CD4+ T cell recovery with antiretroviral therapy: more than the sum of the parts

Enhanced IFN-γ, but not IL-2, response to Mycobacterium tuberculosis antigens in HIV/latent TB co-infected patients on long-term HAART

BACKGROUND

HIV-infected individuals with latent TB infection are at increased risk of developing active TB. HAART greatly reduces the incidence rate of TB in HIV-infected patients and reconstitutes Mycobacterium tuberculosis (M. tuberculosis)-specific immune response in the first 12 months of therapy. The durability of the anti-mycobacterial immune restoration after a year of HAART however remains less investigated.

METHOD

A cross-sectional study was conducted to evaluate M. tuberculosis-specific functional immune responses in HIV/latent TB co-infected patients who were on HAART for at least 1.5 up to 9 years as compared to HAART-naïve patients. Three-hundred sixteen HIV-infected patients without active TB were screened by tuberculin skin testing for M. tuberculosis infection and peripheral blood mononuclear cells (PBMCs) were isolated from 61 HIV/latent TB co-infected patients (30 HAART-naïve and 31 HAART-treated). IFN-γ and IL-2 ELISPOT as well as CFSE cell proliferation assays were performed after stimulation with M. tuberculosis antigens PPD and ESAT-6.

RESULT

The median frequency of PPD and ESAT-6 specific IFN-γ secreting cells was significantly higher in the HAART-treated patients as compared to HAART-naïve patients, p = 0.0021 and p = 0.0081 respectively. However, there was no significant difference in the median frequency of IL-2 secreting cells responding to PPD (p = 0.5981) and ESAT-6 (p = 0.3943) antigens between HAART-naïve and-treated groups. Both IFN-γ and IL-2 responses were independent of CD4+ T cell count regardless of the HAART status. Notably, the frequency of PPD and ESAT-6 specific IL-2 secreting cells was positively associated with CD4+ T cell proliferation while inversely correlated with duration of HAART, raising the possibility that M. tuberculosis-specific IL-2 response that promote the antigen-specific CD4+ T cell proliferation diminish with time on antiretroviral therapy in HIV/latent TB co-infected patients.

CONCLUSION

This study shows an increased M. tuberculosis-specific IFN-γ, but not IL-2, response in HIV/latent TB co-infected patients with long-term HAART, consistent with only partial immune restoration. Future studies should, therefore, be done to prospectively define the rate and extent to which functional immune responses to M. tuberculosis are restored after long-term HAART.

Longitudinal Changes in Cd4+, Cd8+ T Cell Phenotype and Activation Marker Expression Following Antiretroviral Therapy Initiation among Patients with Cryptococcal Meningitis

Despite improvement in the prognosis of HIV/AIDS (human immunodeficiency virus/acquired immune deficiency syndrome) patients on antiretroviral therapy (ART), cryptococcal meningitis (CM) still causes 10–15% mortality among HIV-infected patients. The immunological impact of ART on the CD4⁺ and CD8⁺ T cell repertoire during cryptococcal co-infection is unclear. We determined longitudinal phenotypic changes in T cell subsets among patients with CM after they initiated ART. We hypothesized that ART alters the clonotypic phenotype and structural composition of CD4⁺ and CD8⁺ T cells during CM co-infection. For this substudy, peripheral blood mononuclear cells (PBMC) were isolated at four time points from CM patients following ART initiation during the parent study (ClinicalTrials.gov number, NCT01075152). Phenotypic characterization of CD4⁺ and CD8⁺ T cells was done using T cell surface marker monoclonal antibodies by flow cytometry. There was variation in the expression of immunophenotypic markers defining central memory (CD27⁺CD45R0⁺), effector memory (CD45R0⁺CD27^–), immune activation (CD38⁺ and Human Leucocyte Antigen DR (HLA-DR⁺), and exhaustion (Programmed cell death protein one (PD-1) in the CD4⁺ T cell subset. In comparison to the CD4⁺ T cell population, the CD8⁺ central memory subset declined gradually with minimal increase in the effector memory subset. Both CD4⁺ and CD8⁺ T cell immune exhaustion and activation markers remained elevated over 12 weeks. The relative surge and decline in the expression of T cell surface markers outlines a variation in the differentiation of CD4⁺ T cells during ART treatment during CM co-infection.

