Immune reconstitution in HIV-1 infected subjects treated with potent antiretroviral therapy

Pathophysiology and Clinical Management of Dyslipidemia in People Living with HIV: Sailing through Rough Seas

Infections with human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) represent one of the greatest health burdens worldwide. The complex pathophysiological pathways that link highly active antiretroviral therapy (HAART) and HIV infection per se with dyslipidemia make the management of lipid disorders and the subsequent increase in cardiovascular risk essential for the treatment of people living with HIV (PLHIV). Amongst HAART regimens, darunavir and atazanavir, tenofovir disoproxil fumarate, nevirapine, rilpivirine, and especially integrase inhibitors have demonstrated the most favorable lipid profile, emerging as sustainable options in HAART substitution. To this day, statins remain the cornerstone pharmacotherapy for dyslipidemia in PLHIV, although important drug-drug interactions with different HAART agents should be taken into account upon treatment initiation. For those intolerant or not meeting therapeutic goals, the addition of ezetimibe, PCSK9, bempedoic acid, fibrates, or fish oils should also be considered. This review summarizes the current literature on the multifactorial etiology and intricate pathophysiology of hyperlipidemia in PLHIV, with an emphasis on the role of different HAART agents, while also providing valuable insights into potential switching strategies and therapeutic options.

Quantification of CD4 Recovery in Early-Treated Infants Living With HIV

BACKGROUND

Perinatally HIV-acquired infants benefit from an early antiretroviral treatment initiation. Thanks to a short viral exposure time, their immune system can be maintained or reconstituted, allowing a "normal" immune development.

METHODS

In this study, we mathematically modeled and quantified individual CD4+ T-cell reconstitution of a subset of 276 children who started treatment within 6 months of age and achieved sustained viral suppression. Considering natural age differences in CD4+ T-cell dynamics, we fitted distances to age-matched healthy reference values with a linear model approaching an asymptote.

RESULTS

Depleted CD4+ percentages (CD4%) and CD4+ counts (CD4ct) restored healthy levels during treatment. CD4ct recovered with a median rate of 4 cells/µL/d, and individual recovery rates were correlated negatively with their initial CD4ct. CD4 values at onset of treatment decrease with age, whereas recovery times and levels seem to be age-independent. CD4 recovery correlates positively with viral suppression, and the stabilization of CD4 levels usually occurs after viral suppression. CD4 levels stabilize within 3-13 months after treatment initiation. The recovery dynamics of the CD4% is comparable with those of the CD4ct.

CONCLUSIONS

In early-treated children with successful viral suppression, the CD4 depletion is typically mild and CD4+ T cells tend to "fully" recover in numbers.

The far-reaching HAND of cART: cART effects on astrocytes

Following the introduction of combination antiretroviral therapy (cART), the morbidity and mortality from human immunodeficiency virus (HIV) infection has been drastically curtailed and HIV has now become a chronic manageable disease. Persons living with HIV (PLWH) are living longer and experiencing significant co-morbidities and conditions of aging. NeuroHIV, clinically defined as HIV-Associated Neurocognitive Disorders (HAND) and pathologically manifested by persistent inflammation in the CNS despite cART, is a significant co-morbid condition for PLWH. In the pre-cART era, HIV mediated much of the pathogenesis in the Central Nervous System (CNS); in the cART era, with low to undetectable viremia, other mechanisms may be contributing to persistent neuroinflammation. Emerging data point to the adverse effects at the cellular level of cART, independent of HIV. Astrocytes are the most abundant cells in the CNS, playing vital roles in maintaining CNS homeostasis (e.g. metabolic support to neurons, clearance of neurotransmitters, ion balance, modulation of synaptic functions and maintaining the structural integrity of the blood brain barrier (BBB). Therefore, any disruption of their function will have wide repercussions in the CNS. In this review, we will address current knowledge and gaps on the impact of antiretrovirals (ARVs) on astrocytes and physiologic consequences in the CNS. Understanding the status of this field, will provide a practical framework to elucidate the potential role of cART-mediated dysregulation of astrocytes in neuroHIV pathogenesis and inform therapeutic strategies that are "neuro-friendly". Graphical abstract CNS-penetrating cART have the potential to cause resting astrocytes to become activated into an A1 or neurotoxic phenotype. These cells can in turn secrete inflammatory cytokines that affect surrounding microglia macrophages, as well as neurotoxic factors that impact nearby neurons. In addition, impairment in the physiologic functions of astrocytes will result in altered BBB permeability and disrupted metabolic homeostasis. CNS=Central Nervous System; cART=combined antiretroviral therapy; BBB=blood brain barrier.

