Lipoprotein Profile in Immunological Non-Responders PLHIV after Antiretroviral Therapy Initiation.

Nuclear magnetic resonance (NMR)-based advanced lipoprotein tests have demonstrated that LDL and HDL particle numbers (LDL-P and HDL-P) are more powerful cardiovascular (CV) risk biomarkers than conventional cholesterol markers. Of interest, in people living with HIV (PLHIV), predictors of preclinical atherosclerosis and vascular dysfunction may be associated with impaired immune function. We previously stated that immunological non-responders (INR) were at higher CV risk than immunological responders (IR) before starting antiretroviral therapy (ART). Using Liposcale® tests, we characterized the lipoprotein profile from the same cohort of PLHIV at month 12 and month 36 after starting ART, intending to explore what happened with these indicators of CV risk during viral suppression. ART initiation dissipates the differences in lipoprotein-based CV risk markers between INR and IR, and only an increase in the number of HDL-P was found in INR + IR when compared to controls (p = 0.047). Interestingly, CD4+ T-cell counts negatively correlated with medium HDL-P concentrations at month 12 in all individuals (ρ = -0.335, p = 0.003). Longitudinal analyses showed an important increase in LDL-P and HDL-P at month 36 when compared to baseline values in both IR and INR. A proper balance between a proatherogenic and atherogenic environment may be related to the reconstitution of CD4+ T-cell count in PLHIV.

Glutaminolysis and lipoproteins are key factors in late immune recovery in successfully treated HIV-infected patients.

The immunological, biochemical and molecular mechanisms associated with poor immune recovery are far from known, and metabolomic profiling offers additional value to traditional soluble markers. Here, we present novel and relevant data that could contribute to better understanding of the molecular mechanisms preceding a discordant response and HIV progression under suppressive combined antiretroviral therapy (cART). Integrated data from nuclear magnetic resonance (NMR)-based lipoprotein profiles, mass spectrometry (MS)-based metabolomics and soluble plasma biomarkers help to build prognostic and immunological progression tools that enable the differentiation of HIV-infected subjects based on their immune recovery status after 96 weeks of suppressive cART. The metabolomic signature of ART-naïve HIV subjects with a subsequent late immune recovery is the expression of pro-inflammatory molecules and glutaminolysis, which is likely related to elevate T-cell turnover in these patients. The knowledge about how these metabolic pathways are interconnected and regulated provides new targets for future therapeutic interventions not only in HIV infection but also in other metabolic disorders such as human cancers where glutaminolysis is the alternative pathway for energy production in tumor cells to meet their requirement of rapid proliferation.

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.

Severe immune dysregulation affects CD4⁺CD25(hi)FoxP3⁺ regulatory T cells in HIV-infected patients with low-level CD4 T-cell repopulation despite suppressive highly active antiretroviral therapy.

We hypothesized that CD4(+)CD25(hi)FoxP3(+) regulatory T cells (Tregs) could be involved in the high immune activation existing in patients with low-level CD4 T-cell repopulation under suppressive high active antiretroviral therapy (hereafter, "LLR patients"). Sixteen LLR patients, 18 human immunodeficiency virus (HIV)-infected controls (hereafter, "HIV controls"), and 16 healthy subjects were included. The frequency of CD4(+)CD25(hi)FoxP3(+) and HIV-specific Treg suppressive function were assessed. Relationships between Treg and CD4/CD8 activation (HLA-DR/CD38) and the frequency of naive CD4 T-cells were assessed. Low-level patients showed a higher Treg frequency but reduced HIV-specific immunosuppressive functions than HIV controls. Whereas in healthy subjects a strong negative correlation between Tregs and activated CD8 T cells emerged (r = -0.75, P < .001), it appeared disrupted in both HIV-infected groups (r = -0.06 and P = .83 for LLR patients; r = -0.11 and P = .68 for and HIV controls). Nevertheless, in LLR patients, Tregs negatively correlated with naive CD4 T cells (r = -0.60, P = .01), whereas there was no such correlation in HIV controls (r = -0.19, P = .46) or healthy subjects (r = -0.10, P = .73). Remarkably, a higher ratio of Tregs to naive CD4 T cells was observed in LLR patients than in HIV controls (P = .001) and healthy subjects (P < .001). We conclude that LLR patients have important alterations in immunoregulation involving CD4(+)CD25(hi)FoxP3(+) Tregs. In this scenario, the role of Tregs seems to be more related to the control of the naive CD4 T-cell homeostatic proliferation, rather than to the immune activation.