Influence of comorbidities on CD4+/CD8+ proportion in HIV-positive patients in Blumenau, State of Santa Catarina: a retrospective study

INTRODUCTION

The objective was to identify comorbidities related to HIV-positive patients in Blumenau, State of Santa Catarina.

METHODS

A retrospective, descriptive observational design study which analyzed data from 424 patients assisted by the sexually transmitted disease/acquired immunodeficiency syndrome (STD/AIDS) Specialized Care Service (SCS).

RESULTS

Of 424 medical records analyzed, 388 patients presented CD4+/CD8+ ratios lower than 1. The most prevalent comorbidities were smoking, depression, alcoholism, and herpes zoster infection, in males and females.

CONCLUSIONS

The most relevant comorbidity in both genders was herpes zoster, an important marker of immunity in patients. The lowest mean was observed among patients with neurotoxoplasmosis.

Immune Reconstitution Inflammatory Syndrome in HIV-Infected Immigrants

Immune reconstitution inflammatory syndrome (IRIS) includes a group of potentially serious inflammatory processes that may be present in HIV-infected patients after initiating highly active antiretroviral therapy (HAART). Paradoxical IRIS is a worsening of symptoms, after an overwhelming response to a previously diagnosed opportunistic infection (OI); unmasking IRIS reveals a previously occult OI. The main objective of the study was to describe the epidemiological, clinical, and outcome data of HIV-infected immigrants, stratified according to high- or low-income countries of origin, who developed IRIS and to compare them with native-born Spanish patients. This retrospective study reviewed all patients with HIV infection admitted to the Unit of Infectious Diseases and Tropical Medicine between 1998 and 2014. IRIS was identified in 25/138 (18%) immigrant patients and 24/473 (5%) native-born Spanish patients infected with HIV. Most cases, 19/25 (76%), were of unmasking IRIS. The time elapsed between initiation of HAART and development of IRIS was significantly longer in patients with unmasking versus paradoxical IRIS. OIs, in particular due to mycobacteria, were the most frequently involved processes. Twenty percent of patients died. The comparison of immigrant and native-born patients found significant differences for both IRIS type (higher incidence of paradoxical forms among immigrants) and for the absence of malignancies in native-born patients. No significant differences were found when the data of immigrants from low- and high-income countries were compared.

CD4+ cells recovery in HIV positive patients with severe immunosuppression at HAART initiation at Centre Medico-Social Cor-Unum, Kigali

INTRODUCTION

Up to 30% of HIV infected patients who are receiving HAART do not exhibit a marked increase in the CD4+ T cell count. There is still a concern that immune recovery may not be complete once CD4+ T cells have decreased below 200 cells/μl. The objective is to assess CD4+ cell recovery in HIV+ patients with CD4 count below 200 cells/μl) at HAART initiation.

METHODS

This was a retrospective cohort study among 110 HIV+ patients with initial CD4 count < 200 cells/μl. Baseline Age, sex, CD4 count and viral load were extracted from the patient's database. After12 months of HAART; CD4 count was done using flow cytometry and viremia by COBAS AmpliPrep/COBAS TaqMan HIV-1 test v 2.0 technology.

RESULTS

The mean age of the respondents was 35 years; males being 57% and females were 43%. The mean CD4 count before HAART was 110.18 cells/μl whereas at 12 months of HAART; this was 305.01 cells/μl. Though some patients did not achieve a CD4 count of more than 200 cells/μl or a drop in viral load; there was a significant recovery of CD4+ cells (P value=0.000) and viremia following HAART (P value=0.001). Participants aged 18-30 years were likely to have less than 200 cells/μl CD4 count (46.4%) [OR=4.33; 95%CI: 1.29-14.59; P=0.018] than participants aged above 40 years (16.7%).

