Promising PEGylated cationic dendrimers for delivery of miRNAs as a possible therapy against HIV-1 infection

BACKGROUND

The appearance of resistance against new treatments and the fact that HIV-1 can infect various cell types and develop reservoirs and sanctuaries makes it necessary to develop new therapeutic approaches to overcome those failures.

RESULTS

Studies of cytotoxicity, genotoxicity, complexes formation, stability, resistance, release and particle size distribution confirmed that G2-SN15-PEG, G3-SN31-PEG, G2-SN15-PEG-FITC and G3-SN31-PEG-FITC dendrimers can form complexes with miRNAs being biocompatible, stable and conferring protection to these nucleic acids. Confocal microscopy and flow cytometry showed effective delivery of these four dendrimers into the target cells, confirming their applicability as delivery systems. Dendriplexes formed with the dendrimers and miRNAs significantly inhibited HIV-1 infection in PBMCs.

CONCLUSIONS

These dendrimers are efficient delivery systems for miRNAs and they specifically and significantly improved the anti-R5-HIV-1 activity of these RNA molecules.

Nanotechnology against human cytomegalovirus in vitro: polyanionic carbosilane dendrimers as antiviral agents

BACKGROUND

Human cytomegalovirus (HCMV) is a worldwide infection, causing different troublesome in immunosupressed patients and very related to Human Immunodeficiency Virus 1 (HIV-1) infection, mainly in developing countries, with a co-infection rate of 80% in Africa. The high cost of present treatments and the lack of routinely tests in these countries urge the necessity to develop new molecules or strategies against HCMV. The new treatments should be low-cost and capable of avoiding the emerging problem of resistant virus. Nanoparticles play an important role in several viral infections. Our main focus is to study the potential activity of polyanionic carbosilane dendrimers (PDC), which are hyperbranched molecules with several sulfonate or sulfate groups in their periphery, against different viruses.

RESULTS

We studied the activity of G1-S4, G2-S16 and G2-S24P PDCs in MRC-5 cell line against HCMV infection by several plaque reduction assays. Our results show that dendrimers present good biocompatibility at the concentrations tested (1-50 µM) for 6 days in cell culture. Interestingly, both G2-S16 and G2-S24P showed a remarked inhibition at 10 µM against HCMV infection. Results on attachment and virucidal assays indicated that the inhibition was not directed to the virus or the virus-cell attachment. However, results of time of addition, showed a longer lasting activity of these dendrimers in comparison to ganciclovir, and the combination of G2-S16 or G2-S24P with ganciclovir increases the HCMV inhibition around 90 %.

CONCLUSIONS

Nanotechnology, in particular polyanionic carbosilane dendrimers, have proved their potential application against HCMV, being capable of inhibiting the infection by themselves or enhancing the activity of ganciclovir, the actual treatment. These compounds represent a low-cost approach to fight HCMV infections.

Nanoparticle-Delivered HIV Peptides to Dendritic Cells a Promising Approach to Generate a Therapeutic Vaccine

Finding a functional cure for HIV-1 infection will markedly decrease the social and economic burden of this disease. In this work, we have taken advantage of the antigen presenting cell role of human dendritic cells (DCs) to try to induce an immune response to HIV-derived peptide delivered to DCs using two different polycationic nanoparticles: a G4 PAMAM dendrimer modified to a 70/30 ratio of hydroxyl groups/amines and a cyclodextrin derivative. We have studied peptide delivery using a fluorescence peptide and have studied the immune response generation by cytokine determination and flow cytometry. We have found a robust delivery of the antigenic peptide to DCs and activated dendritic cell-mediated peripheral blood mononuclear cells (PBMCs) proliferation using the mixed lymphocyte reaction. However, no expression of markers indicating activation of either B or T lymphocytes was observed. Moreover, the release of the pro-inflammatory cytokine TNF-α or IL-2 was only observed when DCs treated with either the dendrimer or the dendriplex containing the peptide. Antigenic peptide delivery to DCs is a promising approach to generate a vaccine against HIV-1 infection. However, more studies, including the simultaneous delivery of several antigenic peptides from different viral proteins, can markedly improve the immune response.

Early and Highly Suppressive Antiretroviral Therapy Are Main Factors Associated With Low Viral Reservoir in European Perinatally HIV-Infected Children

BACKGROUND

Future strategies aiming to achieve HIV-1 remission are likely to target individuals with small reservoir size.

SETTING

We retrospectively investigated factors associated with HIV-1 DNA levels in European, perinatally HIV-infected children starting antiretroviral therapy (ART) <6 months of age.

METHODS

Total HIV-1 DNA was measured from 51 long-term suppressed children aged 6.3 years (median) after initial viral suppression. Factors associated with log10 total HIV-1 DNA were analyzed using linear regression.

RESULTS

At ART initiation, children were aged median [IQR] 2.3 [1.2-4.1] months, CD4% 37 [24-45] %, CD8% 28 [18-36] %, log10 plasma viral load (VL) 5.4 [4.4-5.9] copies per milliliter. Time to viral suppression was 7.98 [4.6-19.3] months. After suppression, 13 (25%) children had suboptimal response [≥2 consecutive VL 50-400 followed by VL <50] and/or experienced periods of virological failure [≥2 consecutive VL ≥400 followed by VL <50]. Median total HIV-1 DNA was 43 [6195] copies/10 PBMC. Younger age at therapy initiation was associated with lower total HIV-1 DNA (adjusted coefficient [AC] 0.12 per month older, P = 0.0091), with a month increase in age at ART start being associated with a 13% increase in HIV DNA. Similarly, a higher proportion of time spent virally suppressed (AC 0.10 per 10% higher, P = 0.0022) and the absence of viral failure/suboptimal response (AC 0.34 for those with fail/suboptimal response, P = 0.0483) were associated with lower total HIV-1 DNA.

CONCLUSIONS

Early ART initiation and a higher proportion of time suppressed are linked with lower total HIV-1 DNA. Early ART start and improving adherence in perinatally HIV-1-infected children minimize the size of viral reservoir.

Carbosilane dendrons with fatty acids at the core as a new potential microbicide against HSV-2/HIV-1 co-infection

Herpes simplex virus type 2 (HSV-2) and human immunodeficiency virus type 1 (HIV-1) represent the two most frequent sexually transmitted infections (STI) worldwide. Epidemiological studies suggest that HSV-2 increases the risk of HIV-1 acquisition approximately 3-fold mainly due to the clinical and immunological manifestations. In the absence of vaccines against both STI, the development of new preventive strategies has become essential for further studies. We performed the screening of six novel polyanionic carbosilane dendrons to elucidate their potential activity against HSV-2/HIV-1 co-infection and their mechanism of action. These new nanoparticles are carbosilane branched dendrons from first to third generation, with palmitic or hexanoic fatty acids as the core and capped with sulfonate groups, named G1_d-STE2Hx, G2_d-STE4Hx, G3_d-STE8Hx, G1_d-STE2Pm, G2_d-STE4Pm and G3_d-STE8Pm. G3_d-STE8Hx and G3_d-STE8Pm carbosilane branched dendrons showed high viability. These dendrons also showed a great broad-spectrum antiviral activity, as well as a suitable efficacy against HIV-1 even if the mucosal disruption occurs as a consequence of HSV-2 infection. Our results exert high inhibition against HSV-2 and HIV-1 by blocking the entry of both viruses with the median effective concentration EC₅₀ values in the nanomolar range. Additionally, G3_d-STE8Hx and G3_d-STE8Pm retained their anti-HSV-2/HIV-1 activity at different pH values. G3_d-STE8Hx and G3_d-STE8Pm dendrons may be potential candidates as dual-acting microbicides against HSV-2/HIV-1 co-infection.

Relationship between CCR5(WT/Δ32) heterozygosity and HIV-1 reservoir size in adolescents and young adults with perinatally acquired HIV-1 infection

BACKGROUND

Several host factors contribute to human immunodeficiency virus (HIV) disease progression in the absence of combination antiretroviral therapy (cART). Among them, the CC-chemokine receptor 5 (CCR5) is known to be the main co-receptor used by HIV-1 to enter target cells during the early stages of an HIV-1 infection.

OBJECTIVE

We evaluated the association of CCR5^(WT/Δ32) heterozygosity with HIV-1 reservoir size, lymphocyte differentiation, activation and immunosenescence in adolescents and young adults with perinatally acquired HIV infection receiving cART.

METHODS

CCR5 genotype was analysed in 242 patients with vertically transmitted HIV-1 infection from Paediatric Spanish AIDS Research Network Cohort (coRISpe). Proviral HIV-1 DNA was quantified by digital-droplet PCR, and T-cell phenotype was evaluated by flow cytometry in a subset of 24 patients (ten with CCR5^(Δ32/WT) genotype and 14 with CCR5^(WT/WT) genotype).