Factors associated with the humoral response after three doses of COVID-19 vaccination in kidney transplant recipients.

Introduction: Kidney transplant recipients showed a weak humoral response to the mRNA COVID-19 vaccine despite receiving three cumulative doses of the vaccine. New approaches are still needed to raise protective immunity conferred by the vaccine administration within this group of high-risk patients. Methods: To analyze the humoral response and identify any predictive factors within these patients, we designed a prospective monocentric longitudinal study of Kidney transplant recipients (KTR) who received three doses of mRNA-1273 COVID-19 vaccine. Specific antibody levels were measured by chemiluminescence. Parameters related to clinical status such as kidney function, immunosuppressive therapy, inflammatory status and thymic function were analyzed as potential predictors of the humoral response. Results: Seventy-four KTR and sixteen healthy controls were included. One month after the administration of the third dose of the COVID-19 vaccine, 64.8% of KTR showed a positive humoral response. As predictive factors of seroconversion and specific antibody titer, we found that immunosuppressive therapy, worse kidney function, higher inflammatory status and age were related to a lower response in KTR while immune cell counts, thymosin-a1 plasma concentration and thymic output were related to a higher humoral response. Furthermore, baseline thymosin-a1 concentration was independently associated with the seroconversion after three vaccine doses. Discussion: In addition to the immunosuppression therapy, condition of kidney function and age before vaccination, specific immune factors could also be relevant in light of optimization of the COVID-19 vaccination protocol in KTR. Therefore, thymosin-a1, an immunomodulatory hormone, deserves further research as a potential adjuvant for the next vaccine boosters.

Differential alterations of the CD4 and CD8 T cell subsets in HIV-infected patients on highly active antiretroviral therapy with low CD4 T cell restoration.

OBJECTIVES: This study examined the homeostatic parameters possibly related to HIV-infected patients who, despite being under suppressive highly active antiretroviral therapy (HAART), show low-level CD4 T cell repopulation (LLR). METHODS: Twenty-one LLR individuals, 20 HIV-infected controls with satisfactory CD4 T cell repopulation (R) and 14 healthy subjects were studied. Markers related to activation, senescence and proliferation were analysed for both the CD4 and CD8 T cell subsets. Additionally, soluble CD14 (sCD14) and high-sensitivity C-reactive protein (hsCRP) were measured, and the CD34+ cells and the levels of interleukin-7 (IL-7) receptor were quantified. RESULTS: The frequency of naive CD4 T cells from LLR patients was significantly reduced, and these cells showed increased expression of markers for activation, senescence and proliferation as compared with naive CD4 T cells from R patients. Naive CD8 T cells were also reduced when compared with those from R patients, but did not exhibit an altered phenotype. Moreover, frequencies of effector memory T cells were higher in LLR than R patients. No differences between LLR and R patients were observed for sCD14 levels, CD34+ cells and the IL-7 receptor, although LLR patients showed a tendency toward increased levels of hsCRP >2 µg/mL. CONCLUSIONS: Patients with low CD4 T cell restoration under suppressive HAART show significant alterations in T cell homeostasis that do not appear to be related to a reduction in haematopoietic progenitors. sCD14 levels were not specifically altered in these patients. Our results agree with our previously proposed model of premature immunosenescence in LLR patients and further describe homeostatic features associated with poor CD4 recovery.

Dysregulation of iron metabolism modulators in virologically suppressed HIV-infected patients.