CONCLUSION

HAART was associated with viremia suppression but many patients failed to achieve a CD4 count >200 cells/μl. HAART before severe immunosuppression is a key factor for immune restoration among HIV+ patients.

Changes in coronary heart disease risk profiles of HIV patients in Zimbabwe over 9 months: a follow-up study

Dyslipidemia, hypertension, inflammation, and coronary heart disease (CHD) are adverse events in human immunodeficiency virus (HIV)-infected patients even if they are receiving antiretroviral therapy (ART). Yet, data on CHD risk induced by HIV or ART in sub-Saharan Africa are limited. The aim of this longitudinal study was to describe changes in CHD risk profiles measured by lipids, inflammatory markers, and Framingham scores among HIV-positive patients previously reported from Harare, Zimbabwe. Patients were grouped into ART-experienced patients (n=147) and ART-naïve patients (n=23) and followed up for 9 months. Generalized least squares random-effects modeling was applied to explain changes in total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein, TC/HDL ratio, myeloperoxidase, highly sensitive C-reactive protein, and Framingham scores over the 9-month period. Independent variables included age, sex, monthly earning, body mass index, systolic blood pressure (SBP), diastolic blood pressure, duration of HIV diagnosis, duration of ART, viral load, and CD4 count. In ART-experienced patients, there was a substantial decrease in TC over time, ART-negative patients showed a significant increase in TC and HDL over time, and the increase in TC was associated with high viral load and low duration of HIV diagnosis, while increase in HDL was associated with young age, low body mass index, and low SBP. Framingham risk scores increased with time in ART-positive patients, and the change was positively correlated with age, sex, high SBP, and low HDL. There was no association between calculated CHD risk (TC/HDL ratio or Framingham score) and changes in levels of inflammatory markers (myeloperoxidase and highly sensitive C-reactive protein) in any of the patient groups. In conclusion, ART-experienced HIV-positive patients show changes in lipid values over time that makes it necessary to include lipid monitoring in order to reduce any risk of long-term CHD.

Non-initiation of hepatitis C virus antiviral therapy in patients with human immunodeficiency virus/hepatitis C virus co-infection

AIM

To assess whether reasons for hepatitis C virus (HCV) therapy non-initiation differentially affect racial and ethnic minorities with human immunodeficiency virus (HIV)/HCV co-infection.

METHODS

Analysis included co-infected HCV treatment-naïve patients in the University of North Carolina CFAR HIV Clinical Cohort (January 1, 2004 and December 31, 2011). Medical records were abstracted to document non-modifiable medical (e.g., hepatic decompensation, advanced immunosuppression), potentially modifiable medical (e.g., substance abuse, severe depression, psychiatric illness), and non-medical (e.g., personal, social, and economic factors) reasons for non-initiation. Statistical differences in the prevalence of reasons for non-treatment between racial/ethnic groups were assessed using the two-tailed Fisher's exact test. Three separate regression models were fit for each reason category. Odds ratios and their 95%CIs (Wald's) were computed.

RESULTS

One hundred and seventy-one patients with HIV/HCV co-infection within the cohort met study inclusion. The study sample was racially and ethnically diverse; most patients were African-American (74%), followed by Caucasian (19%), and Hispanic/other (7%). The median age was 46 years (interquartile range = 39-50) and most patients were male (74%). Among the 171 patients, reasons for non-treatment were common among all patients, regardless of race/ethnicity (50% with ≥ 1 non-modifiable medical reason, 66% with ≥ 1 potentially modifiable medical reason, and 66% with ≥ 1 non-medical reason). There were no significant differences by race/ethnicity. Compared to Caucasians, African-Americans did not have increased odds of non-modifiable [adjusted odds ratio (aOR) = 1.47, 95%CI: 0.57-3.80], potentially modifiable (aOR = 0.72, 95%CI: 0.25-2.09) or non-medical (aOR = 0.90, 95%CI: 0.32-2.52) reasons for non-initiation.