RESULTS

Twenty-three patients were heterozygous for the Δ32 genotype but none was homozygous for the mutated CCR5 allele. We observed no difference in the HIV-1 reservoir size (455 and 578 copies of HIV-1 DNA per million CD4⁺ T cells in individuals with CCR5^(WT/WT) and CCR5^(Δ32/WT) genotypes, respectively; p 0.75) or in the immune activation markers between both genotype groups. However, we found that total HIV-1 DNA in CD4⁺ T cells correlated with the percentage of memory CD4⁺ T cells: a direct correlation in CCR5^(WT/Δ32) patients but an inverse correlation in those with the CCR5^(WT/WT) genotype.

CONCLUSIONS

This finding suggests a differential distribution of the viral reservoir compartment in CCR5^(WT/Δ32) patients with perinatal HIV infection, which is a characteristic that may affect the design of strategies for reservoir elimination.

Maraviroc contributes to the restoration of the homeostasis of regulatory T-cell subsets in antiretroviral-naive HIV-infected subjects

Regulatory T (Treg) cells comprise different functional subsets with different CCR5 expression. Treg homeostasis is disrupted by HIV but the effect of treatment has barely been explored. In a longitudinal design, we compared the effect of a maraviroc-containing (n = 9) or sparing (n = 12) therapy in antiretroviral-naive HIV-positive participants on peripheral FoxP3(low) CD45RA(+) (nTreg), FoxP3(high) CD45RA(-) (eTreg) and FoxP3(low) CD45RA(-) (non-Treg) cells. Maraviroc significantly reduced all subsets in the short-term and, except for nTreg cells, also normalized them in the long-term. The correlation between eTreg cells and CD4 counts, lost before treatment, was only restored by maraviroc. The differential effect of maraviroc on Treg subsets contributes to understanding its immunomodulatory effects.

Phenotype and Polyfunctional Deregulation Involving Interleukin 6 (IL-6)- and IL-10-Producing Monocytes in HIV-Infected Patients Receiving Combination Antiretroviral Therapy Differ From Those in Healthy Older Individuals

BACKGROUND

Despite the relevance of monocytes as promoters of the inflammatory response, whether human immunodeficiency virus (HIV) infection induces premature age-related changes to the phenotype and function of monocytes or whether these alterations are different and/or specifically driven by HIV remains to be mechanistically determined.

METHODS

We assayed the activation phenotype and the responsiveness in vitro to Toll-like receptor (TLR) agonists in classical, intermediate, and nonclassical subsets of monocytes by assessing intracellular interleukin 1α (IL-1α), IL-1β, interleukin 6 (IL-6), interleukin 8, tumor necrosis factor α, and interleukin 10 (IL-10) production in 20 HIV-infected patients receiving combination antiretroviral therapy (cART) and 2 groups of uninfected controls (20 age-matched young individuals and 20 older individuals aged >65 years).

RESULTS

HIV-infected patients showed a more activated phenotype of monocytes than older controls. Regarding functionality, under unstimulated conditions HIV-infected patients showed a higher percentage of classical monocytes producing IL-6 and IL-10 than control subjects. The percentage of cells with production of multiple cytokines (polyfunctionality), including IL-10, in response to TLR agonists was greater among HIV-infected patients than among control subjects.

CONCLUSIONS

Inflammatory alterations associated with monocytes during HIV infection are different from those in aging individuals. This monocyte dysfunction, mainly characterized by high levels of IL-6- and IL-10-producing monocytes, may have clinical implications in HIV-infected patients that are different from those in aging individuals.

Disease disclosure, treatment adherence, and behavioural profile in a cohort of vertically acquired HIV-infected adolescents. NeuroCoRISpeS study

Advances in care and antiretroviral treatment, improved life expectancy and quality of life in children with perinatally-acquired human immunodeficiency virus (HIV) infection. There is increasing interest in the chronic effects of growing up with HIV. The aim of this study was to assess the psychosocial, emotional and behavioural functioning in a cohort of perinatally-acquired HIV-infected adolescents. Data were obtained through semi-structured interviews and the Strengths and Difficulties Questionnaire (SDQ) for emotional and behavioural disorders screening.

RESULTS

A total of 95 patients (58% women) were assessed with a median age of 15 years (11-19.1) and a median age at diagnosis of 1.7 years (0-12.2). The median CD4 count, at the inclusion, was 626 cells/mm(3) (132-998), with 34% (10-52%). Viral load was <50 copies/ml in 72% of patients. Eighty-one per cent knew their diagnosis and optimal adherence was achieved in 53%. Passive coping was reported in 58.4% of the adolescents. Only 7.7% of teenagers had a complete and adequate knowledge of their disease and only 18.2% had shared it with their friends. Six unwanted pregnancies occurred (11% of women). Most of them (90%) attended school but 60% had been held back one or more school years. Overall, SDQ scored a risk of behavioural and emotional problems in 24.5%. The report of behaviours associated with hyperactivity was high in 14.9% of the population and borderline in 18.1%. Adolescents with encephalopathy accounted for 44% of those whose total scores fell in either the abnormal and borderline ranges for emotional difficulties (p = .038).

CONCLUSION

Perinatally-acquired HIV-infected adolescents showed significant psychosocial and behavioural health risks that should bring attention to prevention and health care programmes. An earlier disclosure to children could favour a better psychological adjustment and a better treatment adherence. Future studies are needed to assess the relationship between vertically acquired HIV-infection and hyperactivity.

TNF-α levels in HIV-infected patients after long-term suppressive cART persist as high as in elderly, HIV-uninfected subjects

BACKGROUND

Chronic and systemic inflammatory alterations occur in HIV-infected patients and elderly uninfected subjects and in both scenarios these alterations are associated with the development of chronic morbidities and mortality. However, whether the levels of inflammatory alterations in untreated HIV-infected patients and elderly individuals are similar is unknown. Moreover, whether long-term antiretroviral therapy normalizes inflammatory alterations compared with HIV-uninfected persons of different age is not known.

METHODS

We analysed soluble inflammatory levels [high-sensitivity C-reactive protein, interferon (IFN)-γ, tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8 and IL-17] in a cohort of viraemic HIV-infected patients compared with (i) age-matched, (ii) elderly and (iii) non-survivor elderly, uninfected healthy controls. We longitudinally analysed the effect of long-term 48 and 96 week suppressive combined antiretroviral therapy (cART) on the soluble inflammatory levels compared with those found in control subjects.

RESULTS

Baseline IL-6 and IL-8 levels were at similar or lower concentrations in untreated patients compared with healthy elderly individuals. However, TNF-α and IFN-γ levels broadly exceeded those found in survivors and non-survivor elderly individuals. Long-term suppressive cART normalized most of the inflammatory markers, with the exception of TNF-α levels, which persisted as high as those in elderly non-survivor controls.

CONCLUSIONS

Chronic inflammatory alterations associated with HIV infection are maintained at a different level from those of ageing. The persistent alteration of TNF-α levels in HIV-infected patients might cause tissue damage and have implications for developing non-AIDS-defining illnesses, even when HIV replication is long-term controlled by cART.

Expression of gut-homing β7 receptor on T cells: surrogate marker for microbial translocation in suppressed HIV-1-infected patients?

OBJECTIVES

In view of the fact that mucosal damage associated with HIV-1 infection leads to microbial translocation despite successful antiretroviral treatment, we analysed microbial translocation and expression of the gut-homing β7 receptor on peripheral T cells in HIV-1-infected individuals.

METHODS

Fifteen long-term suppressed HIV-1-infected patients, of whom seven had their treatment intensified with maraviroc and eight with raltegravir, were included in the study. Samples at baseline, at week 48 of intensification, and at weeks 12 and 24 after deintensification were analysed for soluble CD14, lipopolysaccharide (LPS), LPS-binding protein, gut-homing β7 receptor and T-cell subsets.

RESULTS

The increases in both microbial translocation and expression of the gut-homing β7 receptor on activated CD8 T cells found during maraviroc intensification were reduced after deintensification. Moreover, the correlations between activated β7(+) T cells and LPS levels found during intensification with maraviroc (P = 0.036 and P = 0.010, respectively) were lost during deintensification. In contrast, microbial translocation was stable during raltegravir intensification, with the exception of decreased LPS levels and activated CD4 β7(+) T cells, which reverted to baseline values after deintensification.

CONCLUSIONS

Microbial translocation is an important factor in gut immune activation and mucosa inflammation, as evidenced by the association between the dynamics of microbial translocation and activated T cells expressing the gut-homing β7 receptor. The recruitment of activated β7(+) T cells to the gut tract when alteration of microbial translocation is maximum may be the major mechanism for recovery of mucosal integrity.

Maraviroc reduces the regulatory T-cell frequency in antiretroviral-naive HIV-infected subjects

BACKGROUND

Maraviroc is the first antiretroviral (ART) drug to target a human protein, the CCR5 coreceptor; however, the mechanisms of maraviroc-associated immunomodulation in human immunodeficiency virus (HIV)-infected subjects remain to be elucidated. Regulatory T cells (Tregs) play a key role in HIV-associated immunopathology and are susceptible to maraviroc-mediated CCR5 blockade. Our aim was to evaluate the effect of maraviroc on Tregs.