Background: Iron metabolism plays an essential role in cellular functions. Since virologically suppressed chronic HIV-infected subjects under effective antiretroviral treatment (ART) exhibit a persistent immune dysfunction that leads to comorbidities, iron homeostasis may be relevant in this context. We aimed to explore iron metabolism in virologically suppressed chronic HIV infected subjects under a successful ART. Methods: In this retrospective study, traditional iron metabolism biomarkers (total iron, ferritin, transferrin, and transferrin saturation index), as well as soluble transferrin receptor (sTfR), hepcidin, and inflammatory markers were determined in virologically suppressed chronic HIV-infected subjects under at least 2 years of ART (HIV) who also had >350 CD4-T-cells/mm3 (N=92) from Spain. As controls, we collected non-HIV age-matched healthy donors (Young, N=25) and elderly subjects (>65 years old; Elderly; N=25). Additionally, an external group of non-HIV patients with ferritin<50 ng/mL diagnosed with absolute iron deficiency (Ferropenic group; N=84) was included. Comparisons between groups were performed using Kruskal-Wallis or Mann-Whitney U-tests, while associations between variables were explored by Spearman's rho correlation coefficient. Results: We selected samples from HIV-infected subjects (aged 42[34-47], 95% males), young age-matched (aged 40[30-58], 60% males), and elderly controls (aged 82[78-88], 100% males). Compared to both healthy (Young and Elderly) groups, HIV exhibited decreased iron, transferrin saturation, and sTfR, and increased ferritin, but similar hepcidin levels. Notably, associations between sTfR and iron (Young, r=-0.587, p=0.002; Elderly, r=-0.496, p=0.012) or transferrin saturation index (Young, r=-0.581, p=0.002; Elderly, r=-0.489, p=0.013) were negative in both controls while positive in HIV (r=0.464, p<0.0001 and r=0.421, p<0.0001, respectively). Moreover, the expected negative correlation between hepcidin and sTfR, observed in controls (Young, r=-0.533, p=0.006; Elderly, r=-0.473, p=0.017), was absent in HIV (r=0.082; p=0.438). Interestingly, the HIV inflammatory profile differed from the Elderly one, who despite their inflammaging-related profile, succeed in maintaining these associations. Furthermore, subjects from the ferropenic group (aged 42[32-51], 5% males), showing significantly lower levels of hepcidin and higher sTfR, as expected, reflected similar correlations as those Young and Elderly, in contrast to HIV. Conclusions: Virologically suppressed chronic HIV-infected patients under successful ART exhibit altered levels of iron metabolism modulators suggesting a complex functional iron deficiency.

CD4(+)CD25(+/hi)CD127(lo) phenotype does not accurately identify regulatory T cells in all populations of HIV-infected persons.

The most commonly used regulatory T cell (Treg) phenotypes, CD4(+)CD25(hi)CD127(lo) and CD4(+)CD25(hi)FoxP3(+), were simultaneously used to determine the Treg frequency in 2 different groups of human immunodeficiency virus (HIV)-infected persons, one viremic and other aviremic. As expected, a strong correlation between both Treg phenotypes was observed in the aviremic group (r = 0.913; P < .001), but surprisingly, this correlation was completely absent in the viremic group (r = 0.143; P = .572). Data on T cell activation levels of both HIV groups suggest that the CD4(+)CD25(hi)CD127(lo) phenotype could just be mirroring the elevated numbers of activated non-regulatory T cells in the viremic HIV group.

Immunological features beyond CD4/CD8 ratio values in older individuals.

The CD4/CD8 T-cell ratio is emerging as a relevant marker of evolution for many pathologies and therapies. We aimed to explore immunological features beyond CD4/CD8 ratio values in older subjects (>65 years old) who were classified as having lower (<1.4), intermediate (1.4-2), or higher (>2) ratio values. The lower group showed a lower thymic output (sj/ß-TREC ratio) and frequency of naïve T-cells, concomitant with increased mature T-cells. In these subjects, the CD4 T-cell subset was enriched in CD95+ but depleted of CD98+ cells. The regulatory T-cell (Treg) compartment was enriched in CTLA-4+ cells. The CD8 T-cell pool exhibited increased frequencies of CD95+ cells but decreased frequencies of integrin-ß7+ cells. Interestingly, in the intermediate group, the CD4 pool showed greater differences than the CD8 pool, mostly for cellular senescence. Regarding inflammation, only hsCRP was elevated in the lower group; however, negative correlations between the CD4/CD8 ratio and ß2-microglobulin and sCD163 were detected. These subjects displayed trends of more comorbidities and less independence in daily activities. Altogether, our data reveal different thymic output and immune profiles for T-cells across CD4/CD8 ratio values that can define immune capabilities, affecting health status in older individuals. Thus, the CD4/CD8 ratio may be used as an integrative marker of biological age.