CONCLUSION

Race/ethnicity alone is not predictive of reasons for HCV therapy non-initiation. Targeted interventions are needed to improve access to therapy for all co-infected patients, including minorities.

Delayed reconstitution of B cell immunity to pneumococcus in HIV-infected Malawian children on antiretroviral therapy

OBJECTIVE

Despite CD4(+) count restoration and viral load suppression with antiretroviral therapy (ART), HIV-infected children remain at increased risk of life-threatening infections including invasive pneumococcal disease (IPD). We therefore investigated whether persistent susceptibility to IPD following ART is associated with incomplete recovery of B-cell function.

METHODS

41 HIV-infected Malawian children commencing ART were followed-up for a 1 year period during which time blood samples were collected at 0, 3, 6 and 12 months for comprehensive immunophenotyping and pneumomococcal-specific Memory B-cell Enzyme-Linked Immunospot assays. In addition, nasopharyngeal swab samples were cultured to determine pneumococcal carriage rates.

RESULTS

Normalization of major lymphocyte subsets such as CD4(+) percentages was evident following 3 months of ART. The proportions of mature naïve B cells (CD19(+) CD10(-) CD27(-) CD21(hi)) and resting memory B cells (CD19(+) CD27(+) CD21(hi)) increased and apoptosis-prone mature activated B cells (CD19(+) CD21(lo) CD10(-)) decreased markedly by 12 months. However, in the context of high nasopharyngeal pneumococcal carriage rates (83%), restoration of pneumococcal protein antigen-specific B-cell memory was more delayed.

CONCLUSIONS

These data show that, in chronically HIV-infected children receiving ART, improvement in B-cell memory profiles and function is slower than CD4(+) T-cells. This supports early initiation of ART and informs research into optimal timing of immunization with pneumococcal vaccines.

CD4(+) T Cells Modified by the Endoribonuclease MazF Are Safe and Can Persist in SHIV-infected Rhesus Macaques

MazF, an endoribonuclease encoded by Escherichia coli, specifically cleaves the ACA (adenine–cytosine–adenine) sequence of single-stranded RNAs. Conditional expression of MazF under the control of the HIV-1 LTR promoter rendered CD4⁺ T cells resistant to HIV-1 replication without affecting cell growth. To investigate the safety, persistence and efficacy of MazF-modified CD4⁺ T cells in a nonhuman primate model in vivo, rhesus macaques were infected with a pathogenic simian/human immunodeficiency virus (SHIV) and transplanted with autologous MazF-modified CD4⁺ T cells. MazF-modified CD4⁺ T cells were clearly detected throughout the experimental period of more than 6 months. The CD4⁺ T cell count values increased in all four rhesus macaques. Moreover, the transplantation of the MazF-modified CD4⁺ T cells was not immunogenic, and did not elicit cellular or humoral immune responses. These data suggest that the autologous transplantation of MazF-modified CD4⁺ T cells in the presence of SHIV is effective, safe and not immunogenic, indicating that this is an attractive strategy for HIV-1 gene therapy.