METHODS

We compared the effect of maraviroc-containing or -sparing combination ART (cART) on Tregs in ART-naive, HIV-infected subjects. Tregs were characterized as CD4(+)CD25(hi)FoxP3(+) on day 0, 8, and 30. Additional analysis on week 48 was performed in a subgroup of patients. The potential reduction in the frequency of Tregs among maraviroc-treated peripheral blood mononuclear cells (PBMCs) was also tested in vitro. The suppressive function of Tregs was also analyzed in maraviroc-treated Tregs.

RESULTS

We found that maraviroc significantly reduced the Treg frequency in both the short term and 1 year after treatment initiation. In vitro experiments showed a dose-dependent reduction in the Treg frequency after treatment of PBMCs with maraviroc, although their in vitro suppressive function was not altered.

CONCLUSIONS

These findings partially explain maraviroc-associated immunomodulatory effects and open new therapeutic expectations for the development of Treg-depleting immunotherapies.

Female sex hormones regulate the Th17 immune response to sperm and Candida albicans

STUDY QUESTION

What role do female sex hormones play in the antisperm immune response?

SUMMARY ANSWER

We found that sperm induce a Th17 immune response and that estradiol down-regulates the antisperm Th17 response by dendritic cells.

WHAT IS KNOWN ALREADY

Estradiol down-regulates the immune response to several pathogens and impairs the triggering of dendritic cell maturation by microbial products.

STUDY DESIGN, SIZE, DURATION

Ex vivo and in vivo murine models of vaginal infection with sperm and Candida albicans were used to study the induction of Th17 and its hormonal regulation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We analyzed the induction of Th17 cytokines and T cells in splenocytes obtained from BALB/c mice challenged with sperm and C. albicans. For the in vivo vaginal infection models, we used ovariectomized mice treated with vehicle, estradiol or progesterone, and we assessed the effect of these hormones on the immune response in the lymph nodes.

MAIN RESULTS AND THE ROLE OF CHANCE

Th17 cytokines and T cells were induced by sperm antigens in both ex vivo and in vivo experiments. Estrus levels of estradiol down-regulated the Th17 response to sperm and C. albicans in vivo.

LIMITATIONS, REASONS FOR CAUTION

This study was conducted using murine models; whether or not the results are applicable to humans is not known.

WIDER IMPLICATIONS OF THE FINDINGS

Our results describe an adaptive mechanism that reconciles immunity and reproduction and further explains why unregulated Th17 could be linked to infertility and recurrent infections.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by research grants from the Instituto de Salud Carlos III (ISCIII) (PI10/00897) and Fundación Mutua Madrileña to M.R. M.R. holds a Miguel Servet contract from the ISCIII (CP08/00228). M.A.M.-F. was supported by (ISCIII) INTRASALUD PI09/02029. We have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

Not required.

Validation of a generation 4 phosphorus-containing polycationic dendrimer for gene delivery against HIV-1

Gene therapy, in which oligomeric genetic material is carried into cells by nano-sized gene delivery vehicles to interfere with gene expression, represents a promising approach for preventive therapy against HIV/AIDS pandemic. Herein, we evaluate the usefulness of a phosphorus-containing dendrimer G4(NH+Et2Cl-)96 as a delivery agent of ODNs and siRNAs. G4(NH+Et2Cl-)96 formed stable complexes with ODNs or siRNAs and exhibited very low cytotoxicity in Sup T1 cells or PBMC. Functional validation was performed by using specific siRNA against HIV-1 Nef, siNEF to interfere in HIV-1 replication. G4(NH+Et2Cl-)96/siNEF dendriplex showed a high efficiency in Nef silencing. Furthermore, in vitro treatment of HIV-infected PBMC with G4(NH+Et2Cl-)96/siNEF dendriplex significantly reduced the viral replication. Our results prove the usefulness of phosphorus-containing dendrimers to deliver and transfect siRNA into CD4-T cells as a potential alternative therapy in the HIV-1 infection.

Specific patterns of CD4-associated immunosenescence in vertically HIV-infected subjects

Vertical transmission of human immunodeficiency virus (HIV) represents an important world-wide health problem although the incidence in developed countries has been drastically reduced by the extensive use of highly active antiretroviral therapy. Vertically HIV-infected subjects have been exposed to the virus during the maturation of their immune systems and have suffered a persistent chronic activation throughout their lifetime; the consequences of this situation for their immune system are not fully understood. The objective of this study was to analyse immunosenescence-related parameters in different CD4 T-cell subsets. Fifty-seven vertically HIV-infected subjects and 32 age-matched healthy subjects were studied. Activation (HLA(-) DR(+) ), senescence (CD28(-) CD57(+) ) and proliferation (Ki67(+) ) were analysed on different CD4 T-cell subsets: naive (CD45RA(+) CD27(+) ), memory (CD45RO(+) CD27(+) ), effector memory (CD45RO(+) CD27(-) ) and effector memory RA (CD45RA(+) CD27(-) ). Compared with healthy subjects, vertically HIV-infected subjects showed increased naive and memory CD4 T-cell frequencies (p 0.035 and p 0.010, respectively) but similar frequencies of both effector subsets. Whereas naive CD4 T cells were not further altered, memory CD4 T cells presented increased levels of senescence and proliferation markers (p <0.001), effector memory CD4 T cells presented increased levels of activation, senescence and proliferation markers (p <0.001) and effector memory RA CD4 T cells presented increased levels of activation and senescence (p <0.001) compared with healthy subjects. Despite long periods of infection, vertically HIV-infected subjects show specific patterns of immunosenescence, revealing a preserved CD4 T-cell homeostasis for subset differentiation and distribution. Nevertheless, excepting the naive subpopulation, all subsets experienced some immunosenescence, pointing to uncertain consequences of the future aging process in these subjects.

Carbosilane dendrimers to transfect human astrocytes with small interfering RNA targeting human immunodeficiency virus

BACKGROUND

HIV infection of the CNS is the principle cause of HIV-associated dementia in adults and encephalopathy in children. Gene therapy techniques such as small interfering RNA (siRNA) possess great potential in drug development, but first they must overcome the key obstacle of reaching the interior of the affected cells. A successful delivery vector for anti-HIV drugs that is capable of crossing the blood-brain barrier (BBB) could provide a way of addressing this issue. Non-viral vectors such as dendrimers offer a means for effectively delivering and transfecting siRNA to the target cells.

OBJECTIVE

To evaluate the application of gene therapy for reducing HIV replication in human astrocytes.

METHODS

We used the 2G-NN16 amino-terminated carbosilane dendrimer as a method for delivering siRNA to HIV-infected human astrocytes. We tested the cytotoxicity in human astrocytoma cells caused by 2G-NN16 and dendriplexes formed with siRNA (siRNA/2G-NN16) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium-bromide (MTT) and lactate dehydrogenase assays. The ability to transfect human astrocytes with siRNA/2G-NN16 dendriplexes was tested by flow cytometry and immunofluorescence microscopy. To assess the potential capability of siRNA/2G-NN16 dendriplexes for crossing the BBB, we used an in vitro transcytosis assay with bovine brain microvascular endothelial cells. HIV-1 inhibition assays using 2G-NN16 and siRNA/2G-NN16 dendriplexes were determined by quantification of the viral load from culture supernatants of the astrocytes.

RESULTS

A gradual time-controlled degradation of the 2G-NN16 dendrimer and liberation of its siRNA cargo between 12 and 24 hours was observed via gel electrophoresis. There was no cytotoxicity in HIV-infected or non-infected human astrocytoma cells when treated with up to 24 microg/mL of 2G-NN16 dendrimer or siRNA/2G-NN16 dendriplexes, and siRNA/2G-NN16 dendriplexes were seen to successfully transfect human astrocytes even after crossing an in vitro BBB model. More interestingly, transfected siRNA was observed to exert a biologic effect, as dendriplexes were shown to down-regulate the housekeeping gene GAPDH and to reduce replication of HIV-1 strains X4-HIV NL4-3 and R5-HIV BaL in human astrocytes.

CONCLUSIONS

The 2G-NN16 dendrimer successfully delivers and transfects siRNA to HIV-infected human astrocytes and achieves gene silencing without causing cytotoxicity.

Comparison of levels of antiretroviral drugs with efficacy in children with HIV infection

OBJECTIVE

To determine the prevalence of low and high antiretroviral (ARV) plasma levels and to analyze correlation between ARV concentrations and the appearance of therapeutic failure and toxicity.

METHODS

The authors present here a study evaluating antiretroviral plasma concentrations in HIV infected children on nonnucleoside reverse transcriptase inhibitors and protease inhibitors based therapy. The authors carried out a multicentre, cross-sectional study, including HIV-infected children from five large Hospitals in Madrid, Spain. Clinical, haematological, biochemical and immuno-virological parameters were assessed. Antiretroviral plasma trough levels were performed using a validated high performance liquid chromatography method.

