Long-term virological outcomes, failure and acquired resistance in a large cohort of Ugandan children.

OBJECTIVES: To evaluate long-term virological failure (VF) and drug resistance among HIV-infected Ugandan children on first-line ART. METHODS: In a multicentre prospective cohort study, viral load (VL) and drug resistance mutations (DRMs) were investigated at baseline and 6 monthly intervals in children (age ≤ 12 years). VF (two consecutive VLs >1000 copies/mL or death after 6 months of ART) was defined as early VF (0-24 months of ART) or late VF (25-48 months of ART). An active regimen was defined as partially active if the genotypic susceptibility score (GSS) was <3. RESULTS: Between 2010 and 2011, 316 children were enrolled. Viral suppression was achieved in 75.8%, 71.5%, 72.6% and 69.2% at 12, 24, 36 and 48 months. VF occurred in 111/286 (38.8%), of which 67.6% was early and 32.4% late VF. Early VF was associated with a partially active regimen at baseline (OR 6.0, 95% CI 1.9-18.5), poor adherence (OR 3.1, 95% CI 1.3-7.4) and immunodeficiency (OR 3.3, 95% CI 1.1-10.2). Late VF was associated with age >3 years (OR 2.5, 95% CI 1.0-6.6) and WHO stage 3/4 (OR 4.2, 95% CI 1.4-13.4). Acquired DRMs were detected in 27.0% before 24 months, versus 14.4% after 24 months (P < 0.001). A total of 92.2% of the children with early VF, versus 56.2% with late VF, had a partially active regimen (P < 0.001). CONCLUSIONS: VF rates were high, occurred predominantly in the first 24 months and appeared to increase again in year four. Risk factors and patterns of early VF/DRMs were different from those of late VF/DRMs. Virological control may improve by close monitoring and prompt switching to second-line therapy in the first 24 months. Late VF may be prevented by early start of ART.

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.

Daily co-trimoxazole prophylaxis in severely immunosuppressed HIV-infected adults in Africa started on combination antiretroviral therapy: an observational analysis of the DART cohort.

BACKGROUND: Co-trimoxazole prophylaxis can reduce mortality from untreated HIV infection in Africa; whether benefits occur alongside combination antiretroviral therapy (ART) is unclear. We estimated the effect of prophylaxis after ART initiation in adults. METHODS: Participants in our observational analysis were from the DART randomised trial of management strategies in HIV-infected, symptomatic, previously untreated African adults starting triple-drug ART with CD4 counts lower than 200 cells per muL. Co-trimoxazole prophylaxis was not routinely used or randomly allocated, but was variably prescribed by clinicians. We estimated effects on clinical outcomes, CD4 cell count, and body-mass index (BMI) using marginal structural models to adjust for time-dependent confounding by indication. DART was registered, number ISRCTN13968779. FINDINGS: 3179 participants contributed 14 214 years of follow-up (8128 [57%] person-years on co-trimoxazole). Time-dependent predictors of co-trimoxazole use were current CD4 cell count, haemoglobin concentration, BMI, and previous WHO stage 3 or 4 events on ART. Present prophylaxis significantly reduced mortality (odds ratio 0.65, 95% CI 0.50-0.85; p=0.001). Mortality risk reduction on ART was substantial to 12 weeks (0.41, 0.27-0.65), sustained from 12-72 weeks (0.56, 0.37-0.86), but not evident subsequently (0.96, 0.63-1.45; heterogeneity p=0.02). Variation in mortality reduction was not accounted for by time on co-trimoxazole or current CD4 cell count. Prophylaxis reduced frequency of malaria (0.74, 0.63-0.88; p=0.0005), an effect that was maintained with time, but we observed no effect on new WHO stage 4 events (0.86, 0.69-1.07; p=0.17), CD4 cell count (difference vs non-users, -3 cells per muL [-12 to 6]; p=0.50), or BMI (difference vs non-users, -0.04 kg/m(2) [-0.20 to 0.13); p=0.68]. INTERPRETATION: Our results reinforce WHO guidelines and provide strong motivation for provision of co-trimoxazole prophylaxis for at least 72 weeks for all adults starting combination ART in Africa. FUNDING: UK Medical Research Council, the UK Department for International Development, the Rockefeller Foundation, GlaxoSmithKline, Gilead Sciences, Boehringer-Ingelheim, and Abbott Laboratories.