Novel cell and gene therapies for HIV

Highly active antiretroviral therapy dramatically improves survival in HIV-infected patients. However, persistence of HIV in reservoirs has necessitated lifelong treatment that can be complicated by cumulative toxicities, incomplete immune restoration, and the emergence of drug-resistant escape mutants. Cell and gene therapies offer the promise of preventing progressive HIV infection by interfering with HIV replication in the absence of chronic antiviral therapy. Individuals homozygous for a deletion in the CCR5 gene (CCR5Δ32) are largely resistant to infection from R5-topic HIV-1 strains, which are most commonly transmitted. A recent report that an HIV-infected patient with relapsed acute myelogenous leukemia was effectively cured from HIV infection after transplantation of hematopoietic stem/progenitor cells (HSC) from a CCR5Δ32 homozygous donor has generated renewed interest in developing treatment strategies that target viral reservoirs and generate HIV resistance in a patient's own cells. Although the development of cell-based and gene transfer therapies has been slow, progress in a number of areas is evident. Advances in the fields of gene-targeting strategies, T-cell-based approaches, and HSCs have been encouraging, and a series of ongoing and planned trials to establish proof of concept for strategies that could lead to successful cell and gene therapies for HIV are under way. The eventual goal of these studies is to eliminate latent viral reservoirs and the need for lifelong antiretroviral therapy.

Reduced thymic output is a major mechanism of immune reconstitution failure in HIV-infected patients after long-term antiretroviral therapy

BACKGROUND

Approximately 20% of human immunodeficiency virus type 1 (HIV-1)--infected adults do not normalize their CD4(+) T lymphocytes after long-term effective highly active antiretroviral therapy (HAART). The mechanistic basis for this failure is unclear.

METHODS

Seventy-four patients were followed up regularly for 3-7 years. Patients with undetectable plasma viral load (<50 copies/mL) for over 12 months were further classified into 2 groups: (1) immunological nonresponders, whose CD4(+) T-cell count was < 200/μL or <20% compared with baseline; and (2) immunological responders, whose CD4(+) T-cell count was > 300/μL or >30% compared with baseline.

RESULTS

Compared with 17 immunological responders, 13 immunological nonresponders had a lower magnitude of naive CD4(+) T-cell increase, a lower percentage of recent thymic immigrants (CD31(+)%), and a higher percentage of activated CD8(+) T cells. Furthermore, unlike CD4(+) T cells, which increased along with the decrease of viral load, the percentage of recent thymic immigrants (CD31(+)%) had little change in the majority of patients. These data were fit into a mathematical model, , from which we deduced that the initial rate of CD4(+) T-cell restoration is associated significantly with the percentage of recent thymic immigrants (CD31(+)%).

CONCLUSIONS

Our data indicate that the failure to restore CD4(+) T-cell count following HAART was associated primarily with a defect in recent thymic immigrants, which suggests the existence of thymus exhaustion.

Incidence and predictors of immune reconstitution inflammatory syndrome in a rural area of Mozambique

Background

There is limited data on the epidemiology of Immune Reconstitution Inflammatory Syndrome (IRIS) in rural sub-Saharan Africa. A prospective observational cohort study was conducted to assess the incidence, clinical characteristics, outcome and predictors of IRIS in rural Mozambique.

Methods

One hundred and thirty-six consecutive antiretroviral treatment (ART)-naïve HIV-1-infected patients initiating ART at the Manhiça district hospital were prospectively followed for development of IRIS over 16 months. Survival analysis by Cox regression was performed to identify pre-ART predictors of IRIS development.

Results

Thirty-six patients developed IRIS [26.5%, incidence rate 3.1 cases/100 persons-month of ART (95% CI 2.2–4.3)]. Median time to IRIS onset was 62 days from ART initiation (IQR 35.5–93.5). Twenty-five cases (69.4%) were “unmasking”, 10 (27.8%) were “paradoxical”, and 1 (2.8%) developed a paradoxical worsening followed by the unmasking of another condition. Systemic OI (OI-IRIS) accounted for 47% (17/36) of IRIS cases, predominantly of KS (8 cases) and TB (6 cases) IRIS. Mucocutaneous IRIS manifestations (MC-IRIS) accounted for 53% (19/36) of IRIS events, mostly tinea (9 cases) and herpes simplex infection (3 cases). Multivariate analysis identified two independent predictors of IRIS development: pre-ART CD4 count <50 cells/µl (HR 2.3, 95% CI 1.19–4.44, p = 0.01) and body mass index (BMI) <18.5 (HR 2.15, 95% CI 1.07–4.3, p = 0.03). The pre-cART proportion of activated T-cells, as well as the immunologic and virologic response to ART were not associated with IRIS development. All patients continued on ART, 7 (19.4%) required hospitalization and there were 3 deaths (8.3%) attributable to IRIS.

