeficiency virus (HIV) infection. METHODS AND RESULTS: We found that a sizeable portion of Th17 cells express HIV coreceptor CCR5 and produce very low levels of CCR5 ligands macrophage inflammatory protein (MIP)-1alpha and MIP-1beta. Accordingly, CCR5(+) Th17 cells were efficiently infected with CCR5-tropic HIV and were depleted during viral replication in vitro. Remarkably, HIV-infected individuals receiving treatment had significantly reduced Th17 cell counts, compared with HIV-uninfected subjects, regardless of viral load or CD4 cell count, whereas treatment-naive subjects had normal levels. However, there was a preferential reduction in CCR5(+) T cells that were also CCR6 positive, which is expressed on all Th17 cells, compared with CCR6(-)CCR5(+) cells, in both treated and untreated HIV-infected subjects. This observation suggests preferential targeting of CCR6(+)CCR5(+) Th17 cells by CCR5-tropic viruses in vivo. Th17 cell levels also inversely correlated with activated CD4(+) T cells in HIV-infected individuals who are receiving treatment. CONCLUSIONS: Our findings suggest a complex perturbation of Th17 subsets during the course of HIV disease potentially through both direct viral infection and virus indirect mechanisms, such as immune activation.

A strategy for eliciting antibodies against cryptic, conserved, conformationally dependent epitopes of HIV envelope glycoprotein.

BACKGROUND: Novel strategies are needed for the elicitation of broadly neutralizing antibodies to the HIV envelope glycoprotein, gp120. Experimental evidence suggests that combinations of antibodies that are broadly neutralizing in vitro may protect against challenge with HIV in nonhuman primates, and a small number of these antibodies have been selected by repertoire sampling of B cells and by the fractionation of antiserum from some patients with prolonged disease. Yet no additional strategies for identifying conserved epitopes, eliciting antibodies to these epitopes, and determining whether these epitopes are accessible to antibodies have been successful to date. The defining of additional conserved, accessible epitopes against which one can elicit antibodies will increase the probability that some may be the targets of broadly neutralizing antibodies. METHODOLOGY/PRINCIPAL FINDINGS: We postulate that additional cryptic epitopes of gp120 are present, against which neutralizing antibodies might be elicited even though these antibodies are not elicited by gp120, and that many of these epitopes may be accessible to antibodies should they be formed. We demonstrate a strategy for eliciting antibodies in mice against selected cryptic, conformationally dependent conserved epitopes of gp120 by immunizing with multiple identical copies of covalently linked peptides (MCPs). This has been achieved with MCPs representing 3 different domains of gp120. We show that some cryptic epitopes on gp120 are accessible to the elicited antibodies, and some epitopes in the CD4 binding region are not accessible. The antibodies bind to gp120 with relatively high affinity, and bind to oligomeric gp120 on the surface of infected cells. CONCLUSIONS/SIGNIFICANCE: Immunization with MCPs comprised of selected peptides of HIV gp120 is able to elicit antibodies against conserved, conformationally dependent epitopes of gp120 that are not immunogenic when presented as gp120. Some of these cryptic epitopes are accessible to the elicited antibodies.

Monitoring virologic responses to antiretroviral therapy in HIV-infected adults in Kenya: evaluation of a low-cost viral load assay.