RESULTS

Between April 2006 and April 2008, 129 children were enrolled in the present study, with median treatment duration of 39.2 months. 25.5% of the non-nucleoside reverse transcriptase inhibitors levels were low and 17.6%, high. 27.9% percent of the protease inhibitors levels were low and 12.5%, high. A correlation was found among adequate or high levels of antiretrovirals and normal CD4 percentage and low viral load. Lopinavir/ritonavir plasma levels were correlated with an increase in lipodystrophy. Patients with Tanner stage 1 presented the lowest ARV plasma levels. Full adherence was reported for all the participants by a questionnaire.

CONCLUSION

Many HIV-infected children show ARV plasma levels out of the therapeutic range which demands a child-adjusted approach. However, larger studies are urgently needed in pediatric populations to define optimal reference values.

Premature immunosenescence in HIV-infected patients on highly active antiretroviral therapy with low-level CD4 T cell repopulation

OBJECTIVES

To analyse the role of thymic function and its association with cellular immunosenescence markers in patients with low-level CD4 T cell repopulation, despite complete HIV RNA replication control on highly active antiretroviral therapy (HAART).

METHODS

Cellular immunosenescence markers comparing patients with CD4 T cell counts <or=250 cells/mm(3) for >or=48 weeks (n = 11) and patients with a CD4 T cell count >or=500 cells/mm(3) (n = 11) were investigated. Both groups were also compared with 11 healthy volunteers of similar age. Naive CD4 T cell counts, beta- and delta-T cell rearrangement excision circles, recent thymic emigrants, replicative senescence marker, cell activation, and rate of apoptosis were analysed. The Mann-Whitney U-test was used to compare parameters between both low-level and high-level CD4 T cell repopulation groups, and healthy volunteers.

RESULTS

Our results showed a lower thymic activity in patients with low-level CD4 T cell repopulation, leading to a decline in CD4 T cell production. On the other hand, a higher activation along with a higher replicative senescence of CD4 T cells contributed to a higher rate of apoptotic CD4 T cells in this group of patients.

CONCLUSIONS

We propose a model with several different related mechanisms involved in premature immune senescence in HIV-infected patients with low-level CD4 repopulation on HAART. The understanding of such different mechanisms could help find effective strategies to prevent immune decay.

Expression of a modified form of CD4 results in the release of an anti-HIV factor derived from the Env sequence

We have studied the inhibitory effect of a CD4 chimera (CD4epsilon15) on HIV replication. This chimera is retained in the endoplasmic reticulum and traps the HIV envelope precursor gp160, preventing its maturation. Retroviral expression of the chimera strongly inhibited HIV replication even when it is expressed by only a minority of the T cell population. This protective effect on bystander nontransduced cells is mediated by a soluble factor that we identified as a fragment of HIV gp120 envelope protein and accordingly, we named this factor Env-derived antiviral factor (EDAF). Biochemical and immunoreactivity data show that EDAF is comprised of the gp120 C3-C5 regions and indeed, a recombinant protein bearing this sequence reproduces the anti-HIV properties of EDAF. Surprisingly, three tryptic peptides derived from EDAF are homologous but not identical with the corresponding sequences of the HIV isolate used to generate EDAF. We propose that EDAF results from an alternative intracellular processing of the Env protein provoked by its association to CD4epsilon15 and the selection of the best fitted Env protein sequences contained within the HIV isolate. The presence of EDAF improves the therapeutic potential of the CD4epsilon15 gene and it opens new possibilities for antiviral treatment and vaccine development.

Socio-economic impact of antiretroviral treatment in HIV patients. An economic review of cost savings after introduction of HAART

Star celebrities such as Rock Hudson, Freddie Mercury, Magic Johnson, and Isaac Asimov have unfortunately something in common: they were all victims of the HIV global pandemic. Since then HIV infection has become considered a pandemic disease, and it is regarded as a priority in healthcare worldwide. It is ranked as the first cause of death among young people in industrialized countries, and it is recognized as a public healthcare problem due to its human, social, mass media, and economic impact. Incorporation of new and highly active antiretroviral treatment, available since 1996 for HIV/AIDS treatment, has provoked a radical change in the disease pattern, as well as in the impact on patient survival and quality of life. The pharmaceutical industry's contribution, based on the research for more active new drugs, has been pivotal. Mortality rates have decreased significantly in 20 years by 50% and now AIDS is considered a chronic and controlled disease. In this review we have studied the impact of HAART treatment on infected patients, allowing them to maintain their status as active workers and the decreased absenteeism from work derived from this, contributing ultimately to overall social wealth and, thus, to economic growth. Furthermore, an analysis of the impact on healthcare costs, quality of life per year, life per year gained, cost economic savings and cost opportunity among other parameters has shown that society and governments are gaining major benefits from the inclusion of antiretroviral therapies in HIV/AIDS patients.

Serum levels of fibrosis biomarkers measured early after liver transplantation are associated with severe hepatitis C virus recurrence

This prospective study analyzed the relationship between several biological markers related to liver fibrosis at 3 months and 1 year post liver transplantation in 37 patients (19 with hepatitis C virus [HCV], 18 with alcoholic liver disease). Severe HCV recurrence (HCV-SR) was defined as fibrosis stage > or =F1 (METAVIR score) at 1 year and/or a value of hepatic venous pressure gradient > or=6 mmHg. We found HCV-SR patients had higher values of monocyte chemotactic protein-1 (MCP-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and hyaluronic acid (HA) than non-severe HCV recurrence patients (P<0.05). Moreover, receiver operating characteristic curve analysis showed that interferon-inducible protein 10 (IP-10) (area under the curve [AUC]: 0.74; confidence interval [CI] 95%: 0.49-0.91; P=0.043), MCP-1 (AUC: 0.78; CI 95%: 0.54-0.94; P=0.007), sVCAM-1 (AUC: 0.89; CI 95%: 0.67-0.98; P=0.005), and HA (AUC: 0.80; CI 95%: 0.55-0.94; P=0.035) have good predictive capacity for identifying severe HCV infection. The evaluation of these biomarkers may be useful in the early identification of patients in whom a more aggressive therapeutic approach could be necessary.

Highly efficient transfection of rat cortical neurons using carbosilane dendrimers unveils a neuroprotective role for HIF-1alpha in early chemical hypoxia-mediated neurotoxicity

PURPOSE

To study the effect of a non-viral vector (carbosilane dendrimer) to efficiently deliver small interfering RNA to postmitotic neurons to study the function of hypoxia-inducible factor-1alpha (HIF1-alpha) during chemical hypoxia-mediated neurotoxicity.

METHODS

Chemical hypoxia was induced in primary rat cortical neurons by exposure to CoCl(2). HIF1-alpha levels were determined by Western Blot and toxicity was evaluated by both MTT and LDH assays. Neurons were incubated with dendriplexes containing anti-HIF1-alpha siRNA and both uptake and HIF1-alpha knockdown efficiency were evaluated.

RESULTS

We report that a non-viral vector (carbosilane dendrimer) can deliver specific siRNA to neurons and selectively block HIF1-alpha synthesis with similar efficiency to that achieved by viral vectors. Using this method, we have found that this transcription factor plays a neuroprotective role during the early phase of chemical hypoxia-mediated neurotoxicity.

CONCLUSION

This work represents a proof-of-concept for the use of carbosilane dendrimers to deliver specific siRNA to postmitotic neurons to block selected protein synthesis. This indicates that this type of vector is a good alternative to viral vectors to achieve very high transfection levels in neurons. This also suggests that carbosilane dendrimers might be very useful for gene therapy.

PI4P5-kinase Ialpha is required for efficient HIV-1 entry and infection of T cells

HIV-1 envelope (Env) triggers membrane fusion between the virus and the target cell. The cellular mechanism underlying this process is not well known. Phosphatidylinositol 4,5-bisphosphate (PIP(2)) is known to be important for the late steps of the HIV-1 infection cycle by promoting Gag localization to the plasma membrane during viral assembly, but it has not been implicated in early stages of HIV-1 membrane-related events. In this study, we show that binding of the initial HIV-1 Env-gp120 protein induces PIP(2) production in permissive lymphocytes through the activation of phosphatidylinositol-4-phosphate 5-kinase (PI4P5-K) Ialpha. Overexpression of wild-type PI4P5-K Ialpha increased HIV-1 Env-mediated PIP(2) production and enhanced viral replication in primary lymphocytes and CEM T cells, whereas PIP(2) production and HIV-1 infection were both severely reduced in cells overexpressing the kinase-dead mutant D227A (D/A)-PI4P5-K Ialpha. Similar results were obtained with replicative and single-cycle HIV-1 particles. HIV-1 infection was also inhibited by knockdown of endogenous expression of PI4P5-K Ialpha. These data indicate that PI4P5-K Ialpha-mediated PIP(2) production is crucial for HIV-1 entry and the early steps of infection in permissive lymphocytes.