Increased Frequencies of Myeloid-Derived Suppressor Cells Precede Immunodiscordance in HIV-Infected Subjects.

Background: We have previously observed increased levels of inflammatory biomarkers and Th17 as well as Treg cells, but not other T-cell specific alterations, preceding immunodiscordance of successfully-treated HIV-infected subjects. Our hypothesis is that this could be related with potential alterations in myeloid-derived suppressor cells (MDSCs) and/or monocyte subsets. Methods: We determined the frequencies of MDSCs and monocyte subsets and the expression of several functional markers (CCR2, ß7-integrin, IDO, PDL1, CD11b) in HIV-infected subjects before treatment. We additionally analyzed follow-up samples after 24 months of suppressive cART in a subgroup of subjects. Bivariate regressions were performed, and correlations with soluble proinflammatory and bacterial translocation biomarkers, as well as with Th17/Treg ratio and anti-CMV titers were explored. Results: Increased frequencies of MDSCs, but normal distribution of monocyte subsets, preceded immunodiscordance. The expression of several functional markers, such as CCR2, CD16, CD11b and PDL1, on MDSCs and monocyte subsets was altered in this scenario. MDSC and monocyte-related functional markers were associated with soluble biomarkers and T-cell parameters. Several of these cellular alterations were not restored after 24 months of suppressive cART. Conclusion: An early immunosuppressive environment, characterized by the expansion of MDSCs and Tregs, precedes immunodiscordance and is related with a highly inflammatory status.

High circulating SDF-1and MCP-1 levels and genetic variations in CXCL12, CCL2 and CCR5: Prognostic signature of immune recovery status in treated HIV-positive patients.

BACKGROUND: The underlying mechanisms of incomplete immune reconstitution in treated HIV-positive patients are very complex and may be multifactorial, but perturbation of chemokine secretion could play a key role in CD4+T-cell turnover. METHODS: We evaluated the circulating baseline and 48-week follow-up concentrations of SDF-1/CXCL12, fractalkine/CX3CL1, MCP-1/CCL2, MIP-α/CCL3, MIP-ß/CCL4 and RANTES/CCL5, and we estimated their association with CXCL12, CX3CR1, CCR2, CCL5 and CCR5 single nucleotide polymorphisms (SNPs) to investigate multiple chemokine-chemokine receptor signatures associated with immune dysregulation preceding poor immune recovery. FINDINGS: The circulating concentrations and gene expression patterns of SDF-1/CXCL12 (CXCL12 rs1801157) and MCP-1/CCL2 (CCR2 rs1799864_814) were associated with immune recovery status. CCR2 rs1799864_814 and CCR5 rs333_814 (Δ32) determine the baseline plasma RANTES and MIP-α concentrations, respectively, in participants with poor immune response. INTERPRETATION: SDF-1/CXCL12 and MCP-1/CCL2 could be considered prognostic markers of immune failure despite suppressive antiretroviral therapy. The strong linkage disequilibrium (LD) between CCR2 rs1799864_814 and CCR5 rs1800024 indicated that the alleles of each gene are inherited together more often than would be expected by chance. FUNDING: This work was supported by Fondo de Investigacion Sanitaria and SPANISH AIDS Research Network (ISCIII-FEDER); AGAUR and Gilead Fellowship. FV and YMP are supported by grants from the Programa de Intensificación (ISCIII) and Servicio Andaluz de Salud, respectively. JVG,EY and LR are supported by the Instituto de Salud Carlos III (ISCIII). AR is supported by Departament de Salut, Generalitat de Catalunya and by the Instituto de Salud Carlos III (ISCIII).