Conclusions

IRIS is common in patients initiating ART in rural Mozambique. Pre-ART CD4 counts and BMI can easily be assessed at ART initiation in rural sub-Saharan Africa to identify patients at high risk of IRIS, for whom close supervision is warranted.

Factors associated with collagen deposition in lymphoid tissue in long-term treated HIV-infected patients

OBJECTIVE

The factors associated with fibrosis in lymphoid tissue in long-term treated HIV-infected patients and their correlation with immune reconstitution were assessed.

METHODS

Tonsillar biopsies were performed in seven antiretroviral-naive patients and 29 successfully treated patients (median time on treatment, 61 months). Twenty patients received protease inhibitors-sparing regimens and nine protease inhibitor-containing regimens. Five tonsillar resections of HIV-negative individuals were used as controls. Lymphoid tissue architecture, collagen deposition (fibrosis) and the mean interfollicular CD4(+) cell count per mum were assessed.

RESULTS

Naive and long-term treated HIV-infected patients had a higher proportion of fibrosis than did HIV-uninfected persons (P < 0.001). Patients with greater collagen deposition showed lower levels of CD4 cells in lymphoid tissue (P = 0.03) and smaller increase in peripheral CD4(+) T cells (r = -0.40, P = 0.05). The factors independently associated with fibrosis in lymphoid tissue were age (P < 0.0001), treated patients with detectable lymphoid tissue viral load when compared with patients with undetectable lymphoid tissue viral load (median 5 vs. 12%, respectively, P = 0.017) and patients receiving a protease inhibitor-sparing vs. a protease inhibitor-containing regimen (median 8 vs. 2.5%, respectively, P = 0.04).

CONCLUSION

Fibrosis in lymphoid tissue was associated with a poor reconstitution of CD4(+) T cells and long-term antiretroviral therapy did not reverse this abnormality. HIV infection, older age, a detectable level of lymphoid tissue viral load in treated patients and protease inhibitor-sparing regimens seem to favour fibrosis in lymphoid tissue.

Effectiveness of a 'hunter' virus in controlling human immunodeficiency virus type 1 infection

Engineered therapeutic viruses provide an alternative method for treating infectious diseases, and mathematical models can clarify the system's dynamics underlying this type of therapy. In particular, this study developed models to evaluate the potential to contain human immunodeficiency virus type 1 (HIV-1) infection using a genetically engineered 'hunter' virus that kills HIV-1-infected cells. First, we constructed a novel model for understanding the progression of HIV infection that predicted the loss of the immune system's CD4(+) T cells across time. Subsequently, it determined the effects of introducing hunter viruses in restoring cell population. The model implemented direct and indirect mechanisms by which HIV-1 may cause cell depletion and an immune response. Results suggest that the slow progression of HIV infection may result from a slowly decaying CTL immune response, leading to a limited but constant removal of uninfected CD4 resting cells through apoptosis - and from resting cell proliferation that reduces the rate of cell depletion over time. Importantly, results show that the hunter virus does restrain HIV infection and has the potential to allow major cell recovery to 'functional' levels. Further, the hunter virus persisted at a reduced HIV load and was effective either early or late in the infection. This study indicates that hunter viruses may halt the progression of the HIV infection by restoring and sustaining high CD4(+) T-cell levels.