Extracellular HIV-Tat induces cyclooxygenase-2 in glial cells through activation of nuclear factor of activated T cells

Both the HIV-1 protein Tat and cyclooxygenase-2 (COX-2) have been involved in the neuropathogenesis associated with HIV-1 infection. However, the relationship among them has not been addressed. Here, we found that extracellular Tat was able to induce COX-2 mRNA and protein expression and PGE2 synthesis in astrocytoma cell lines and primary human astrocytes. Moreover, Tat induced COX-2 promoter transcription. Deletion of NF-kappaB sites of the promoter did not diminish Tat-dependent transcription. Interestingly, Tat did not induce NF-kappaB activity, suggesting that NF-kappaB was not necessary to control COX-2 transcription induced by Tat. In contrast, deletion or mutation of the NFAT and/or AP-1 site abrogated COX-2 induction by Tat. Moreover, Tat induced transcription of NFAT- and AP-1-dependent reporter genes. Transfection of a dominant negative c-Jun mutant protein, TAM-67, or of a dominant negative version of NFAT, efficiently blocked the induction of COX-2 promoter by Tat, confirming the requirement of both transcription factors. Moreover, Tat induced NFAT translocation to the nucleus and binding to the distal site of the COX-2 promoter. The importance of NFAT and AP-1 in COX-2 induction and PGE2 synthesis by Tat was corroborated by using pharmacological inhibitors of the NFAlphaTau, ERK, and JNK pathways. In summary, our results indicate that HIV-1 Tat was able to induce COX-2 and PGE2 synthesis in astrocytic cells through an NFAT/AP-1-dependent mechanism.

NK cell increase in neonates from the preterm to the full-term period of gestation

BACKGROUND

Several studies have reported differences in lymphocyte phenotype in preterm and full-term neonates as compared to children and adults. However, a detailed description of the immunologic cell populations of neonates corresponding to the gestational age is needed. This will be helpful for clinical practice to find the best way to prevent neonatal infections or strengthen the immune system of newborns with some kind of immunodeficiency.

OBJECTIVE

To study maturation of the immune system throughout gestation, describing the variations of the lymphocyte populations in function of the gestational week when born.

METHODS

We performed a descriptive study in 134 healthy newborns (gestation age 25-42 weeks), quantifying the relative and absolute counts of cell populations in umbilical cord blood obtained during delivery, by a four-color flow cytometry single platform.

RESULTS

We first compared the very-preterm (25-30 weeks), preterm (31-36 weeks) and full-term (37-42 weeks) neonates. We found higher absolute counts of all cell populations in the full-term group and lower absolute and relative values of NK cells in the very-preterm group. After that, we analyzed the lymphocyte populations week to week (from week 31 to 41) and found the lowest values of T cells (CD4+ and CD8+) for week 36. However, lower percentages of CD4+ T cells and higher percentages of NK cells were observed in week 38 and 41.

CONCLUSION

We found an increase in cord blood NK cells with gestational age, both in terms of absolute counts and of percentage values. Moreover, the %NK cells showed a pattern opposite to %CD4+ T cells along the studied period.

[False negative diagnosis of HIV-1]

We report a case of a false negative diagnosis of HIV-1 infection in an African girl. Two HIV-1 DNA polymerase chain reaction (PCR) tests were negative at the second and fourth months of life. Because anti-HIV antibodies persisted when the patient was 18 months old, the HIV-1 RNA PCR test was performed with a positive result, confirming HIV-1 non-B subtype, recombinant A-G. The prevalence of non-B HIV-1 subtypes are increasing in Spain, which could be related to the phenomenon of immigration. Approximately one-third of HIV-infected foreigners have non-B subtypes and the percentage increases to 70 % of the African population in Spain. In non-B HIV-1 subtypes, false negative results and inconsistencies between viral load and CD4 count are more frequent. These subtypes also show a higher rate of resistance to protease inhibitors, which can have therapeutic implications.

Safety and antiviral response at 12 months of lopinavir/ritonavir therapy in human immunodeficiency virus-1-infected children experienced with three classes of antiretrovirals

INTRODUCTION

Many human immunodeficiency virus type 1 (HIV-1)-infected children have already failed treatment with 2 or even 3 classes of antiretrovirals. Coformulation of lopinavir with low dose ritonavir exhibits a potent antiretroviral effect. However, the data in heavily pretreated children are still scarce. This study evaluated the safety and effectiveness of combination therapy including lopinavir/ritonavir in children with prior exposure to all classes of oral antiretrovirals.

METHODS

This was an open label multicenter observational study, in which data were reviewed according to a standardized protocol. The study population included all HIV-1-infected children with virologic failure (HIV-1 RNA >5000 copies/mL) followed in 12 Spanish hospitals for >12 months, experienced with the 3 classes of oral antiretrovirals, in whom a lopinavir/ritonavir-containing regimen was started.

RESULTS

By March 2003, 45 patients had been treated with lopinavir/ritonavir for a median of 18 months (range, 3-28). The median age at baseline was 9.7 years (range, 4.3-17.1). The median times of prior treatment were 88 months (range, 31-145) with nucleoside reverse transcription inhibitors and 42 months (range, 19-63) with protease inhibitors. Twenty-five patients were classified as Centers for Disease Control and Prevention clinical category C. Median values for absolute and percentage CD4 at baseline were 501 (range, 6-1512) and 19% (range, 0.5-49), respectively, and plasma HIV-RNA was 5.0 log10 copies/mL (range, 4.1-6.1). During follow-up, 11 (24%) children switched from liquid to solid formulation. At 48 weeks, the median values for absolute and percentage CD4 increased by 199 cells/microL and 3%, respectively, and median plasma viral load declined 1.75 log10 copies/mL. Forty-two percent of children achieved a plasma RNA of <400 copies/mL (intent to treat analysis). Baseline genotypic resistance was available in 40 children. Nonresponders had 7.0 +/- 1.6 protease inhibitor-associated mutations at baseline compared with 4.8 +/- 1.7 in children achieving virologic suppression (P = 0.06). Adverse events were described in 18 children. Three children permanently discontinued and 4 transiently withdrew lopinavir/ritonavir. At 12 months, there were mild but not significant increases in plasma cholesterol and triglycerides.

CONCLUSIONS

Lopinavir/ritonavir when given as part of salvage regimen is well-tolerated, although switching to pills is frequently required. The regimen has a potent and durable antiretroviral activity in most heavily pretreated children, despite the presence of multiple mutations to all classes of oral antiretrovirals.

Situación actual en el desarrollo de una vacuna preventiva frente al VIH

El avance de la epidemia de sida ha convertido la obtención de una vacuna eficaz frente al virus de la inmunodeficiencia humana (VIH) como un objetivo científico prioritario. En el momento actual no disponemos de una vacuna preventiva frente a la infección por el VIH y en ningún modelo animal se ha conseguido la protección frente a la infección. En esta revisión se analizan las dificultades existentes en el desarrollo de una vacuna contra el sida, en especial los mecanismos de escape viral a la respuesta inmunitaria y se describen los prototipos de vacunas preventivas y terapéuticas en desarrollo y los resultados obtenidos. Por otra parte se sitúa esta investigación en el contexto sanitario, económico y social de la pandemia de sida y se analizan las polémicas actualmente planteadas en el desarrollo de ensayos clínicos con los diferentes tipos de vacunas.

Recomendaciones CEVIHP/SEIP/AEP/PNS respecto al tratamiento antirretroviral en niños y adolescentes infectados por el VIH

OBJECTIVE

To update antiretroviral recommendations in antiretroviral therapy (ART) in HIV-infected children and adolescents.

METHODS

Theses guidelines have been formulated by a panel of members of the Plan Nacional sobre el SIDA (PNS) and the Asociacion Espanola de Pediatria (AEP) by reviewing the current available evidence of efficacy, safety, and pharmacokinetics in pediatric studies. Three levels of evidence have been defined according to the source of data: Level A: randomized and controlled studies; Level B: Cohort and case-control studies; Level C: Descriptive studies and experts' opinion.

RESULTS

When to start ART should be made on an individual basis, discussed with the family, considering the risk of progression according to age, CD4 and viral load, the ART-related complications and adherence. The ART goal is to reach a maximum and durable viral suppression. This is not always possible, even with clinical and immunologic improvement. The difficulties of permanent adherence and side-effects are resulting in a more conservative trend to initiate ART, and to less toxic and simpler strategies. Currently, combinations of at least three drugs are of first choice both in acute and chronic infection. They must include 2 NA 1 1 NN or 2 NA 1 1 PI. ART is recommended in all symptomatic patients and, with few exceptions, in all infants in the first year of life. Older asymptomatic children should start ART according to CD4 count, especially CD4 percentage, that vary with age. Despite potent salvage therapies, it is common not to reach viral undetectability. Therapeutical options when ART fails are scarce due to cross-resistance. The cause of failure must be identified. Occasionally, there exists clinical and/or immunological progression, and a change of therapy with at least two new drugs still active for the patient, is warranted with the aim of increasing the CD4 count to a lower level of risk. Toxicity and adherence must be regularly monitored. Some aspects about post exposure prophylaxis and coinfection with HCV or HBV are discussed.