IL-7/IL-7R gene variants impact circulating IL-7/IL-7R homeostasis and ART-associated immune recovery status.

A relationship between polymorphisms in genes encoding interleukin 7 (IL-7) and its cellular receptor (IL-7R) and antiretroviral therapy (ART)-associated immune recovery in HIV subjects has been previously reported. However, details of this relationship remain unclear, and the association of these polymorphisms with circulating IL-7/IL-7R levels is scarce. Here, we explored whether IL-7/IL-7R axis was associated with quantitative CD4+ T-cell recovery in HIV-infected subjects. IL-7/IL-7R polymorphisms were assessed by genotyping, and multiple inheritance models were used to estimate both, their association with low pre-ART CD4+ T-cell counts and incomplete immune recovery status after 48 weeks of suppressive ART. Integrated data from genetic variants association and soluble plasma IL-7/IL-7R quantification suggest that IL-7/IL-7R genotype expression could alter the homeostatic balance between soluble and membrane-bound receptors. The haplotype analyses indicates that allele combinations impacts pre-ART circulating CD4+ T-cell counts, immune recovery status and the absolute increment of CD4+ T-cell counts. The knowledge about how IL-7/IL-7R axis is related to quantitative CD4+ T-cell recovery and immune recovery status after initiating ART could be useful regarding T-cell reservoirs investigations in HIV subjects.

Increased frequencies of Th17 cells and IL17a-producing regulatory T-cells preceding the immunodiscordant response to antiretroviral treatment.

BACKGROUND: Despite the fact that antiretroviral therapy (cART) suppresses HIV-viremia, an adequate CD4 T-cell recovery is not always achieved (immunodiscordant response to cART). IL17a-producing CD4 T-cells (Th17) constitutes an important subset involved in the preservation of mucosal surfaces integrity, which depletion has been associated with disease progression in HIV-infection. However, whether Th17 frequency at cART initiation is associated with a poor CD4 T-cell recovery has not been yet explored. Our aim was to explore whether the Th17 cells and other IL17a-producing T-cell subsets at cART initiation were associated with a subsequent immunodiscordant response to cART. METHODS: We selected pre-cART samples of antiretroviral-naïve subjects with and without a low CD4 recovery after cART (LR-subjects and HR-subjects, respectively). Peripheral blood mononuclear cells (PBMCs) were stimulated with PMA/ionomycine, and the production of several cytokines including IL17a was analyzed by flow cytometry. RESULTS: A trend to higher Th17 (p = 0.05) and increased frequencies of IL17a-producing Treg (p = 0.011) was found in LR-subjects before cART onset. Despite increased frequencies of both Treg and Th17 in LR-subject at cART initiation, no alteration of Treg/Th17 ratio was observed. While polifunctional profile of CD4 T-cells was not different, frequencies of CD4 T-cells producing cytokine-combinations including IL17a were increased in LR-subjects. CONCLUSION: Increased frequencies of Th17, IL17a-producing Treg and CD4 T-cells producing specific IL17a-containing combinations of cytokines, precede the immunodiscordant response to cART, suggesting a potential contribution of these subsets in such anomalous response to cART.

Circulating metabolomic profile can predict dyslipidemia in HIV patients undergoing antiretroviral therapy.