Reduced IL-7R T Cell Expression and Increased Plasma sCD127 in Late Presenting HIV-Infected Individuals

BACKGROUND

Late presentation of HIV infection is associated with reduced chance of optimal immune recovery after initiating combination antiretroviral therapy (cART). Interleukin-7 (IL-7) and the corresponding receptor, IL-7 receptor (IL-7R) made up of CD127 and CD132, are crucial for T cell homeostasis. This study aimed to describe IL-7R and IL-7 before and after initiation of cART in late presenting HIV-infected individuals, and the impact on immune recovery and T cell subset distribution after initiation of cART.

METHODS

A total of 100 HIV-infected individuals initiating cART were included in a prospective study. Samples were collected at baseline and after 6, 12, and 24 months of cART. Proportion and expression {[median fluorescence intensity (MFI)]} of IL-7R on T cells, and plasma concentrations of soluble CD127 (sCD127) and IL-7 were determined.

RESULTS

The IL-7R expression was reduced in late presenters with CD4 cell count <200 cells per microliter compared with nonlate presenters and healthy controls as demonstrated by lower proportion of CD127 + CD132 + T cells and lower CD127 MFI. In contrast, plasma sCD127 was higher. These differences were partly reversed after suppressive cART. Interestingly, the CD127 MFI on CD4 T cells was found to be a predictor of increased thymic output after 24 months of suppressive cART.

CONCLUSIONS

Severely altered IL-7R expression was found in late presenters, and associations between IL-7R expression and thymic output after 24 months of suppressive cART indicate an impact of a IL-7 response for the long term de novo production from thymus.

Effectiveness of first-line antiretroviral therapy in HIV/AIDS patients: A 5-year longitudinal evaluation in Fujian Province, Southeast China

The aim of this study was to evaluate the long-term effectiveness of first-line antiretroviral therapy in HIV/AIDS patients in Southeast China. A total of 450 eligible patients were selected to initiate first-line antiretroviral therapy from February 2005 through August 2009. During the study period from 2009 through 2013, each subject received clinical and laboratory monitoring for effectiveness, safety and toxicity once every 3 months in the first year, and once every 6 months in the following years. The response to first-line antiretroviral therapy was evaluated through body weight gain and immunological and virological outcomes. During the mean follow-up period of 70.86 ± 28.9 months, the overall mortality was 14.2%. The mean body weight and CD4(+) counts increased significantly following antiretroviral therapy as compared to baselines across the follow-up period, and the rate of immunological effectiveness was over 85% in all subjects at 2 to 5 years of treatment. The rate of inhibition of HIV virus was 87.67%, 89.32%, 91.73%, 92.8% and 91.63% across the study period. In addition, significant differences were detected after treatment as compared to baselines, and Pearson correlation analysis revealed a positive correlation between immunological effectiveness and viral inhibition. Forty-eight percent of the subjects changed antiretroviral drugs once, and 16.22% twice, and 31 patients switched from first-line to second-line antiretroviral therapy. Long-term antiretroviral therapy remains effective for treatment of HIV/AIDS, resulting in higher mean body weight, effective viral inhibition and a higher CD4 count. Immunological effectiveness of antiretroviral therapy positively correlates with HIV viral inhibition.

Incidence, spectrum and outcome of immune reconstitution syndrome in HIV-infected children after initiation of antiretroviral therapy

BACKGROUND

Immune reconstitution syndrome (IRS) is a relatively common complication in HIV-infected adults starting combination antiretroviral therapy (cART). Data on IRS in HIV-infected children remain limited and are largely restricted to resource-limited settings. This study investigated the incidence, spectrum and outcome of IRS in a pediatric cohort in the United Kingdom.

METHODS

Retrospective analysis of clinical events during the first 12 months after initiation of cART in 135 treatment-naïve, HIV-infected children in the United Kingdom over a 5-year period. Demographic and laboratory data were provided by the Collaborative HIV Paediatric Study.