Nevirapine/zidovudine/lamivudine has superior immunological and virological responses not reflected in clinical outcomes in a 48-week randomized comparison with abacavir/zidovudine/lamivudine in HIV-infected Ugandan adults with low CD4 cell counts.

BACKGROUND: Triple nucleoside reverse transcriptase inhibitor regimens have advantages as first-line antiretroviral therapy (ART), avoiding hepatotoxicity and interactions with anti-tuberculosis therapy, and sparing two drug classes for second-line ART. Concerns exist about virological potency; efficacy has not been assessed in Africa. METHODS: A safety trial comparing nevirapine with abacavir was conducted in two Ugandan Development of Antiretroviral Therapy in Africa (DART) centres: 600 symptomatic antiretroviral-naïve HIV-infected adults with CD4 counts <200 cells/microL were randomized to zidovudine/lamivudine plus abacavir or nevirapine (placebo-controlled to 24-week primary toxicity endpoint, and then open-label). Documented World Health Organization (WHO) stage 4 events were independently reviewed and plasma HIV-1 RNA assayed retrospectively. Exploratory efficacy analyses are intention-to-treat. RESULTS: The median pre-ART CD4 count was 99 cells/microL, and the median pre-ART viral load was 284 600 HIV-1 RNA copies/mL. A total of 563 participants (94%) completed 48 weeks of follow-up, 25 (4%) died and 12 (2%) were lost to follow-up. The randomized drug was substituted in 21 participants (7%) receiving abacavir vs. 34 (11%) receiving nevirapine (P=0.09). At 48 weeks, 62% of participants receiving abacavir vs. 77% of those receiving nevirapine had viral loads <50 copies/mL (P<0.001), and mean CD4 count increases from baseline were +147 vs. +173 cells/microL, respectively (P=0.006). Nine participants (3%) receiving abacavir vs. 16 (5%) receiving nevirapine died [hazard ratio (HR) 0.55; 95% confidence interval (CI) 0.24-1.25; P=0.15]; 20 receiving abacavir vs. 32 receiving nevirapine developed new or recurrent WHO 4 events or died (HR=0.60; 95% CI 0.34-1.05; P=0.07) and 48 receiving abacavir vs. 68 receiving nevirapine developed new or recurrent WHO 3 or 4 events or died (HR=0.67; 95% CI 0.46-0.96; P=0.03). Seventy-one participants (24%) receiving abacavir experienced 91 grade 4 adverse events compared with 130 events in 109 participants (36%) on nevirapine (P<0.001). CONCLUSIONS: The clear virological/immunological superiority of nevirapine over abacavir was not reflected in clinical outcomes over 48 weeks. The inability of CD4 cell count/viral load to predict initial clinical treatment efficacy is unexplained and requires further evaluation.

Sexual behaviour among persons living with HIV/AIDS in Kampala, Uganda.

OBJECTIVE: To identify sexual behaviour and reproductive health needs of people living with HIV/AIDS (PLWHAs). DESIGN: A cross sectional study. SETTING: Joint Clinical Research Centre, Kampala Uganda. PARTICIPANTS: Three hundred and eighty PLWHAs, 50% of whom had initiated anti-retro viral therapy (ART). MAIN OUTCOME MEASURES: PLWHAs answered questions regarding sexual behaviour, number and type of sexual partners, symptoms of sexually transmitted infections, having been pregnant or causing a pregnancy, social demographic characteristics, consumption of alcohol, having biological children, desire for more children and use of condoms. RESULTS: In the past 12 months 227 (60%) of the PLWHAs were sexually active. Of the sexually active 42 (19%) never used a condom, and 92 (40%) used condoms inconsistently, thus 134 (35%) of PLWHAs engaged in high risk sex. Two hundred and sixty five (70%) said that PLWHAs can have healthy children and 115 (30%) desired more children with 21 (10%) of the women in the reproductive age group reporting a pregnancy and 22 (17%) of the men reporting having caused a pregnancy. Only three (7%) of the pregnancies were unplanned. Desire for more children was a strong independent predictor of engaging in high risk sex (Adjusted Odds Ratio 2.44, 95% CI 1.35-4.42). CONCLUSIONS: This study demonstrates that abstinence and use of condoms on their own may not be enough for HIV prevention among PLWHAs who desire children. Additional methods such as use of ART to reduce HIV infectiousness and sperm washing are needed.