CONCLUSIONS

A higher level of evidence with regard to ART effectiveness and toxicity in pediatrics is currently available, leading to a more conservative and individualized approach. Clinical symptoms and CD4 count are the main determinants to start and change ART.

Preserved immune system in long-term asymptomatic vertically HIV-1 infected children

The objective of this study was to study immune system status in long-term asymptomatic (LTA) HIV-1-infected children. A cross-sectional study was used, involving HIV-1-infected children over 7 years of age who were rated into two groups according to their clinical and immunological classification: (a) LTA: 7 asymptomatic HIV-1-infected children in A1; (b) Rapid progressor (RP): 14 age-matched C3 HIV-1-infected children. The control group consisted of 17 age-matched uninfected children. The characterization of CD4+ T-cell subsets was determined by three-colour flow cytometry. The proliferative response and cytokine production by activated peripheral blood T-cells were also measured. IL-7 levels were measured in serum. Thymic production of T-cells was quantified by TCR rearrangement excision circles (TRECs). The LTA children showed similar proliferative responses to PHA, PWM and anti-CD3+ anti-CD28, but lower responses to tetanus toxoid and streptokinase, in comparison with the controls but always higher responses in comparison with the RP group. The production of TNF-alpha and IFN-gamma was similar in the LTA and control groups, and both were higher than the levels in the RP group. The LTA group showed a lower percentage of memory CD4+ T-cells (CD4+ CD45RO+, CD4+ CD45RA-CD62L+) than the control and RP groups. The LTA group also showed lower percentages of CD4+ CD7- cells than the controls. As for naïve CD4+ T-cells (CD4+ CD45RA+ CD62L+), CD4+ CD45RA+ and CD4+ CD62L+ cells, the LTA group showed higher values than the control and RP groups. The LTA group showed higher percentages of CD4+ HLA-DR+ CD38+ than the controls, but lower values than the RP group. In contrast, the LTA group had percentages of CD4+ HLA-DR-CD38+ T-cells higher than both the control and RP groups, whereas CD4+ CD38+ levels were only higher in the LTA group in comparison with the controls. CD4+ HLA-DR+ CD38- and CD4+ HLA-DR+ cell numbers were lower in the LTA group in comparison with the RP group. We found almost normal values of TRECs and IL-7 in the LTA group, but lower values in the RP group. Moreover, we found an inverse relation between TREC levels and IL-7 in plasma from HIV-infected children. Asymptomatic HIV-1 infected children have a well preserved immune system similar to that of control uninfected children in spite of HIV-infection for more than 7 years. Moreover, our results identified new markers of HIV disease, such as TRECs and IL-7, that could be used to monitor disease.

Undetectable levels of tumor necrosis factor-alpha, nitric oxide and inadequate expression of inducible nitric oxide synthase in congenital hypothyroidism

OBJECTIVE

To analyse the production of TNF-alpha and NO in euthyroid and hypothyroid newborns.

PATIENTS

A cross-sectional study was conducted involving 10 newborns diagnosed with primary congenital hypothyroidism (CH; group A) and 10 euthyroid children (group B).

RESULTS

There were undetectable plasma levels of TNF-alpha and NO in the hypothyroid children, however plasma levels of TNF-alpha (5.5 0.5 pg/ml) and NO (5.6 1.7 microM) were detected at normal levels in all euthyroid children. Moreover, expression of iNOS mRNA in PBMC, determined by RT-PCR, was negative in both groups of infants.

CONCLUSION

TNF-alpha and NO production are both impaired in hypothyroid newborns. We report for the first time evidence of undetectable levels of TNF-alpha and NO in infants with CH.

Candida albicans infection enhances immunosuppression induced by cyclophosphamide by selective priming of suppressive myeloid progenitors for NO production

Systemic infections caused by fungi after cytoreductive therapies are especially difficult to deal with in spite of currently available antimicrobials. However, little is known about the effects of fungi on the immune system of immunosuppressed hosts. We have addressed this by studying the in vitro T cell responses after systemic infection with Candida albicans in cyclophosphamide-treated mice. After cyclophosphamide treatment, a massive splenic colonization of the spleens, but not lymph nodes, by immature myeloid progenitor (Ly-6G(+)CD11b(+))cells is observed. These cells are able to suppress proliferation of T lymphocytes via a nitric oxide (NO)-dependent mechanism. Systemic infection with a sublethal dose of C. albicans did not cause immunosuppression per se but strongly increased NO-dependent suppression in cyclophosphamide-treated mice, by selective priming of suppressive myeloid progenitors (Ly-6G(+)CD11b(+)CD31(+)CD40(+)WGA(+)CD117(low/-)CD34(low/-)) for iNOS protein expression. The results indicate that systemic C. albicans infection can augment the effects of immunosuppressive therapies by promoting functional changes in immunosuppressive cells.

[T-cell subsets variation during clinical and immunological progression in vertically HIV-infected children]

We have investigated the relationship among peripheral blood T-cell subsets with immunological and clinical categories, and viral load (VL) in 65 HIV-1-infected children on stable antiretroviral therapy (ART): 26 (40%) children on combination therapy with 2 nucleoside inhibitors, and 39 (60%) children on highly active antiretroviral therapy (HAART). T-cell subsets were determined by flow cytometry. VL was quantified using a standardized molecular method. Naïve CD4+ T-cells (CD45RA+CD62L+) were lower in children with low %CD4+ T-cells, but neither in children with advanced stage of illness nor with high VL. By contrast, naïve CD8+ T-cells were lower in children with low %CD4+ T-cells, advanced stage of illness and high VL. Memory (CD45RO+) and activated (CD38+, HLA-DR+ and CD38+HLA-DR+) CD4+ and CD8+ T-cells were higher in children with low %CD4+ T-cells, advanced stage of illness and high VL. However, CD4+CD38+ T-cells were higher in HIV-children with CD4+ > 25% than in the control group (p < 0.001) and were diminished in children with low %CD4+ T-cells. Naïve and memory CD4+ and CD8+ T-cells are more tightly dependent on the immunological category than on clinical category or plasma VL. Furthermore, our data indicate an association between low %CD4+ T-cells, high VL and high expression of cellular activation markers, although not with advanced clinical stage, possibly due to ART.

Antibodies to an epitope from the Cha human autoantigen are markers of Chagas' disease

Chagas' disease is a prevalent disease in South America that is thought to have an autoimmune etiology. We previously identified human Cha as a new autoantigen recognized by chagasic sera. Those sera recognized an epitope spanning amino acids 120 to 129 of Cha, named R3. In the present study we have used the synthetic R3 peptide for the detection of serum immunoglobulin G antibodies from patients at different stages of Chagas' disease, including a therapeutically treated group. The immunoreactivity with R3 by enzyme-linked immunosorbent assay (ELISA) showed 92.4% sensitivity and 100% specificity for Chagas' disease sera. This sensitivity and specificity were higher than for any other autoantigen described to date. No anti-R3 antibodies were detected in sera from Leishmania-infected or idiopathic dilated cardiomyopathy patients or healthy controls from the same areas. Moreover, anti-R3 antibody reactivity detected by ELISA correlated with conventional serological tests as indirect immunofluorescence and ELISA assays with Trypanosoma cruzi extracts and other diagnostic tests as indirect hemagglutination. The levels of anti-R3 antibodies increased with progression and symptomatology of Chagas' disease. More interestingly, a statistically significant fall in anti-R3 antibody titer was observed in patients treated with antiparasitic drugs. Those results suggest that the presence of anti-R3 antibodies is a highly specific marker of Chagas' disease and that R3 ELISA could be helpful in the diagnosis and monitoring of this disease.

Phosphodiesterase 4 inhibitors prevent cytokine secretion by T lymphocytes by inhibiting nuclear factor-kappaB and nuclear factor of activated T cells activation

Blockade of phosphodiesterase 4 with rolipram reduced the production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-5, IL-10, and IL-2 but poorly inhibited cell proliferation and interferon-gamma (IFN-gamma) production by activated human T cells. Addition of dibutyryl cAMP mimicked rolipram inhibitions on proliferation, IL-2, TNF-alpha, and IFN-gamma but not on IL-10 or IL-5 production. Moreover, the inhibitory effects of rolipram on proliferation, IFN-gamma, and TNF-alpha but not of IL-10 production can be prevented by a specific protein kinase A inhibitor. Rolipram and pentoxifylline, a nonspecific phosphodiesterase inhibitor, decreased transcription of IL-2 and TNF-alpha promoters in transiently transfected normal T cells. Moreover, they inhibited the activation of nuclear factor-kappaB (NF-kappaB) and nuclear factor of activated T cells (NFAT) and stimulated activator protein-1 (AP-1) and cAMP response element-binding proteins (CREBs). In contrast, dibutyryl cAMP inhibited NF-kappaB but not NFAT activation. Thus, our data indicate that blockade of phosphodiesterase 4 regulates transcription of a particular cytokine through inhibition of NF-kappaB and NFAT, and stimulation of AP-1 and CREB.