BACKGROUND: A key advantage of monitoring HIV viral load (VL) in persons receiving antiretroviral therapy (ART) is the ability to detect virologic failure before clinical deterioration or resistance occurs. Detection of virologic failure will help clarify the need for enhanced adherence counseling or a change to second- line therapy. Low-cost, locally performable alternates to expensive VL assays are needed where resources are limited. METHODOLOGY/PRINCIPAL FINDINGS: We monitored the response to 48-week ART in 100 treatment-naïve Kenyan adults using a low-cost VL measurement, the Cavidi reverse transcriptase (RT) assay and gold-standard assays, Roche RNA PCR and Bayer Versant HIV-1 RNA (bDNA) assays. In Altman-Bland plots, the mean difference in viral loads between the three assays was small (<0.5 log(10) copies/mL). However, the limits of agreement between the methods exceeded the biologically relevant change of 0.5 log copies/ml. Therefore, the RT assay cannot be used interchangeably with the other assays to monitor individual patients. The RT assay was 100% sensitive in detecting viral loads of > or =400 copies/ml compared to gold-standard assays. After 24 weeks of treatment, viral load measured by the RT assay was undetectable in 95% of 65 patients with undetectable RNA PCR VL (<400 copies/ml), 90% of 67 patients with undetectable bDNA VL, and 96% of 57 patients with undetectable VL in both RNA PCR and bDNA assays. The negative predictive value of the RT assay was 100% compared to either assay; the positive predictive value was 86% compared to RNA PCR and 70% compared to bDNA. CONCLUSION: The RT assay compared well with gold standard assays. Our study highlights the importance of not interchanging viral load assays when monitoring an individual patient. Furthermore, the RT assay may be limited by low positive predictive values when used in populations with low prevalence of virologic failure.

Implementation of HIV testing at 2 New York City bathhouses: from pilot to clinical service.

BACKGROUND: Commercial sex venues (e.g., bathhouses) that cater to men who have sex with men (MSM) continue to function in most urban areas. These venues present a challenge to developing strategies to prevent the spread of the human immunodeficiency virus (HIV), but they also provide opportunities for interventions to reduce the risk and rate of disease transmission. Several cities in the United States have developed programs that offer HIV testing in these venues. Similar programs have not existed before in New York City. METHODS: A pilot HIV testing program was implemented at 2 New York City bathhouses. Testing included rapid HIV testing, the use of the serologic testing algorithm for recent HIV seroconversion, and pooled plasma HIV viral load to detect and date incident and acute HIV infections. In addition to HIV tests, behavioral and demographic data were collected from 493 presumed HIV-negative participants. RESULTS: The pilot program recruited MSM who were at high risk for HIV infection. Of the 493 men tested, 20 (4%) were found to be positive for HIV, and 8 (40%) of these 20 men demonstrated evidence of acute or recent HIV infection. The program tested men often not tested in more traditional medical settings. Significant disparities were demonstrated in the testing habits of MSM who reported having sex with women and had not disclosed same-sex activities to their caregivers. CONCLUSIONS: Bathhouse-based testing for HIV infection can be implemented in New York City and would include a population of MSM who are at high risk for HIV infection. Because of the high rate of recent HIV infection, expanded testing in these venues may be a good strategy to reduce the forward transmission of HIV in this highly sexually active population.

Effect of highly active antiretroviral therapy on viral burden in the lungs of HIV-infected subjects.

BACKGROUND: Human immunodeficiency virus (HIV) is readily detectable in the lungs of infected subjects and leads to an accumulation of CD8(+) lymphocytes in the alveolar space. Although highly active antiretroviral therapy (HAART) is effective in reducing viremia, less is known about its effect on tissue compartments. The AIDS Clinical Trials Group Protocol 723 Team evaluated the effect of HAART on lung viral load and cellular constituents. METHODS: Bronchoalveolar lavage (BAL) fluid and blood were collected before initiation of HAART and again at 4 and 24 weeks after initiation of therapy. The BAL cell differential was determined, lymphocyte phenotyping was performed, and acellular BAL fluid, plasma HIV RNA load, and BAL cell and peripheral blood mononuclear cell HIV RNA and DNA loads were measured. RESULTS: HAART induced a rapid decrease in HIV that was detectable in acellular BAL fluid and a slower decrease in the HIV RNA and DNA loads in BAL cells. HAART was associated with a significant decrease in the absolute number and percentage of CD8(+) alveolar lymphocytes. There was a significant correlation between residual BAL cell DNA at 24 weeks and the absolute number of CD4(+) lymphocytes in the alveolar space. CONCLUSION: HAART is associated with a significant decrease in the pulmonary HIV burden and a return of alveolar cellular constituents to normal.

A reverse transcriptase assay for early diagnosis of infant HIV infection in resource-limited settings.