Routine versus clinically driven laboratory monitoring of HIV antiretroviral therapy in Africa (DART): a randomised non-inferiority trial.

BACKGROUND: HIV antiretroviral therapy (ART) is often managed without routine laboratory monitoring in Africa; however, the effect of this approach is unknown. This trial investigated whether routine toxicity and efficacy monitoring of HIV-infected patients receiving ART had an important long-term effect on clinical outcomes in Africa. METHODS: In this open, non-inferiority trial in three centres in Uganda and one in Zimbabwe, 3321 symptomatic, ART-naive, HIV-infected adults with CD4 counts less than 200 cells per microL starting ART were randomly assigned to laboratory and clinical monitoring (LCM; n=1659) or clinically driven monitoring (CDM; n=1662) by a computer-generated list. Haematology, biochemistry, and CD4-cell counts were done every 12 weeks. In the LCM group, results were available to clinicians; in the CDM group, results (apart from CD4-cell count) could be requested if clinically indicated and grade 4 toxicities were available. Participants switched to second-line ART after new or recurrent WHO stage 4 events in both groups, or CD4 count less than 100 cells per microL (LCM only). Co-primary endpoints were new WHO stage 4 HIV events or death, and serious adverse events. Non-inferiority was defined as the upper 95% confidence limit for the hazard ratio (HR) for new WHO stage 4 events or death being no greater than 1.18. Analyses were by intention to treat. This study is registered, number ISRCTN13968779. FINDINGS: Two participants assigned to CDM and three to LCM were excluded from analyses. 5-year survival was 87% (95% CI 85-88) in the CDM group and 90% (88-91) in the LCM group, and 122 (7%) and 112 (7%) participants, respectively, were lost to follow-up over median 4.9 years' follow-up. 459 (28%) participants receiving CDM versus 356 (21%) LCM had a new WHO stage 4 event or died (6.94 [95% CI 6.33-7.60] vs 5.24 [4.72-5.81] per 100 person-years; absolute difference 1.70 per 100 person-years [0.87-2.54]; HR 1.31 [1.14-1.51]; p=0.0001). Differences in disease progression occurred from the third year on ART, whereas higher rates of switch to second-line treatment occurred in LCM from the second year. 283 (17%) participants receiving CDM versus 260 (16%) LCM had a new serious adverse event (HR 1.12 [0.94-1.32]; p=0.19), with anaemia the most common (76 vs 61 cases). INTERPRETATION: ART can be delivered safely without routine laboratory monitoring for toxic effects, but differences in disease progression suggest a role for monitoring of CD4-cell count from the second year of ART to guide the switch to second-line treatment. FUNDING: UK Medical Research Council, the UK Department for International Development, the Rockefeller Foundation, GlaxoSmithKline, Gilead Sciences, Boehringer-Ingelheim, and Abbott Laboratories.

Widow inheritance and HIV/AIDS in rural Uganda.

Despite current efforts to combat HIV/AIDS through behavioural change, ingrained socio-cultural practices such as widow inheritance in south-western Uganda has not changed. Low education, unemployment, dowry, widows' socioeconomic demands and the inheritor's greed for the deceased's wealth, influence widow inheritance. Voluntary counselling and testing is needed for the widows and their inheritors; formal dowry should be removed from marriage and widow inheritance stripped of its sexual component.

Cytochrome P450 2B6 (CYP2B6) G516T influences nevirapine plasma concentrations in HIV-infected patients in Uganda.

OBJECTIVES: Polymorphisms in the cytochrome P450 (CYP) 2B6 gene have been shown to influence nevirapine plasma concentrations in HIV-infected European Caucasians. Although nevirapine is used extensively in Africa, the influence of CYP2B6 genotype on nevirapine exposure has not been assessed in this population. We aimed to determine the influence of CYP2B6 genotype at position 516 on nevirapine trough concentrations in HIV-infected patients in Kampala, Uganda. Additional polymorphisms in the CYP and multidrug resistance protein-1 (MDR-1) genes were also assessed for their impact on nevirapine concentrations. METHODS: The following genotypes were determined in all subjects using polymerase chain reaction-restriction fragment length polymorphism: CYP2B6 G516T, MDR-1 C3435T and G2677T, CYP3A4(*)1B and CYP3A5(*)3. Nevirapine plasma concentrations were determined using high-performance liquid chromatography in 23 HIV-infected patients who were generally healthy and had been taking nevirapine 200 mg twice daily for at least 14 days. Analysis of variance with post hoc testing was used to compare nevirapine concentrations among CYP2B6 genotype groups. RESULTS: The median nevirapine trough concentration in individuals homozygous for the variant allele (TT) was 7607 ng/mL vs 4181 and 5559 ng/mL for GG and GT individuals, respectively (GG vs TT median ratio=1.82; P=0.011). The mean ratio for TT vs GG individuals (95% confidence interval) was 1.51 (1.18, 1.84). No associations were observed between the other polymorphisms studied and nevirapine concentrations. CONCLUSIONS: CYP2B6 G516T significantly influenced nevirapine trough concentrations in HIV-infected patients in Uganda. Additional studies in larger patient populations are necessary to further define the potential clinical impact of these preliminary findings.