RESULTS

The median age at cART initiation was 6.6 years (interquartile range: 2.3-10.2). The median CD4 lymphocyte percentage (CD4%) at baseline was 15% (median CD4 lymphocyte count: 390 cells/μL). Eight patients (5.9%) developed IRS (incidence: 5.7/100 person years). The IRS events comprised: Bacillus Calmette-Guerin-related complications (local ulceration/lymphadenitis; n = 4), pulmonary tuberculosis (n = 1), Mycobacterium avium intracellulare infection (n = 1), combined tuberculosis/Mycobacterium avium intracellulare infection (n = 1) and cutaneous herpes simplex (n = 1). The mortality was significantly higher in children with IRS than in those without (P < 0.0001). The only statistically significant risk factor for IRS identified was increment in CD4 count at 12 months after starting cART (P = 0.03).

CONCLUSIONS

The incidence of IRS was significantly lower than previously reported from resource-limited settings, likely reflecting less profound immunodeficiency at cART initiation and fewer coexisting opportunistic infections in our cohort. However, IRS events were associated with considerable morbidity and mortality. Therefore, preventive strategies that can reduce the risk of IRS in children need to be identified.

Polymorphism in interleukin-7 receptor α gene is associated with faster CD4⁺ T-cell recovery after initiation of combination antiretroviral therapy

OBJECTIVES

To investigate single-nucleotide polymorphisms (SNPs) in the gene encoding interleukin-7 receptor α (IL7RA) as predictors for CD4⁺ T-cell change after initiation of combination antiretroviral therapy (cART) in HIV-infected whites.

DESIGN

SNPs in IL7RA were determined in the Danish HIV Cohort Study.

METHODS

CD4⁺ T-cell changes were estimated 6 months, 1, 2, and 5 years after initiation of cART in 1683 HIV-infected virally suppressed individuals. Five SNPs in IL7RA were examined as predictors for CD4⁺ T-cell change in the first (0-6 months after initiation of cART) and second phase (>6 months after initiation of cART) of immune recovery. Univariable and multivariable analyses including age, sex, calendar period, CD4⁺ nadir, and baseline CD4⁺ T-cell count and viral load as covariates were performed.

RESULTS

Individuals carrying two T-alleles in rs6897932 had faster CD4⁺ T-cell recovery compared with individuals carrying a C-allele in the first phase of immune recovery [mean CD4⁺ T-cell change, cells/μL (95% confidence interval), in TT: 177 (151-203), CT: 131 (119-143), CC: 141 (132-151), P = 0.018]. No isolated effect of rs6897932 on CD4⁺ T-cell change was found in the second phase of immune recovery; however, the initial difference in CD4⁺ T-cell recovery remained during 5 years. The effect was most pronounced in individuals above 40 years of age.

CONCLUSION

T-allele homozygosity in rs6897932 is a predictor for faster CD4⁺ T-cell recovery after initiation of cART in HIV-infected whites, however, only in the first phase of immune recovery.

Emerging trends of HIV drug resistance in Chinese HIV-infected patients receiving first-line highly active antiretroviral therapy: a systematic review and meta-analysis

BACKGROUND

Highly active antiretroviral therapy (HAART) has led to a dramatic decrease in AIDS-related morbidity and mortality through sustained suppression of human immunodeficiency virus (HIV) replication and reconstitution of the immune response. Settings like China that experienced rapid HAART rollout and relatively limited drug selection face considerable challenges in controlling HIV drug resistance (DR).

METHODS

We conducted a systematic review and meta-analysis to describe trends in emergent HIV DR to first-line HAART among Chinese HIV-infected patients, as reflected in the point prevalence of HIV DR at key points and fixed intervals after treatment initiation, using data from cohort studies and cross-sectional studies respectively.

RESULTS

Pooled prevalence of HIV DR from longitudinal cohorts studies was 10.79% (95% confidence interval [CI], 5.85%-19.07%) after 12 months of HAART and 80.58% (95% CI, 76.6%-84.02%) after 72 months of HAART. The HIV DR prevalence from cross-sectional studies was measured in treatment intervals; during the 0-12-month HAART treatment interval, the pooled prevalence of HIV DR was 11.1% (95% CI, 7.49%-16.14%), which increased to 22.92% at 61-72 months (95% CI, 9.45%-45.86%). Stratified analyses showed that patients receiving a didanosine-based regimen had higher HIV DR prevalence than those not taking didanosine (15.82% vs 4.97%). Patients infected through former plasma donation and those receiving AIDS treatment at village clinics had higher HIV DR prevalence than those infected through sexual transmission or treated at a county-level hospital.