Recent key advances in human immunodeficiency virus medicine and implications for China

In this article we summarize several recent major developments in human immunodeficiency virus treatment, prevention, outcome, and social policy change. Updated international guidelines endorse more aggressive treatment strategies and safer antiretroviral drugs. New antiretroviral options are being tested. Important lessons were learned in the areas of human immunodeficiency virus vaccines and microbicide gels from clinical studies, and additional trials in prevention, especially pre-exposure prophylaxis, are nearing completion. Insight into the role of the virus in the pathogenesis of diseases traditionally thought to be unrelated to acquired immunodeficiency syndrome has become a driving force for earlier and universal therapy. Lastly, we review important achievements of and future challenges facing China as she steps into her eighth year of the National Free Antiretroviral Treatment Program.

Strategies to promote adherence to antiretroviral therapy applied by Dutch HIV nurse consultants: a descriptive qualitative study

This study describes strategies used by Dutch HIV nurse consultants to promote adherence to antiretroviral therapy (ART) and the assumptions on which these strategies were based. The study used a descriptive qualitative design with individual and focus group interviews. Individual semi-structured interviews (n = 23) focusing on adherence-supporting procedures and case-based focus groups (3 groups with 5-7 participants each) focusing on adherence strategies were held with HIV nurse consultants (n = 19). The strategies described were mainly based on experience. Theoretical principles were rarely discussed and participants seldom referred to the literature. Adherence-promoting strategies were identified for two phases: (a) before beginning ART and (b) during follow-up care while on ART. Strategies that were not used in one specific phase were categorized under "all phases." Data yielded useful ideas for the care of HIV-infected patients, and findings can be applied to the development and use of adherence-promoting strategies.

Inhibition of envelope-mediated CD4+-T-cell depletion by human immunodeficiency virus attachment inhibitors

Human immunodeficiency virus type 1 (HIV-1) envelope (Env) binding induces proapoptotic signals in CD4(+) T cells without a requirement of infection. Defective virus particles, which represent the majority of HIV-1, usually contain a functional Env and therefore represent a potentially significant cause of such CD4(+)-T-cell loss. We reasoned that an HIV-1 inhibitor that prohibits Env-host cell interactions could block the destructive effects of defective particles. HIV-1 attachment inhibitors (AIs), which potently inhibit Env-CD4 binding and subsequent downstream effects of Env, display low-nanomolar antiapoptotic potency and prevent CD4(+)-T-cell depletion from mixed lymphocyte cultures, also with low-nanomolar potency. Specific Env amino acid changes that confer resistance to AI antientry activity eliminate AI antiapoptotic effects. We observed that CD4(+)-T-cell destruction is specific for CXCR4-utilizing HIV-1 strains and that the fusion blocker enfuvirtide inhibits Env-mediated CD4(+)-T-cell killing but is substantially less potent than AIs. These observations, in conjunction with observed antiapoptotic activities of soluble CD4 and the CXCR4 blocker AMD3100, suggest that this AI activity functions through a mechanism common to AI antientry activity, e.g., prevention of Env conformation changes necessary for specific interactions with cellular factors that facilitate viral entry. Our study suggests that AIs, in addition to having potent antientry activity, could contribute to immune system homeostasis in individuals infected with HIV-1 that can engage CXCR4, thereby mitigating the increased risk of adverse clinical events observed in such individuals on current antiretroviral regimens.

[Human immunodeficiency virus and AIDS-associated immune reconstitution syndrome. State of the art]

Since the arrival of highly active antiretroviral therapy (HAART), immune reconstitution syndrome (IRS) has become an increasingly more frequent complication in patients with human immunodeficiency virus (HIV) infection. This article presents a review of the available evidence on this subject, indexed in MEDLINE-PUBMED, BVS-BIREME, and BioMed Central. The review covers the definition, epidemiology, classification, and diagnostic criteria related to IRS. In addition, the clinical particularities of the most frequent etiologies are described, and a proposal for a therapeutic approach is formulated. The prognosis and future implications of this syndrome in the epidemiology of some infectious illnesses in the HIV-positive population are included. Several unresolved aspects are mentioned, such as those related to the pathophysiology of the condition, use of biomarkers for the diagnosis, and the need for evidence-based therapeutic algorithms to enable standardization of treatment for these patients.