Adherence to HIV antiretroviral therapy in HIV+ Ugandan patients purchasing therapy.

Our objective was to determine the level of adherence and reasons for non-adherence to antiretroviral therapy (ART) among HIV-positive (HIV+) people on ART in a resource-limited setting. Patients receiving ART were recruited into the cross-sectional study from three treatment centres in Kampala, Uganda. The number of missed doses over the last three days was assessed by structured patient interviews and dichotomized at +/-95% adherence. Reasons for non-adherence were assessed with both structured patient interviews and unstructured qualitative interviews. Independent predictors of non-adherence were assessed with multivariate logistic regression. In all, 304 HIV-infected persons on ART were enrolled into the study. Factors associated with non-adherence were marital status (odds ratio (OR) = 2.93, 95% confidence interval (CI) 1.32-6.50) and low monthly income <50 US$ [OR = 2.77, 95% CI 1.64-4.67]. We concluded that levels of self-reported adherence in patients receiving ART in Kampala are comparable to levels in resource-rich settings with inability to purchase and secure a stable supply as a major barrier to adherence.

Immunogenicity of a recombinant human immunodeficiency virus (HIV)-canarypox vaccine in HIV-seronegative Ugandan volunteers: results of the HIV Network for Prevention Trials 007 Vaccine Study.

In the first preventative human immunodeficiency virus (HIV) vaccine study to be carried out in Africa, 40 HIV-seronegative Ugandan volunteers were randomly assigned to receive a canarypox vector containing HIV-1 clade B (env and gag-pro) antigens (ALVAC-HIV; n = 20), control vector containing the rabies virus glycoprotein G gene (n = 10), or saline placebo (n = 10). Cytotoxic T lymphocyte activity against target cells expressing clade A, B, and D antigens was assessed using standard chromium-release and confirmatory interferon-gamma enzyme-linked immunospot (ELISPOT) assays. Neutralizing antibody responses to cell line-adapted strains and primary isolates in all 3 clades were also tested. Twenty percent of vaccine recipients generated detectable cytolytic responses to either Gag or Env, and 45% had vaccine-induced HIV-specific CD8(+) T cell responses, as measured by the ELISPOT assay. In contrast, only 5% of the control group had vaccine-specific responses. Neutralizing antibodies against primary and laboratory-adapted HIV-1 clade B strains were seen in 10% and 15% of vaccine recipients, respectively, but responses against clades A and D were not detected. Although the immunogenicity of this clade B-based vaccine was low, ALVAC-HIV elicited CD8(+) T cell responses with detectable cross-activity against clade A and D antigens in a significant proportion of vaccine recipients.

Increased replication of HIV-1 at sites of Mycobacterium tuberculosis infection: potential mechanisms of viral activation.

Tuberculosis (TB) enhances HIV-1 replication and the progression to AIDS in dually infected patients. We employed pleural TB as a model to understand the interaction of the host with HIV-1 during active TB, at sites of Mycobacterium tuberculosis (MTB) infection. HIV-1 replication was enhanced both in the cellular (pleural compared with blood mononuclear cells) and acellular (pleural fluid compared with plasma) compartments of the pleural space. Several potential mechanisms for expansion of HIV-1 in situ were found, including augmentation in expression of tumor necrosis factor (TNF)-alpha and the HIV-1 noninhibitory beta-chemokine (MCP-1), low presence of HIV-1 inhibitory beta-chemokines (MIP-1 alpha, MIP-1 beta, and RANTES [regulated on activation, normal T expressed and secreted]), and upregulation in expression of the HIV-1 coreceptor, CCR5, by pleural fluid mononuclear cells. Thus, at sites of MTB infection, conditions are propitious both for transcriptional activation of HIV-1 in latently infected mononuclear cells, and facilitation of viral infection of newly recruited cells. These mechanisms may contribute to enhanced viral burden and dissemination during TB infection.