Viral phenotype affects the thymic production of new T cells in HIV-1-infected children

OBJECTIVE

To determine whether viral phenotype has any effect on thymic production of new T cells in HIV-1-infected children.

DESIGN

Differences in CD4+ T-cell counts and a marker of thymic output [T-cell antigen receptor (TCR) rearrangement excision circles (TRECs)], between HIV-1-infected children with non-syncytium-inducing (NSI) and syncytium-inducing (SI) viral strains were determined.

PATIENTS AND METHODS

A cross-sectional study in 90 samples from vertically HIV-1-infected-children (median age 4.9 years) treated with combination therapy, and a longitudinal study in three children that underwent a change from NSI to SI phenotype were carried out. Viral load, viral phenotype, CD4+ T-cell counts, and quantification of TRECs values were determined.

RESULTS

Children with SI virus showed significant lower levels of CD4+ T cells and a lower thymic production of new T cells than children with NSI. These reductions were independent of the treatment and the age of the children. However, there were no differences in viral load with the phenotype between those groups. In children with both NSI and SI viral phenotype, there was a significant correlation between CD4+ T-cell counts and TRECs values.

CONCLUSION

The decrease of CD4+ T cells in presence of T-tropic viruses would be mainly due to a lower production of new CD4+ T cells as consequence of the inhibitory effect of these T-tropic strains on thymic function. This effect is not due either to the amount of circulating virus or to the replication kinetics of those strains, but rather depends on the ability of T-tropic viruses to infect T-cell precursors using CXCR4 receptors, which are highly expressed in immature thymocytes.

Disruption in cytokine and chemokine production by T-cells in vertically HIV-1-infected children

This study measured cytokine production by mitogen-stimulated peripheral blood mononuclear cells (PBMCs) from 55 human immunodeficiency virus (HIV)-infected children born to HIV-infected mothers, and compared it with vertically exposed but uninfected age-matched children. A significant defect was observed in Th1 cytokine production [interferon-gamma and interleukin-2 (IL-2)] in HIV-infected children compared with controls, but without a concomitant increase in Th2 cytokines. Indeed, IL-5 and IL-10 production was even lower in HIV-infected children than in controls, with the decrease in IL-5 being the best predictive marker of immunodeficiency. In addition, an increased release of tumour necrosis factor-alpha (TNF-alpha) that correlated well with CD4+ levels, and a positive correlation of the TNF-alpha/IL-10 ratio with disease progression was observed. A correlation between AIDS-free status and higher %CD4+ and %CD8+ T-lymphocytes and RANTES (regulated on activation, normal T-cell expressed and secreted) production was also found.

CONCLUSION

A dysfunctional cytokine production of PBMCs was observed in HIV-infected children in both Th1 and Th2 cytokines due to quantitative and qualitative defects induced by HIV-1. An important observation was an increased RANTES production associated with viral isolates of NSI/R5 phenotype and S/L kinetics.

Naïve and memory CD4+ T cells and T cell activation markers in HIV-1 infected children on HAART

The objective of this study was to investigate the relationship between peripheral blood CD4+ T cell subsets and routine viro-immunological markers in vertically HIV-1-infected children undergoing highly active antiretroviral therapy (HAART). CD4+ and CD8+ T cell subsets were examined by three-colour flow cytometry. Plasma viraemia was quantified by a standardized molecular assay. A negative correlation between the %CD4+ T cells and both viral load and the %CD8+ T cells was observed. A strong positive correlation between the %CD4 T cells and naïve, CD38+ and non-activated CD4+ T cell subsets was found, whereas the %CD4 T cells correlated negatively with the numbers of memory, activated and memory-activated CD4+ T cell subsets. Elevated percentages of CD8 T cells were associated with increased memory and CD4+ CD62L-T cell subsets, whereas the naïve and CD4+ HLA-DRCD38+ subsets negatively correlated with the CD8%. Co-expression of CD62L on memory CD4+ cells and high expression of HLA-DR (but not of CD38) were associated with high viral load. No association between viral load and naïve CD4+ T cells was observed. Specific CD4+ T cell subsets may be more informative than routine surrogate markers in defining the evolution of HIV infection and immune reconstitution in children.

[Relationship between T-cells subsets and prognostic markers in HIV-1-infected children]

BACKGROUND

To investigate the relationship between peripheral blood T-cell subsets and both CD4+ T-cell percentage and viral load (VL) in HIV-1-infected children.

PATIENTS AND METHOD

We studied 50 HIV-1-infected children on antiretroviral therapy. T-cell subsets were determined by flow cytometry. The VL was quantified using standardized molecular methods.

RESULTS

Memory (CD45RO+), activated memory (CD45RO+HLA-DR+) and CD45RA-CD62L+ (memory cells expressing L-selectin) CD4+ and CD8+ T-cells correlated positively with the VL and negatively with the percentage of CD4+ T-cells. Inversely, naive CD4+ and CD8+ T-cells (CD45RA+CD62L+) correlated positively with the percentage of CD4+ T-cells and negatively with the VL. HLA-DR+, CD38+ or HLA-DR+CD38+CD4+ and CD8+ T-cells correlated also positively with the VL and negatively with the percentage of CD4+ T-cells (with the exception of CD4+CD38+ which did not show any association with the VL). CD8+CD28+ T-cells correlated positively with the percentage of CD4+ T-cells and negatively with the VL, whereas CD8+ CD57+ and CD8+CD28-CD57+ exhibited an opposite association.

CONCLUSIONS

Our data suggest a relationship between the different lymphocyte subsets (memory, naïve, activated and effector T-cells) and the most commonly used markers in clinical practice, namely the viral load and the CD4+ T-cell percentage. Some of these subsets may be useful to determine the virologic and immunologic status in HIV-1-infected children.

Tumor necrosis factor-alpha and nitric oxide in vertically HIV-1-infected children: implications for pathogenesis

We performed a cross-sectional study to investigate the plasma TNF-alpha and nitric oxide (NO) production in 44 vertically HIV-1-infected children, and the relationship with immunological status and viral replication. As a control group, 36 healthy, uninfected children were studied. Plasma TNF-alpha and NO levels were determined by ELISA. Viral load was quantified using standard assays. Cell proliferation, apoptosis and viral replication were evaluated in vitro by incorporation of (3H)-thymidine, flow cytometry and p24 antigen, respectively. Higher plasma TNF-alpha and NO levels were observed in HIV-1-infected children compared with healthy controls. We found a very strong correlation between plasma TNF-alpha and NO levels in HIV-1-infected children (r = 0.98; p < 0.001). Moreover, HIV-1-infected children with higher viral load (> 4.7 log10) showed higher TNF-alpha and NO levels than those with viral load below this threshold. Interestingly, we detected inducible nitric oxide synthase (iNOS) mRNA in T-lymphocytes from HIV-1-infected children. To address their possible patho-physiological significance, we tested the in vitro effects of NO and TNF-alpha in HIV-1 replication. Addition of TNF-alpha and NO donors to mitogen-activated, HIV-1-infected PBMC cultures produced a significant increase in viral replication. Moreover, HIV-1 replication in mitogen-stimulated, PBMC cultures was partially inhibited by iNOS specific inhibitors, and a neutralising, anti-TNF-alpha monoclonal antibody. Our results indicate that TNF-alpha and NO correlated with high viral load in HIV-1-infected children and favoured HIV-1 in vitro replication. These data suggest a detrimental role of NO in HIV-1 infection, and that NOS inhibitors may have some therapeutic benefit in HIV-1-infection.

Regulation of human immunodeficiency virus type 1 replication in human T lymphocytes by nitric oxide

Addition of nitric oxide (NO) donors to mitogen-activated human immunodeficiency virus type 1 (HIV-1)-infected peripheral blood mononuclear cultures produced a significant increase in virus replication, and this effect was not associated with a change in cell proliferation. This effect was only observed with T-tropic X4 or X4R5 virus but not with R5 virus. Moreover, HIV-1 replication in mitogen-stimulated cultures was partially prevented by the specific inhibitors of the inducible nitric oxide synthase (iNOS). NO donors also enhanced HIV-1 infection of the human T-cell lines, Jurkat and MT-2. We have also observed that NO leads to an enhancement of HIV-1 replication in resting human T cells transfected with a plasmid carrying the entire HIV-1 genome and activated with phorbol ester plus ionomycin. Thus, in those cultures NO donors strongly potentiated HIV-1 replication in a dose-dependent manner, up to levels comparable to those with tumor necrosis factor alpha (TNF-alpha) stimulation. Furthermore, iNOS inhibitors decreased HIV-1 replication in HIV-1-transfected T cells to levels similar to those obtained with neutralizing anti-TNF-alpha antibodies. Moreover, HIV-1 replication induced iNOS and TNF-alpha transcription in T cells and T-cell lines. Interestingly, NO donors also stimulated long terminal repeat (LTR)-driven transcription whereas iNOS inhibitors partially blocked TNF-alpha-induced LTR transcription. Therefore, our results suggest that NO is involved in HIV-1 replication, especially that induced by TNF-alpha.