CONCLUSIONS

Our findings indicate higher prevalence of HIV DR for patients with longer cumulative HAART exposure, highlighting important subgroups for future HIV DR surveillance and control.

Association of HIV clinical disease progression with profiles of early immune activation: results from a cluster analysis approach

OBJECTIVE

CD4 and CD8 T-cell activation are independent predictors of AIDS. The complete activation profile of both T-cell subtypes and their predictive value for AIDS risk is largely unknown.

DESIGN

A total of 564 AIDS-free women in the Women's Interagency HIV Study were followed over 6.1 years (median) after T-cell activation assessment. A cluster analysis approach was used to evaluate the concurrent activation patterns of CD4 and CD8 T cells at the beginning of follow-up in relation to AIDS progression.

METHODS

Percentages of CD4 and CD8 T cells with HLA-DR± and CD38± were assessed by flowcytometry. Eight immunologic variables (four on each CD4+ and CD8+: DR± and CD38±) were assessed to yield a 4-cluster solution on samples obtained before clinical endpoints. Proportional hazards survival regression estimated relative risks for AIDS progression by cluster membership.

RESULTS

Compared with the other three clusters, outstanding activation features of each distinct cluster of women were: Cluster 1: higher CD8(+)CD38(-)DR(-) (average=41% of total CD8 T-cell pool), CD4(+)CD38(-)DR(-) (average=53% of total CD4 T-cell pool), and CD8(+)CD38(-)DR(+) (28%); Cluster 2: higher CD8(+)CD38(+)DR(-) (44%) and CD4(+)CD38(+)DR(-) (58%); Cluster 3: higher CD8(+)CD38(+)DR(+) (49%) and CD4(+)CD38(+)DR(-) (48%); Cluster 4: higher CD8(+)CD38(+)DR(+) (49%), CD4(+)CD38(+)DR(+) (36%) and CD4(+)CD38(-)DR(+) (19%). Compared with cluster 1, women in cluster 4 had two-fold increased risk of AIDS progression (Hazard ratio=2.13; 95% confidence interval=1.30-3.50) adjusted for CD4 cell count, HIV RNA, and other confounders.

CONCLUSION

A profile including CD4 and CD8 T-cell activation provided insight into HIV pathogenesis indicating concurrent hyperactivation of CD4 and CD8 T cells is associated with AIDS progression.

[Host's genetics in HIV disease]

In the 1990 s, the variability of responses to human immunodeficiency virus (HIV) could only be tracked by phenotypic criteria such as the number of CD4T lymphocytes, the occurrence of opportunistic infection, the disease free survival without treatment. In 1996, the viral load is the leading phenotype for genetic studies. Ever since, thanks to a better understanding of the HIV infection pathophysiology, numerous studies helped to highlight the influence of genetic variability on inter-individual response to this virus. Among the genes having an impact, we can quote the following examples: CCR5, HLA-B and HLA-C genes. Practical applications of genetics in clinical medicine include search for HLA-B*57:01 before abacavir introduction. Recently, an eradicating treatment for HIV disease after bone marrow transplantation with a donor homozygote for a CCR5 gene non-functional variant (CCR5Δ32) has been reported. Interest in genetics of chronic viral infection is not specific to HIV. It has also been used on other viral diseases and it has gained a major place on the management of diseases.

HIV-1 induced bystander apoptosis

Apoptosis of uninfected bystander cells is a key element of HIV pathogenesis and believed to be the driving force behind the selective depletion of CD4+ T cells leading to immunodeficiency. While several viral proteins have been implicated in this process the complex interaction between Env glycoprotein expressed on the surface of infected cells and the receptor and co-receptor expressing bystander cells has been proposed as a major mechanism. HIV-1 utilizes CD4 as the primary receptor for entry into cells; however, it is the viral co-receptor usage that greatly influences CD4 decline and progression to AIDS. This phenomenon is relatively simple for X4 viruses, which arise later during the course of the disease, are considered to be highly fusogenic, and cause a rapid CD4+ T cell decline. However, in contrast, R5 viruses in general have a greater transmissibility, are encountered early during the disease and have a lesser pathogenic potential than the former. The above generalization gets complicated in numerous situations where R5 viruses persist throughout the disease and are capable of causing a rigorous CD4+ T cell decline. This review will discuss the multiple factors that are reported to influence HIV induced bystander apoptosis and pathogenesis including Env glycoprotein phenotype, virus tropism, disease stage, co-receptor expression on CD4+ T cells, immune activation and therapies targeting the viral envelope.