Duration of efficacy of treatment of latent tuberculosis infection in HIV-infected adults.

BACKGROUND: Treatment of latent infection is needed to protect HIV-infected individuals against tuberculosis. A previous report addressed short-term efficacy of three regimens in HIV-infected adults. We now report on long-term efficacy of the study regimens. METHODS: Three daily self-administered regimens were compared in a randomized placebo-controlled trial in 2736 purified protein derivative (PPD)-positive and anergic HIV-infected adults. PPD-positive subjects were treated with isoniazid (INH) for 6 months (6H), INH plus rifampicin for 3 months (3HR), INH plus rifampicin and pyrazinamide for 3 months (3HRZ), or placebo for 6 months. Anergic subjects were randomized to 6H or placebo. RESULTS: 6H initially protected against tuberculosis in PPD-positive individuals; however, benefit was lost within the first year of treatment. Sustained benefit was observed in persons receiving 3HR and 3HRZ. In a Cox regression analysis, the adjusted relative risk for tuberculosis compared with placebo was 0.67 [95% confidence interval (CI), 0.42-1.07] for 6H, 0.49 (95% CI, 0.29-0.82) for 3HR, and 0.41 (95% CI, 0.22-0.76) for 3HRZ. When the rifampicin-containing regimens were combined, the adjusted relative risk for tuberculosis compared with placebo was 0.46 (95% CI, 0.29-0.71). Among anergic subjects, a modest degree of protection with 6H was present (adjusted relative risk, 0.61; 95% CI, 0.32-1.16). Treatment of latent tuberculosis infection had no effect on mortality. CONCLUSION: Six months of INH provided short-term protection against tuberculosis in PPD-positive HIV-infected adults. Three month regimens including INH plus rifampicin or INH, rifampicin and pyrazinamide provided sustained protection for up to 3 years.

Resistance to antiretroviral therapy among patients in Uganda.

OBJECTIVE: To characterize HIV-1 phenotypic resistance patterns and genotypic mutations among patients taking antiretroviral medications in Uganda. METHODS: We reviewed charts and retrieved archived plasma specimens from patients at an AIDS specialty center in Uganda where antiretroviral therapy has been used since 1996. Phenotypic and genotypic resistance testing was done on specimens associated with a viral load of 1000 copies/ml. RESULTS: Resistance testing of specimens was completed for 16 patients. Among 11 specimens collected before initiation of antiretroviral therapy, no phenotypic resistance or primary genotypic mutations were found. Among 8 patients taking lamivudine, phenotypic resistance was found for 9 (90%) of 10 specimens and was associated with an M184V mutation in all nine cases. Among 12 patients taking zidovudine, no phenotypic resistance and few primary mutations were found. For 6 patients who were receiving protease inhibitors, we observed no phenotypic resistance and only one primary genotypic mutation associated with resistance. CONCLUSIONS: The absence of apparent resistance among samples collected before antiretroviral therapy supports the notion that a similar approach to selection of antiretroviral therapy can generally be used against non-B subtypes. A genotypic marker of antiretroviral resistance to lamivudine in HIV-1 subtypes A, C, and D was similar to those in subtype B infections. These results suggest that the methods used for monitoring for the emergence of drug resistance in antiretroviral programs in Africa may be similar to those used in developed settings.

Impact of tuberculosis (TB) on HIV-1 activity in dually infected patients.

