Esther Merlini

Microbial translocation predicts disease progression of HIV-infected antiretroviral-naive patients with high CD4 + cell count

Objectives:We investigated the significance of microbial translocation measured on average 3 years after HIV seroconversion in driving disease progression in HIV+ untreated patients with high CD4+ cell count. Design:We included ICONA patients with documented last HIV-negative and first HIV-positive test, at least one plasma sample stored while antiretroviral therapy (ART)-naive and CD4+ cell count greater than 200 cells/&mgr;l. Methods:Microbial translocation [lipopolysaccharide (LPS), sCD14 and EndoCAb] and immune activation (IL-6 and TNF-&agr;) were measured. Correlation between immune activation, microbial translocation, CD4+ and plasma HIV-RNA was evaluated by linear regression and nonparametric Spearmans rho. The independent predictive value of these markers on time to progression to the combined endpoint of AIDS, death, CD4+ cell count less than 200 cells/&mgr;l or start of antiretroviral therapy (ART) was assessed using survival analysis. Results:We analysed 1488 biomarker measures from 379 patients. A median of 3.1 years after the estimated seroconversion date [interquartile range (IQR) 1.6–5.4], median (IQR) markers values were LPS, 110 pg/ml (IQR 75–215), sCD14, 3.3 &mgr;g/ml (2.2–4.8), IL-6, 1.1 pg/ml (0.6–1.9) and TNF-&agr;, 2.4 pg/ml (1.8–3.4). Two hundred and sixty progression events were recorded over a median of 1.6 years from the first sample (2% AIDS, 84% ART initiation, 12% CD4+ cell count less than 200 cells/&mgr;l and 2% death). LPS was the only biomarker associated with this primary composite outcome independently of age, HIV-RNA and CD4+ (relative hazard = 1.40 per loge higher, 95% confidence interval 1.18–1.66, P < 0.001). Conclusion:Circulating LPS in the first years of chronic HIV infection is a strong predictor of disease progression independent of CD4+ cell count and HIV viraemia and may be considered a candidate biomarker for HIV monitoring and evaluation in clinical trials.

T-cell phenotypes, apoptosis and inflammation in HIV+ patients on virologically effective cART with early atherosclerosis.

Objective We investigated the potential relationship between T-cell phenotype, inflammation, endotoxemia, and atherosclerosis evaluated by carotid intima-media thickness (IMT) in a cohort of HIV-positive patients undergoing long-term virologically suppressive combination antiretroviral therapy (cART). Design We studied 163 patients receiving virologically suppressive cART. Methods We measured IMT (carotid ultrasound); CD4+/CD8+ T-cell activation (CD38, CD45R0), differentiation (CD127), apoptosis (CD95), and senescence (CD28, CD57) (flow cytometry); plasma sCD14, IL-6, TNF- α, sVCAM-1, hs-CRP, anti-CMV IgG (ELISA); LPS (LAL). The results were compared by Mann-Whitney, Kruskal-Wallis or Chi-square tests, and factors associated with IMT were evaluated by multivariable logistic regression. Results Of 163 patients, 112 demonstrated normal IMT (nIMT), whereas 51 (31.3%) had pathological IMT (pIMT: ≥1 mm). Of the patients with pIMT, 22 demonstrated an increased IMT (iIMT), and 29 were shown to have plaques. These patient groups had comparable nadir and current CD4+, VLs and total length of time on cART. Despite similar proportions of CD38-expressing CD8+ cells (p = .95), pIMT patients exhibited higher activated memory CD8+CD38+CD45R0+ cells (p = .038) and apoptotic CD4+CD95+ (p = .01) and CD8+CD95+ cells (p = .003). In comparison to nIMT patients, iIMT patients tended to have lower numbers of early differentiated CD28+CD57− memory CD4+ (p = .048) and CD28–CD57−CD8+ cells (p = .006), both of which are associated with a higher proliferative potential. Despite no differences in plasma LPS levels, pIMT patients showed significantly higher circulating levels of sCD14 than did nIMT patients (p = .046). No differences in anti-CMV IgG was shown. Although circulating levels of sCD14 seemed to be associated with a risk of ATS in an unadjusted analysis, this effect was lost after adjusting for classical cardiovascular predictors. Conclusions Despite the provision of full viral suppression by cART, a hyperactivated, pro-apoptotic T-cell profile characterizes HIV-infected patients with early vascular damage, for whom the potential contribution of subclinical endotoxemia and anti-CMV immunity should be investigated further.

Maraviroc as intensification strategy in HIV-1 positive patients with deficient immunological response: an Italian randomized clinical trial.

Background Immunological non-responders (INRs) lacked CD4 increase despite HIV-viremia suppression on HAART and had an increased risk of disease progression. We assessed immune reconstitution profile upon intensification with maraviroc in INRs. Methods We designed a multi-centric, randomized, parallel, open label, phase 4 superiority trial. We enrolled 97 patients on HAART with CD4+<200/µL and/or CD4+ recovery ≤25% and HIV-RNA<50 cp/mL. Patients were randomized 1:1 to HAART+maraviroc or continued HAART. CD4+ and CD8+ CD45+RA/RO, Ki67 expression and plasma IL-7 were quantified at W0, W12 and W48. Results By W48 both groups displayed a CD4 increase without a significant inter-group difference. A statistically significant change in CD8 favored patients in arm HAART+maraviroc versus HAART at W12 (p=.009) and W48 (p=.025). The CD4>200/µL and CD4>200/µL + CD4 gain ≥25% end-points were not satisfied at W12 (p=.24 and p=.619) nor at W48 (p=.076 and p=.236). Patients continuing HAART displayed no major changes in parameters of T-cell homeostasis and activation. Maraviroc-receiving patients experienced a significant rise in circulating IL-7 by W48 (p=.01), and a trend in temporary reduction in activated HLA-DR+CD38+CD4+ by W12 (p=.06) that was not maintained at W48. Conclusions Maraviroc intensification in INRs did not have a significant advantage in reconstituting CD4 T-cell pool, but did substantially expand CD8. It resulted in a low rate of treatment discontinuations. Trial Registration ClinicalTrials.gov NCT00884858 http://clinicaltrials.gov/show/NCT00884858