Central memory CD4 cells are an early indicator of immune reconstitution in HIV/AIDS patients with anti-retroviral treatment

The number of central memory cells among the CD4+ T cells and the of activation of CD8+ T cells is believed to be a better indicator of immune restoration in patients on antiretroviral therapy (ART) than the absolute numbers of CD4(+) and CD8+ T cells alone. In the current study, we investigated the changes in the CD4(+) T cell subsets and their association with immune reconstitution and immune activation at early stages of ART. A prospective study was performed in 21 asymptomatic treatment-naive HIV-infected patients with CD4(+) T cells less than 350 cells/μl. Blood samples were evaluated at base line, and at 2, 4, 8 and 12 weeks' post antiretroviral therapy (ART). A biphasic increase of CD4(+) T cells, central memory CD4 cells (CD4 CM) and CD4 naïve cells were observed after ART, with a rapid increase before week 4. Change in CD4 CM at week 4 positively correlated with the change in CD4(+) T cells at weeks 12 post ART, and negatively correlated with the change in CD8(+)CD38(+) T cells at weeks 12 post ART. We conclude that CD4 CM cells are a major contributor to early immune reconstitution in treatment-naive HIV-infected patients with delayed ART, and might be an early indicator for immune reconstitution.

Characterization of quantitative and functional innate immune parameters in HIV-1-infected Colombian children receiving stable highly active antiretroviral therapy

BACKGROUND

The immunological benefits of highly active antiretroviral therapy (HAART) in HIV-1-infected children include reconstitution of CD4+ T-cell count and functional activity. The effect of HAART on innate immune cells has not been well established.

AIM

To characterize innate immune responses in HAART-treated HIV-1-infected children.

PATIENTS AND METHODS

23 HIV-1-infected children on stable HAART and 23 uninfected children were evaluated. The frequency of innate immune cells in peripheral blood was determined by flow cytometry and functional activity was evaluated using Toll-like receptor agonists.

RESULTS

Compared with uninfected children, HAART-treated HIV-1-infected children exhibited a significant decrease in the frequency of plasmacytoid dendritic cells and natural killer and T-cell receptor (TCR)-invariant CD1d-restricted T cells. This deficiency of innate immune cells was observed mainly in children with detectable viral load. We also compared the magnitude of the quantitative restoration of those cells comparing HIV-1-infected children with HIV-1-infected adults and found a partial effect of HAART on immune restoration that was independent of age. In both pediatric and adult subjects Toll-like receptor agonists induced expression of costimulatory molecules and production of proinflammatory cytokines by dendritic cells. Peripheral blood mononuclear cells of HIV-1-infected children produced significantly reduced amounts of interferon-alpha compared with uninfected children.

CONCLUSIONS

HAART administration to HIV-1-infected children does not lead to a complete increase of circulating innate immune cells, particularly in patients with incomplete suppression of HIV.

Immune reconstitution inflammatory syndrome and human immunodeficiency virus-associated myocarditis

Myocarditis is a well-recognized cardiac manifestation of human immunodeficiency virus (HIV) infection, and alterations in the immune system likely play an important role in the pathogenesis of heart muscle disease in HIV-infected patients. Highly active antiretroviral therapy (HAART) has greatly improved survival in HIV patients but not without uncovering new and unique manifestations of disease. Immune reconstitution inflammatory syndrome is a collection of inflammatory disorders in which a pathologic inflammatory response and clinical deterioration occur during recovery of the immune system after HAART. To our knowledge, a correlation between immune reconstitution inflammatory syndrome and HIV-associated myocarditis has not been described previously. We report a case of acute myocarditis presenting with refractory ventricular arrhythmias in a patient with AIDS who experienced rapid immune recovery with the initiation of HAART. The case underscores the importance of recognizing this potential complication of AIDS treatment and calls for renewed vigilance concerning cardiac manifestations of HIV, especially during the immune reconstitution phase.