Active TB in HIV-1-infected subjects is associated with increased HIV-1-related immunodeficiency and mortality. We assessed plasma viral load in HIV-1-infected patients with pulmonary TB (HIV/TB) and non-TB symptomatic HIV-1-infected patients (HIV). HIV-1 load was higher in HIV/TB compared with HIV at higher CD4 counts (> 500/microl) (P < 0.01), but not at lower CD4 counts (< 500/microl). We also evaluated the status of HIV-1 gene expression in peripheral blood mononuclear cells (PBMC) and serum from HIV/TB and CD4-matched healthy HIV-infected patients (HIV/C) by reverse transcriptase-polymerase chain reaction over a range of CD4 (> 900/microl to < 200/microl). HIV-1 RNA in serum and PBMC correlated to one another, and both were markedly higher in HIV/TB compared with HIV/C with higher CD4 counts. Also, during a longitudinal study of anti-tuberculous chemoprophylaxis in HIV-1-infected patients, 10 subjects who developed TB had serologies before, at the time, and after the diagnosis of TB. These HIV/TB patients had an increase in viral load (average 2.5-fold) at the time of diagnosis of TB (P < 0.05). Overall, these data indicate that the transcriptional activity of HIV-1 is enhanced in HIV-1-infected patients with active TB, especially during early HIV-1 disease. As TB often is an early HIV-1 opportunistic infection, it may particularly favour early viral replication and dissemination, and therefore contribute to progression of HIV-1 disease.

Augmentation of apoptosis and interferon-gamma production at sites of active Mycobacterium tuberculosis infection in human tuberculosis.

Pleural tuberculosis (TB) was employed as a model to study T cell apoptosis at sites of active Mycobacterium tuberculosis (MTB) infection in human immunodeficiency virus (HIV)-coinfected (HIV/TB) patients and patients infected with TB alone. Apoptosis in blood and in pleural fluid mononuclear cells and cytokine immunoreactivities in plasma and in pleural fluid were evaluated. T cells were expanded at the site of MTB infection, irrespective of HIV status. Apoptosis of CD4 and non-CD4 T cells in the pleural space occurred in both HIV/TB and TB. Interferon (IFN)-gamma levels were increased in pleural fluid, compared with plasma. Spontaneous apoptosis correlated with specific loss of MTB-reactive, IFN-gamma-producing pleural T cells. Immunoreactivities of molecules potentially involved in apoptosis, such as tumor necrosis factor-alpha, Fas-ligand, and Fas, were increased in pleural fluid, compared with plasma. These data suggest that continued exposure of immunoreactive cells to MTB at sites of infection may initiate a vicious cycle in which immune activation and loss of antigen-responsive T cells occur concomitantly, thus favoring persistence of MTB infection.

T cell activation, apoptosis and cytokine dysregulation in the (co)pathogenesis of HIV and pulmonary tuberculosis (TB).

Immune parameters were compared in four groups of Ugandan subjects: HIV-and HIV+ adult patients with active pulmonary TB (HIV- PTB n = 38; HIV+ PTB n = 28), patients with HIV infection only (n = 26) and PPD+ healthy controls (n = 25). Compared with healthy controls, CD4 and CD8 T cells from patients with HIV and/or PTB expressed more activation markers (HLA-DR, CD38); their CD8 T cells expressed more CD95 (pre-apoptosis) and less CD28 (co-stimulatory receptor). Peripheral blood mononuclear cells (PBMC) of patients with either HIV or PTB were impaired in interferon-gamma (IFN-gamma) production upon antigenic stimulation. PTB (with or without HIV) was characterized by monocytosis, granulocytosis, increased transforming growth factor-beta 1 production and PPD-induced apoptosis. In vivo CD4 T cell depletion, in vitro increased spontaneous CD4 T cell apoptosis and defects in IFN-gamma responses upon mitogenic stimulation were restricted to HIV+ subjects (with or without PTB). Overlapping and distinctive immune alterations, associated with PTB and HIV, might explain mutual unfavourable influences of both diseases.

Cellular immunity to human immunodeficiency virus type 1 (HIV-1) clades: relevance to HIV-1 vaccine trials in Uganda.

The first prophylactic human immunodeficiency virus type 1 (HIV-1) vaccine trial in Africa, with a clade B immunogen, is currently under way in Uganda, in a region where clades A and D are endemic. The use of a B clade vaccine is based on anticipated cross-recognition of endemic strains of HIV-1 in Uganda, but, in fact, little is known about the cytotoxic T lymphocyte (CTL) responses in that region. Seventeen HIV-1-infected volunteers from Kampala, Uganda, were studied to determine the immune responses elicited by natural infection with local HIV-1 strains. Despite the presence of broad cross-clade recognition, the CTL responses to the infecting viral clade were highest in most people. Recognition of nonendemic clade B antigens was similar to that of the coendemic local clade, and, in some instances, cross-recognition of clade B was greater. Nevertheless, the degree of cross-clade cellular responses we observed lends justification to the use of clade B-based immunogens in the current phase 1 vaccine trial in Uganda.