Early diagnosis of pediatric HIV infection is confounded by persistence of maternal antibodies until 18 months, necessitating the use of expensive assays such as HIV-1 DNA PCR, an untenable option in resource-limited settings. This is the first report of a low-cost, commercial, reverse transcriptase (RT) assay for the diagnosis of HIV-1 infection in infants. RT assays were performed on 42 samples from 30 HIV-exposed Kenyan infants under 15 months of age. When correlated with serologic testing conducted after 18 months, the sensitivity, specificity, positive and negative predictive values of the RT assay were 92%, 93%, 87% and 96%. A low-cost assay for infant HIV diagnosis is urgently needed, and these results merit further evaluation.

Immunological memory after exposure to variola virus, monkeypox virus, and vaccinia virus.

We compared cellular and humoral immunity to vaccinia virus (VV) in individuals exposed to 3 different orthopoxviruses: 154 individuals previously vaccinated with VV, 7 individuals with a history of monkeypox virus infection, and 8 individuals with a history of variola virus infection. Among individuals vaccinated >20 years prior, 9 (14%) of 66 individuals demonstrated VV-specific interferon (IFN)- gamma enzyme-linked immunospot (ELISPOT) assay responses; 21 (50%) of 42 had lymphoproliferative (LP) responses, and 29 (97%) of 30 had VV-specific neutralizing antibodies. One year after monkeypox virus infection, 6 of 7 individuals had IFN- gamma ELISPOT responses, all had VV-specific LP responses, and 3 of 7 had VV-specific neutralizing antibodies. Of 8 individuals with a history of variola virus infection, 1 had a VV-specific IFN- gamma ELISPOT response, 4 had LP responses against whole VV, 7 had LP responses against heat-denatured vaccinia antigen, and 7 had VV-specific neutralizing antibodies. Survivors of variola virus infection demonstrated VV-specific CD4 memory cell responses and neutralizing antibodies >40 years after infection.

Low CD4+ T cell nadir is an independent predictor of lower HIV-specific immune responses in chronically HIV-1-infected subjects receiving highly active antiretroviral therapy.

The influence of CD4(+) T cell nadirs on human immunodeficiency virus (HIV)-specific immune responses in subjects with apparently normal CD4(+) T cell counts is not known. We evaluated the frequency of HIV-1-specific immune responses in a cohort of patients with complete viral suppression (HIV-1 RNA load, <50 copies/mL) who were receiving highly active antiretroviral therapy and had a wide range of CD4(+) T cell nadirs. We found positive associations between CD4(+) T cell nadirs and the magnitude of HIV-specific CD8(+) T cell responses (P=.02) and of T cell helper responses (P=.04). These data show the CD4(+) T cell nadir to be an independent predictor of HIV-specific CD4(+) and CD8(+) T cell responses in HIV-1-infected subjects with optimal suppression of viremia.

Human immunodeficiency virus (HIV) reverse transcriptase activity correlates with HIV RNA load: implications for resource-limited settings.

Measurement of human immunodeficiency virus type 1 (HIV-1) plasma RNA levels using Roche AMPLICOR version 1.5 (HIV RNA) is an integral part of monitoring HIV-infected patients in industrialized countries. These assays are currently unaffordable in resource-limited settings. We investigated a reverse transcriptase (RT) assay as a less expensive alternative for measuring viral burden that quantifies RT enzyme activity in clinical plasma samples. A comparison of RT and HIV RNA assays was performed on 29 paired plasma samples from patients living in the United States and 21 paired plasma samples from patients living in Cameroon. RT levels correlated significantly with plasma HIV RNA viral loads in plasma from U.S. patients (r = 0.898; P < 0.001) and Cameroonian patients, a majority of whom were infected with HIV-1 clade type CRF02_AG (r = 0.669; P < 0.01). Among 32 samples with HIV viral load of >2,000 copies/ml, 97% had detectable RT activity. One Cameroon sample had undetectable RNA viral load but detectable RT activity of 3 fg/ml. The RT assay is a simple and less expensive alternative to the HIV RNA assay. Field studies comparing these assays in resource-limited settings are warranted to assess the practicality and usefulness of this assay for monitoring HIV-infected patients on antiretroviral therapy.

Activity, safety, and immunological effects of hydroxyurea added to didanosine in antiretroviral-naive and experienced HIV type 1-infected subjects: a randomized, placebo-controlled trial, ACTG 307.