BACKGROUND AND AIMS: Dyslipidemia in HIV-infected patients is unique and pathophysiologically associated with host factors, HIV itself and the use of antiretroviral therapy (ART). The use of nuclear magnetic resonance spectroscopy (NMR) provides additional data to conventional lipid measurements concerning the number of lipoprotein subclasses and particle sizes. METHODS: To investigate the ability of lipoprotein profile, we used a circulating metabolomic approach in a cohort of 103 ART-naive HIV-infected patients, who were initiating non-nucleoside analogue transcriptase inhibitor (NNRTI)-based ART, and we subsequently followed up these patients for 36 months. Univariate and multivariate analyses were performed to evaluate the predictive power of NMR spectroscopy. RESULTS: VLDL-metabolism (including VLDL lipid concentrations, sizes, and particle numbers), total triglycerides and lactate levels resulted in good classifiers of dyslipidemia (AUC 0.903). Total particles/HDL-P ratio was significantly higher in ART-associated dyslipidemia compared to ART-normolipidemia (p = 0.001). Large VLDL-Ps were positively associated with both LDL-triglycerides (ρ 0.682, p < 0.001) and lactate concentrations (ρ 0.416, p < 0.001), the last one a marker of mitochondrial low oxidative capacity. CONCLUSIONS: Our data suggest that circulating metabolites have better predictive values for HIV/ART-related dyslipidemia onset than do the biochemical markers associated with conventional lipid measurements. NMR identifies changes in VLDL-P, lactate and LDL-TG as potential clinical markers of baseline HIV-dyslipidemia predisposition. Differences in circulating metabolomics, especially differences in particle size, are indicators of important derangements of mitochondrial function that are linked to ART-related dyslipidemia.

Monocyte Phenotype and Polyfunctionality Are Associated With Elevated Soluble Inflammatory Markers, Cytomegalovirus Infection, and Functional and Cognitive Decline in Elderly Adults.

Monocytes are mediators of the inflammatory response and include three subsets: classical, intermediate, and nonclassical. Little is known about the phenotypical and functional age-related changes in monocytes and their association with soluble inflammatory biomarkers, cytomegalovirus infection, and functional and mental decline. We assayed the activation ex vivo and the responsiveness to TLR2 and TLR4 agonists in vitro in the three subsets and assessed the intracellular production of IL1-alpha (α), IL1-beta (ß), IL-6, IL-8, TNF-α, and IL-10 of elderly adults (median 83 [67-90] years old;n= 20) compared with young controls (median 35 [27-40] years old;n= 20). Ex vivo, the elderly adults showed a higher percentage of classical monocytes that expressed intracellular IL1-α (p= .001), IL1-ß (p= .001), IL-6 (p= .002), and IL-8 (p= .007). Similar results were obtained both for the intermediate and nonclassical subsets and in vitro. Polyfunctionality was higher in the elderly adults. The functionality ex vivo was strongly associated with soluble inflammatory markers. The activation phenotype was independently associated with the anti-cytomegalovirus IgG levels and with functional and cognitive decline. These data demonstrate that monocytes are key cell candidates for the source of the high soluble inflammatory levels. Our findings suggest that cytomegalovirus infection might be a driving force in the activation of monocytes and is associated with the functional and cognitive decline.

Detectable viral load aggravates immunosenescence features of CD8 T-cell subsets in vertically HIV-infected children.

BACKGROUND: CD8 T cells are crucial in the immune responses against HIV infection, but HIV-infected adults suffer a naive CD8 T-cell depletion and accelerated senescence caused by chronic antigen stimulation. Although HIV-infected children preserve a better immune reconstitution capacity their CD8 responses are defective. We wanted to know, whether HIV vertical transmission produces a premature aging of the CD8 population due to antigen exposition to HIV from birth and persistent chronic activation. METHODS: We conducted a multicentre cross-sectional study that compared vertically HIV-infected children with detectable (viremic) or undetectable (aviremic) viral load and age-matched healthy children. Using multiparameter flow cytometry, we studied within the CD8 population the frequencies of naive, memory, effector memory (effector memory), and TemRA subsets and measured markers of senescence, activation, and proliferation in these cells. RESULTS: We found that naive subset in viremic children was markedly decreased and had a replicative senescence phenotype. Furthermore, viremic children showed increased frequencies of memory, TEM and TemRA CD8 T cells, with a more activated and replicative senescence phenotype. We found that HIV-infected children with undetectable viral load have an increased senescence in memory and effector CD8 T cells, but the frequencies and phenotype of the CD8 subsets analyzed are comparable to healthy children. CONCLUSIONS: [corrected] Our study shows that CD8 T cells of HIV-infected children have a more senescent phenotype when compared with age-matched healthy children. Interestingly enough, our results support the importance of maintaining undetectable viral load in HIV-infected children to avoid the premature ageing and dysfunction of CD8 T cells.