Expression of chemokine receptors on CD4+ T cells in peripheral blood from HIV-infected individuals in Uganda.

CXCR4, a coreceptor for T cell (T)-tropic HIV-1, is preferentially expressed on naive T cells, whereas CCR5, a coreceptor for macrophage (M)-tropic HIV-1, is preferentially expressed on previously activated memory T cells and the Th1 subset of CD4+ T cells. CCR4 is preferentially expressed on the Th2 subset of CD4+ T cells. A cross-sectional flow cytometry study was conducted to evaluate the expression of CXCR4, CCR5, and CCR4 on the peripheral blood CD4+ T cells from African HIV-1-infected and uninfected Ugandan adults. The plasma viral load in HIV-1-infected individuals was also examined. Upregulation of CCR4 and CCR5 expression but no decrease in CXCR4 expression on CD4+ T cells were obtained in peripheral blood from African adults with progression of the disease. Plasma HIV-1 viremia significantly and inversely correlated with the peripheral CD4+ T cell count but did not correlate with the degree of CCR4 and CCR5 expression on the peripheral CD4+ T cells in HIV-1-infected individuals. Our present data suggest an increase in percentage of activated memory CD4+ T cells in the advanced stage of HIV-1 infection among African adults. There was no evidence of a Th1 to Th2 shift in terms of chemokine receptor expression profile with advancing disease in the peripheral blood of these subjects.

Apoptosis and T cell hyporesponsiveness in pulmonary tuberculosis.

Mycobacterium tuberculosis (MTB)-induced T cell responses are depressed in peripheral blood mononuclear cells of persons with newly diagnosed pulmonary tuberculosis (TB), and levels of interferon (IFN)-gamma remain low even after completion of antituberculous therapy. Loss of MTB-reactive T cells through apoptotic mechanisms could account for this prolonged T cell hyporesponsiveness. T cell apoptosis was studied in TB patients and healthy control subjects. Both spontaneous and MTB-induced apoptosis (in CD4 and non-CD4 T cells) from TB patients was increased when compared with healthy control subjects, whereas coculture with control antigen (candida) had no effect on T cell apoptosis in either group of study subjects. An inverse correlation existed between increased MTB-induced T cell apoptosis and IFN-gamma and interleukin (IL)-2 immunoreactivities. Successful antituberculous chemotherapy resulted in a 50% reduction in both spontaneous and MTB-induced apoptosis, which coincided with 3- and 8-fold increases in levels of MTB-stimulated IL-2 and IFN-gamma, respectively. These data indicate that apoptotic pathways are operant during active MTB infection and may contribute to deletion of MTB-reactive T cells and the immunopathogenesis of this disease.

Instability of tuberculin and Candida skin test reactivity in HIV-infected Ugandans. The Uganda-Case Western Reserve University Research Collaboration.

Anergy testing has been used as an adjunct to tuberculin testing for assessing M. tuberculosis (MTB) infection and indications for isoniazid preventive therapy in HIV-infected persons. We examined factors associated with the stability of skin test responses to purified protein derivative (PPD) and candida antigens in a cohort of HIV-infected adults followed prospectively in a tuberculosis preventive therapy trial in Uganda. PPD-positive and anergic subjects in the placebo arms of the preventive therapy study underwent repeat skin testing and immunologic testing including measurement of MTB culture filtrate (CF)-stimulated interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) levels in whole-blood culture supernatants. Anergy was present in 27% of 4,058 HIV-infected subjects screened for the tuberculosis preventive therapy trial compared with 10% of 682 HIV-non-infected persons. On follow-up testing of enrolled subjects, 42% of 139 initially anergic subjects were no longer anergic; two thirds of these had PPD reactions >= 5 mm. Stability of anergy was associated with intercurrent opportunistic infections and AIDS-associated dermatitis at baseline. Thirty-five percent of 313 subjects with an initial positive PPD had a negative PPD test at follow-up, 26% of whom had a positive candida skin test at the same time as the negative PPD test. Baseline MTBCF-stimulated IFN-gamma levels were significantly higher among PPD-positive subjects who remained PPD-positive than in those who were falsely negative. We conclude first that anergy is unstable and second that anergy testing is unreliable in identifying HIV-infected adults who are not infected with MTB and should not be used routinely for this purpose in assessing indications for isoniazid preventive therapy.