Cryptococcal immune reconstitution inflammatory syndrome: report of four cases in three patients and review of the literature

Immune reconstitution inflammatory syndromes (IRIS) in patients with AIDS are characterized by atypical manifestations of opportunistic pathogens in patients experiencing improvement in CD4 cell counts following receipt of highly active anti-retroviral therapy (HAART). We report four cases of IRIS due to Cryptococcus neoformans in three patients and review the literature of cryptococcal IRIS in AIDS (an additional 21 episodes). The IRIS presentation was lymphadenitis in all three patients; one patient also had meningeal IRIS. Combining our patients with the literature review revealed the following IRIS presentations: lymphadenitis (n=14), central nervous system (CNS) IRIS (n=10): meningitis in six and mass lesions in four, and pulmonary cavities (n=1). The median CD4 count of cases at the time of initial cryptococcal diagnosis and prior to the start of HAART was 25 cells/microl and the median HIV viral load was 439,053 copies/ml. At time of presentation of the IRIS, the median CD4 count had increased by 197 cells/microl. The median time from initial cryptococcal diagnosis and the start of HAART to the IRIS was 11 months (range 7 weeks to 3 years) and 7 months (range <2 weeks to 22 months), respectively. Patients with CNS IRIS tended to have shorter intervals from initiation of HAART to presentation compared to patients with lymphadenitis: median 3.5 months compared to 7 months. In 24 of 25 cases, the clinical manifestations of the IRIS resolved (range: days to months). Only four patients were given anti-inflammatory medications: corticosteroids in two and non-steroidal anti-inflammatory drugs in two, thus precluding assessment of efficacy. Patients with cryptococcal disease who initiate HAART are at risk for cryptococcal IRIS.

Treatment outcomes after highly active antiretroviral therapy: a meta-analysis of randomised controlled trials

This systematic review summarises the evidence for treatment efficacy and tolerability of highly active antiretroviral therapies containing two nucleoside reverse transcriptase inhibitors (NRTI) with a protease inhibitor (PI), compared with two NRTIs alone for the treatment of HIV-1 infection in randomised controlled trials. Three electronic databases (Medline, Embase, and the Cochrane Library) were searched up to December 2003. 16 randomised controlled trials met the inclusion criteria and were included in the analysis from 328 articles screened. The pooled analysis indicated that treatment with two NRTIs with a PI is more effective in achieving viral suppression than two NRTIs alone (relative risk [RR] 3.44, 95% confidence interval [CI] 2.43-4.87). However, the RR for discontinuation of treatment due to adverse events of treatment with two NRTIs with a PI compared with two NRTIs alone was 1.81 (95% CI 1.17-2.79). The benefits of treatment with two NRTIs and a PI are substantial among those who can tolerate the regimen in comparison with treatment with two NRTIs alone.

Nadir CD4+ T-cell count and numbers of CD28+ CD4+ T-cells predict functional responses to immunizations in chronic HIV-1 infection

OBJECTIVE

To ascertain whether delaying the initiation of highly active antiretroviral therapy (HAART) compromises functional immune reconstitution in HIV-1 infection in persons who regain 'normal' CD4 T-cell counts after suppressive antiretroviral therapies.

DESIGN

Prospective open-label study carried out at two University-affiliated HIV-outpatient clinics in the USA.

SUBJECTS AND METHODS

Response to immunization was used as a model for in vivo functional immune competence in 29 HIV-1 infected patients with CD4 T-cell counts > 450 x 106 cells/l and HIV-RNA < 400 copies/ml for > 12 months after HAART and nine HIV-1 seronegative controls. After immunization with tetanus toxoid, diphtheria-toxoid, and keyhole limpet hemocyanin, immune response scores (IRS) were calculated using postimmunization antibody concentrations, lymphocyte proliferation, and delayed-type hypersensitivity responses to vaccine antigens.

RESULTS

Despite normal numbers of circulating CD4 T-cells, the CD4 T-cell nadir before HAART initiation predicted the immune response to immunization (rho = 0.5; P < 0.005) while current CD4 T-cell count did not. Likewise, CD4 T-lymphocyte expression of the co-stimulatory molecule CD28 was also an independent predictor of response to immunization (rho = 0.5; P < 0.005).