Impaired interleukin-5 (IL-5) production by T cells as a prognostic marker of disease progression in human immunodeficiency virus type 1 (HIV-1)-infected children

We studied cytokine production by stimulated peripheral blood mononuclear cells from 55 HIV-infected children born to HIV-infected mothers, and compared it to that of exposed, but uninfected, age-matched children. Cytokine production was quantified using a commercially available specific ELISA kit. Cell proliferation was evaluated by incorporation of ((3)H) thymidine. A significant defect in type 1 cytokine production of IFN-gamma and IL-2 in HIV-infected children compared to controls was observed, but without a concomitant increase in type 2 cytokines. Indeed, IL-5 production was even lower in HIV-infected children than in controls, the IL-5 decrease being the best predictive marker of immunodeficiency. Furthermore, IL-5 levels were decreased from the early phases of HIV infection, being significantly lower in the clinical category B with respect to controls, and in AIDS with respect to both controls and children in category A. Such a strong correlation with the stage of infection has not been previously described in HIV-infected children. In addition, we found a correlation between SI/X4 viral phenotype and lower IL-5 levels. Our data suggest a dysfunctional cytokine production by PBMC from HIV-infected children as regards both Th1 and Th2 cytokines resulting from quantitative as well as qualitative defects induced by HIV-1.

Antiretroviral treatment induces a shift to type-2 cytokine responses in HIV-1 infected pregnant women

We report on a cross-sectional study on proliferation and cytokine production (IFN-gamma, IL-12, IL-5 and TNF-alpha) by peripheral blood mononuclear cells (PBMC), activated or not with phytohemagglutinin (PHA) in HIV-1-infected pregnant women, untreated or treated with zidovudine. We compared the results with healthy women, either pregnant or not, and with HIV-1-infected, non-pregnant women. The most significant results indicate that basal IL-5 production in HIV-1-infected pregnant women was higher than in the rest of the groups, being even higher in the zidovudine-treated than in the untreated group. IL-5 and TNF-alpha production by PHA-activated PBMC was also higher in HIV-1 pregnant women than in controls and infected non-pregnant women. IFN-gamma production was much higher in healthy women than in the other groups. Finally, the IFN-gamma/IL-5 (Th1-type/Th2-type-cytokine) ratio was lower in HIV-infected than in uninfected groups. Zidovudine treatment reduced basal IL-12 and increased PHA-stimulated IL-5 production. Our results indicate that both HIV-1 infection and pregnancy favored a Th2-type response by T cells. Interestingly, zidovudine-treated pregnant women had a significantly higher Th2-type response than untreated ones.

[Prognostic markers of progression to AIDS in infants vertically infected by human immunodeficiency virus type-1]

BACKGROUND

To study the prognostic AIDS progression value of the percentage of CD4+, CD8+, and plasma viral load (VL) (copies/ml) in HIV-1-vertically infected children.

PATIENTS AND METHOD

We study a cohort of 115 HIV-1 infected children older than 12 months of age. The VL was quantified using standard molecular assay. CD4 and CD8 T lymphocytes were determined by flow cytometry.

RESULTS

The children with a median of VL > 4.5 log10 (p < 0.001) and percentage of CD8+ < 25% (p = 0.05) during follow-up, progressed faster to AIDS than children with a median of VL < 4.5 log10 and CD8 > 25%. The relative risk (RR) of AIDS progression was 7-fold higher in children with median VL above 4.5 log10. When considering VL as a continuous variable, risk of progression to AIDS is 3.5-fold higher for each increase of one log10 of VL. The percentage of CD8+ T-cells had a RR of AIDS progression of 0.95/% CD8+ at entry to the study and of 0. 19/% CD8+ during follow-up, indicating protection against progression to AIDS.

CONCLUSIONS

Our results indicate that each basal values at entry in the study and during the follow-up of the percentage of CD8+ and VL helps to determine the risk of AIDS progression in HIV-1-infected children. More interestingly, the use of the two predictive markers together had higher predictive value.

[Correlation between high plasma viral load and levels of TNF-alpha and cICAM-1 in HIV-1 infected children]

AIM

To assess the relationship among plasma TNF-a and cICAM-1 levels and plasma viral load (VL) in HIV-infected children and to compare these values with those of healthy non-HIV infected children.

PATIENTS AND METHODS

We studied 44 HIV-infected children and 38 non-HIV-infected children. The VL was quantified using standard molecular assay. CD4 and CD8 lymphocyte subpopulations were determined by flow cytometry. TNF-a and cICAM-1 were quantified using commercially available specific enzyme-linked immunosorbent assay (ELISA).

RESULTS

Levels of TNF-a and cICAM-1 were higher in HIV-infected children than in non-HIV infected children. HIV-infected children with VL > 50000 copies/ml had higher levels of TNF-a (12.83; 95% CI: 24.71 to 0.95 pg/ml) and cICAM-1 (248.94; 95% CI: 419.01 to 78.84 ng/ml) than HIV-infected children with VL < 50000 copies/ml. Interestingly, we found an increase of 6.57 pg/ml of TNF-a and 119.97 ng/ml of cICAM-1 levels for each log10 of VL.

CONCLUSIONS

HIV-infected children had higher levels of TNF-a and cICAM-1 than healthy controls. Our data indicate a positive correlation among plasma TNF-a and cICAM-1 and VL levels.

[Role of cytokines and chemokines in the non-progression of HIV infection in vertically infected children]

BACKGROUND

To study the cytokine production in vertically HIV-1-infected children with more of 7 years of HIV infection and different pattern of progression.

PATIENTS AND METHODS

We study 32 HIV-1-infected children: 8 NA children (age > 7 years, asymptomatic or with light symptoms, without antiretroviral treatment and TCD4+ > 25%); 10 NE1 children (> 6 years, symptomatic, with antiretroviral treatment and TCD4+ > 25%); 14 NE2-3 children (> 6 years, symptomatic, with antiretroviral treatment and TCD4+ < 25%) and 16 (C) controls, children non-VIH+. The peripheral mononuclear cells of HIV-infected children (PBLs) were cultivated and cytokine production was quantified in the supernatant.

RESULTS

The non-stimulated PBMC from HIV-infected children produced more TNF-alpha and less IL-2 that C-group. The production of IFN-gamma was lower in the groups NE1 and NE2-3 than in C-group. The production of IFN-gamma was higher in group NA than in NE2-3. In the phytohaemagglutinin (PHA) stimulated PBLs, the production of TNF-alpha was higher in NA and NE1 than in controls. The production of IL-2 was similar in NA and NE1 than in controls. The production of IL-2 was similar in NA and NE1 than in control group, but the groups NE2-3 produced less IL-2 than control and NE1 groups. The production of IFN-gamma and RANTES were significantly higher in NA than in controls. The groups NE1 and NE2-3 produced lower levels of IL-5 than control and NA groups. The groups NE2-3 produced lower levels of IL-10 than control group. The ratio IFN-gamma/IL-5 and IFN-gamma/IL-10 were higher in group NA than in control and NE1.

CONCLUSIONS

In non-progressors HIV-infected children the immune response is conserved and we have observed an increased Th1 response, while in progressors HIV-infected children receiving antiretroviral treatment we could observe a diminished Th2 response. Moreover, our data clearly indicate that the decrease of IL-2 is an early marker of HIV-infection.

Early myeloid cells are high producers of nitric oxide upon CD40 plus IFN-gamma stimulation through a mechanism dependent on endogenous TNF-alpha and IL-1alpha

Bone marrow contains nonadherent low-density wheat germ agglutinin-positive (Fr3-WGA(+)) cells that release large amounts of NO and show natural suppressor activity if stimulated with activated T cells. We have assessed the involvement of CD40-derived signals in NO production and their cytokine requirements. Production of NO by Fr3-WGA(+) cells in co-culture with activated T cells is inhibited by a competing CD40 soluble fusion protein. Fr3-WGA(+) cells express the inducible NO synthase (iNOS) and release NO following CD40 plus IFN-gamma activation. Production of NO through CD40 is strictly dependent on endogenous TNF-alpha and / or IL-1alpha, since it is inhibited by neutralizing these cytokines or blocking the TNF receptor (p55). Both cytokines are transcribed when Fr3-WGA(+) cells are stimulated by CD40 signaling plus IFN-gamma, although TNF-alpha remains below detection limits in stimulated Fr3-WGA(+) cell cultures. Phenotypic studies combined with data on intracellular iNOS expression and cell sorting indicate that NO-producing cells are CD40, CD31 (ER-MP12), CD11b (Mac-1)low, ER-MP20 (Ly-6C) and Gr-1 (Ly-6G) positive, consistent with myeloid progenitors. The results point to early myeloid cells as an important cell source of NO once triggered by activated T cells through CD40 and IFN-gamma-derived signals, in a mechanism involving the production of TNF-alpha and / or IL-1alpha.