We performed a 24-week, placebo-controlled, comparative trial of hydroxyurea (HU) monotherapy, didanosine(ddI) monotherapy, and the combination of ddI plus HU administered as 1000 mg qd or 1500 mg qd in antiretroviral-naive and experienced subjects with CD4+ lymphocyte counts of 200-700 cells/mm3. Enrollment included 134 subjects. HU enhanced the antiviral activity of ddI by 1.0 log10 copies/ml after 8 weeks of therapy, with sustained responses over 24 weeks. HU alone over 4 weeks had no effect. Lamivudine resistance had little impact on antiretroviral activity when examined across treatment arms. Increases in absolute CD4+ T cell counts, but not CD4+ T cell percentages, were less in subjects who received HU compared to ddI monotherapy, and lymphoproliferative responses to antigenic and mitogenic stimuli were not altered. Subjects who received HU 1500 mg were more likely to experience dose-limiting hematological toxicities compared to those who received 1000 mg, without any additional antiviral benefit. HU may continue to have a role as a component of HIV therapy.

Daily low-dose subcutaneous interleukin-2 added to single- or dual-nucleoside therapy in HIV infection does not protect against CD4+ T-cell decline or improve other indices of immune function: results of a randomized controlled clinical trial (ACTG 248).

CONTEXT: Approaches to preserve or enhance immune function in HIV-1 infection are needed. OBJECTIVES: To examine the ability of daily low-dose interleukin-2 (IL-2) in combination with antiretroviral therapy to preserve circulating CD4+ T-cell counts, the clinical safety and tolerability of this treatment, and safety with respect to changes in plasma HIV-1 RNA levels. DESIGN: Twenty-four-week, phase 2, multicenter, randomized, open-label trial conducted at 12 AIDS Clinical Trials Units between September 1995 and May 1997. PARTICIPANTS: A total of 115 HIV-infected persons with screening CD4+ T-cell counts between 300 and 700 cells/mm who were on stable single- or dual-nucleoside therapy for at least 2 months, 11% of whom were also on a protease inhibitor at study entry. INTERVENTIONS: Patients were randomly assigned to receive IL-2 at a dose of 1 million IU subcutaneously once daily plus continued anti-retroviral therapy (ART + IL-2, n = 57) vs. continued ART alone (ART alone, n = 58). IL-2 dose reductions were made for objective or subjective toxicities. All subjects randomly assigned to the IL-2 arm who interrupted ART were also required to discontinue IL-2 for the same period. MAIN OUTCOME MEASURES: The primary endpoint was a decrease in CD4 T-cell count from baseline; the safety analysis was based on change in plasma HIV RNA by bDNA; and clinical safety and tolerability were analyzed by standard clinical criteria. RESULTS: Of the patients with a baseline CD4 T-cell count recorded, 15 (27%) of 55 patients randomly assigned to ART alone had a drop of > or =25% in their CD4 T-cell count and 23 (41%) of 56 patients randomly assigned to ART + IL-2 had a drop of > or =25% in their CD4 T-cell count at some time over the 24 weeks of the study. This difference was not statistically significant. There was a statistically significant greater variance in CD4 T-cell counts in the IL-2-treated group. More patients in the IL-2 group had at least a 25% increase in CD4 T-cell counts over baseline (34 vs. 13%, P = 0.007). A comparison of grade 3 or worse toxicity showed no differences between the arms, but IL-2 was associated with significantly more grade 2 or worse general body symptoms, primarily discomfort and fatigue. There was no significant difference between the groups with regard to changes in plasma HIV RNA, lymphocyte proliferation, natural killer cell activity, skin test responses to recall antigens, or antibody responses to immunization. Plasma markers of immune activation all increased significantly in IL-2 recipients. CONCLUSIONS: In patients with baseline CD4 T-cell counts > or =300 cells/mm primarily treated with single- or dual-nucleoside ART, subcutaneously administered IL-2 at a dose of 1 million IU daily for up to 24 weeks had low toxicity but showed no consistent benefit in preventing decline in CD4 T-cell counts and minimal evidence of immunologic improvement vs. continued ART alone.