CONCLUSIONS

Even among persons who controlled HIV replication and normalized CD4 T-cell counts with HAART, pretreatment CD4 T-cell count and numbers of circulating CD4+CD28+ T-cells at immunization, but not current CD4 T-cell count, predict the ability to respond to vaccination. Delaying the initiation of HAART in chronic HIV-1 infection results in impaired functional immune restoration despite normalization of circulating CD4 T-cell numbers.

Can immune markers predict subsequent discordance between immunologic and virologic responses to antiretroviral therapy? Adult AIDS Clinical Trials Group

It is unclear why discordant immunologic and virologic responses occur during therapy for human immunodeficiency virus (HIV) infection. This study examined whether markers of immune activation and naive/memory lymphocyte subsets at study baseline could predict discordance between HIV type 1 (HIV-1) RNA and CD4+ lymphocyte responses at week 24 of antiretroviral therapy. Ten diverse, prospective antiretroviral studies with 1007 evaluable subjects were included. Subsets of subjects at increased risk for discordance were identified by recursive partitioning. The strongest predictor of more-favorable immunologic than virologic responses was a lower baseline CD4+ lymphocyte count. Weaker predictors in small subsets of subjects were fewer activated CD4+ lymphocytes and fewer CD8+ lymphocytes. Conversely, the strongest predictors of more-favorable virologic than immunologic responses were higher baseline CD4+ lymphocyte count and percentage. Additional predictors in some analyses were higher CD8+ lymphocyte count or percentage and lower HIV-1 RNA concentrations. Baseline markers of immune activation and naive/memory lymphocyte subsets had limited ability to predict subsequent discordance.

Correlates of antiviral immune restoration in acute and chronic HIV type 1 infection: sustained viral suppression and normalization of T cell subsets

Highly active antiretroviral therapy (HAART) has suppressed viral replication and facilitated normalization of T cell subsets, resulting in restoration of immunity against opportunistic pathogens. Induction of full immune restoration in chronically infected individuals, including HIV-specific helper T cell responses, is considered a priority, particularly if immunological control of HIV is to be achieved. Regimens containing dual protease inhibitors (PIs) have provided greater suppression of viremia than single-PI regimens. We therefore conducted a prospective analysis of factors associated with immune restoration after 3 years of therapy in two cohorts of acutely and chronically HIV-infected patients, comparing dual- versus single-PI regimens. Earlier and more durable returns of p24-specific proliferation were demonstrated in patients receiving dual-PI compared with single-PI regimens. Individuals with restored p24 responses had larger reductions in total HIV-specific cytotoxic T lymphocytes (CTLs) associated with stronger viral suppression, but Gag-specific CTLs remained higher, demonstrating that Gag-specific helper T cell responses were a critical component of functional immune restoration. On examination of clinical factors associated with immune restoration, we demonstrated that decreasing activation of CD8+ T cells (%CD8+ CD38+) and increasing proportions of CD4+ T cells were independently associated with restoration of p24 responses. Minimal immune activation, resulting from maximal suppression of viral replication, was required for long-term restoration and maintenance of Gag-specific T cell responses. This study uniquely demonstrates that dual-PI regimens are superior in achieving these levels of virological control and immune restoration in both chronic and acute infection, compared with single-PI or non-PI regimens.

Incidence of and risk factors for symptomatic visceral leishmaniasis among human immunodeficiency virus type 1-infected patients from Spain in the era of highly active antiretroviral therapy

The way in which the extensive use of highly active antiretroviral therapy (HAART) has influenced the incidence of visceral leishmaniasis (VL) among human immunodeficiency type 1 (HIV-1)-infected patients is not yet understood. The present study assessed whether the incidence of symptomatic VL in HIV-infected patients has decreased since the introduction of HAART. Likewise, the role of other potential risk factors for VL was also analyzed. Therefore, 479 HIV-1-infected patients receiving antiretroviral treatment, according to the available drugs at each moment, were prospectively followed from April 1989 to June 2000 in two university hospitals in southern Spain. A bone marrow aspiration was performed when patients showed symptoms suggestive of kala-azar. A diagnosis of VL was made when Leishmania amastigotes were seen in Giemsa-stained samples or promastigotes were cultured in specific media. The median follow-up time was 1,380 [8 to 4,536] days. Twenty-one patients were diagnosed with symptomatic VL. The density of incidence of VL has decreased 64.8% as of January 1997, when HAART began to be used extensively in our area. The use of HAART was the main independent factor associated with VL; this therapy was a protective factor (adjusted hazard ratio [HR], 0.05; 95% confidence interval [CI], 0.02 to 0.15). CDC clinical category C at entry in the cohort (HR, 4.08; 95% CI, 1.46 to 11.35) and CD4(+) cell counts below 300 cells/mm(3) during the follow-up (HR, 3.96; 95% CI, 1.56 to 10.01) were also independently associated with kala-azar. A VL diagnosis prior to follow-up and low compliance with antiretroviral therapy were not independently associated with symptomatic VL, although statistical significance was almost reached (P = 0.1 and P = 0.08, respectively). In summary, the use of HAART has led to a fall in the incidence of symptomatic VL in HIV-infected patients. The main risk factor associated with kala-azar emergence in patients infected with HIV is deep immunosuppression.

Interferon-alpha generation and immune reconstitution during antiretroviral therapy for human immunodeficiency virus infection

OBJECTIVES

To quantify the effect of HIV infection and HIV-suppressive therapy on interferon-alpha (IFN-alpha) production by human blood mononuclear cells; to compare, in parallel, effects on CD4+ T-cell numbers; and to ascertain the relationship of these interferon and CD4 parameters to resistance to opportunistic infections.

DESIGN

Serial studies of 294 unselected patients with HIV infection during therapy, with outcomes analysis.

METHODS

Determination of IFN generation by blood mononuclear cells via bioassay, and T-lymphocyte subset analysis via flow cytometry; serial studies of individual patients; linear regression and chi2 contingency table analysis.

RESULTS

HIV burden is inversely related to interferon-alpha generation, much as it is to CD4+ T-cell counts. Both of these recover during HIV-suppressive therapy. Reconstitution of IFN-alpha generation to levels commensurate with protection against opportunistic infection occurs prior to similar restoration of CD4 counts. In the outcomes analyses, such immune reconstitution was associated with protection from recurrent or new opportunistic infection. Conversely, viral suppression without such immunologic recovery was not protective against opportunistic infection.

CONCLUSIONS

Rapidly responding IFN-alpha generating cells appear to participate in resistance to opportunistic intracellular infection. Recovery of IFN-alpha generation may be an early marker of immune reconstitution in AIDS.

Antiretroviral agents restore Mycobacterium-specific T-cell immune responses and facilitate controlling a fatal tuberculosis-like disease in Macaques coinfected with simian immunodeficiency virus and Mycobacterium bovis BCG

The contribution of immune reconstitution following antiretroviral treatment to the prevention or treatment of human immunodeficiency virus-related primary or reactivation tuberculosis remains unknown. Macaque models of simian immunodeficiency virus-Mycobacterium bovis BCG (SIV/BCG) coinfection were employed to determine the extent to which anti-Mycobacterium tuberculosis immunity can be restored by antiretroviral therapy. Both SIV-infected macaques with active BCG reinfection and naive animals with simultaneous SIV/BCG coinfection were evaluated. The suppression of SIV replication by antiretroviral treatment resulted in control of the active BCG infection and blocked development of the fatal SIV-related tuberculosis-like disease. The resolution of this disease coincided with the restoration of BCG purified protein derivative (PPD)-specific T-cell immune responses. In contrast, macaques similarly coinfected with SIV/BCG but not receiving antiretroviral therapy had depressed PPD-specific primary and memory T-cell immune responses and died from tuberculosis-like disease. These results provide in vivo evidence that the restoration of anti-mycobacterial immunity by antiretroviral agents can improve the clinical outcome of an AIDS virus-related tuberculosis-like disease.

Influence of highly active antiretroviral therapy on the outcome of subclinical visceral leishmaniasis in human immunodeficiency virus-infected patients

Seventeen human immunodeficiency virus-infected patients who were harboring untreated subclinical visceral leishmaniasis (VL) were prospectively followed up. None of the 11 patients who received highly active antiretroviral therapy (HAART) presented with symptomatic VL during follow-up, whereas 2 out of 6 patients who received therapy other than HAART had an episode of overt kala-azar. These findings suggest that HAART does not induce the evolution of latent VL into symptomatic disease.