Impaired gut junctional complexes feature late-treated individuals with suboptimal CD4+ T-cell recovery upon virologically suppressive combination antiretroviral therapy.

Objective:HIV-infected individuals with incomplete CD4+ T-cell recovery upon combination antiretroviral therapy (cART) display high levels of immune activation and microbial translocation. However, whether a link exists between gut damage and poor immunological reconstitution remains unknown. Design:Cross-sectional study of the gastrointestinal tract in late cART-treated HIV-infected individuals: 15 immunological nonresponders (CD4+ <350 cells/&mgr;l and/or delta CD4+ change from baseline <30%); 15 full responders (CD4+ >350 cells/&mgr;l and/or delta CD4+ change from baseline >30%). Methods:We assessed gut structure (junctional complex proteins in ileum and colon) and function (small intestine permeability/damage and microbial translocation parameters). The composition of the fecal microbiome and the size of the HIV reservoir in the gut and peripheral blood were investigated as possible mechanisms underlying mucosal impairment. Results:Markers of intestinal permeability, damage, systemic inflammation, and microbial translocation were comparable in all study individuals, yet the expression of junctional complex proteins in gut biopsies was significantly lower in HIV-infected patients with incomplete CD4+ restoration and negatively correlated with markers of CD4+ reconstitution. Electron microscopy revealed dilated intercellular spaces in individuals lacking immunological response to cART, yet not in patients displaying CD4+ T-cell recovery. Analysis of the fecal microbiome revealed an overall outgrowth of Bacteroides–Prevotella spp. with no differences according to CD4+ T-cell reconstitution. Interestingly, HIV reservoirs in peripheral CD4+ T cells and intestinal tissue negatively correlated with immune recovery. Conclusion:These observations establish gut damage and the size of the HIV reservoir as features of deficient immunological response to cART and provide new elements for interventional strategies in this setting.

Role of In Vitro Stimulation with Lipopolysaccharide on T-Cell Activation in HIV-Infected Antiretroviral-Treated Patients

We investigated the effect of LPS in vitro stimulation on T-cell activation in HIV-infected patients with different CD4+ recovery on HAART. PBMCs from 30 HIV-positive, HAART-treated, aviremic individuals with different CD4+ reconstitution (Low Responders: CD4+ < 350/μL; Intermediate Responders: CD4+ 350–599/μL; High Responders: CD4+ ≥ 600/μL) were cultured with LPS and the proportion of HLA-DR/CD38- and Ki67-expressing CD4+/CD8+ T-cells was measured (flow cytometry). Upon LPS stimulation, significantly higher CD4+ and CD8+HLA-DR+ cells were shown in LR and IR versus HIV-negative controls. While no differences in the proportion of LPS-stimulated CD4+CD38+ cells were recorded amongst HIV-positive subgroups, CD8+CD38+ cells were more elevated in patients with lower CD4+ recovery on HAART (i.e., LR and IR). Upon in vitro LPS stimulation, HLA-DR and CD38 expression on T-cells are differentially regulated. While HLA-DR induction reflects impaired CD4+ reconstitution on HAART, cell-surface CD38 expression is increased only on CD8+ T-cells, allowing to speculate that the sole induction of CD38 on CD4+ cells may not be sufficient to depict LPS-driven immune activation in HIV.

Reduced Central Memory CD4+ T Cells and Increased T-Cell Activation Characterise Treatment-Naive Patients Newly Diagnosed at Late Stage of HIV Infection

Objectives. We investigated immune phenotypes of HIV+ patients who present late, considering late presenters (LPs, CD4+ < 350/μL and/or AIDS), advanced HIV disease (AHD, CD4+ < 200/μL and/or AIDS), and AIDS presenters (AIDS-defining condition at presentation, independently from CD4+). Methods. Patients newly diagnosed with HIV at our clinic between 2007–2011 were enrolled. Mann-Whitney/Chi-squared tests and logistic regression were used for statistics. Results. 275 patients were newly diagnosed with HIV between January/2007–March/2011. 130 (47%) were LPs, 79 (29%) showed AHD, and 49 (18%) were AIDS presenters. LP, AHD, and AIDS presenters were older and more frequently heterosexuals. Higher CD8+%, lower CD127+CD4+%, higher CD95+CD8+%, CD38+CD8+%, and CD45R0+CD38+CD8+% characterized LP/AHD/AIDS presentation. In multivariate analysis, older age, heterosexuality, higher CD8+%, and lower CD127+CD4+% were confirmed associated with LP/AHD. Lower CD4+ and higher CD38+CD8+% resulted independently associated with AIDS presentation. Conclusions. CD127 downregulation and immune activation characterize HIV+ patients presenting late and would be studied as additional markers of late presentation.

Increased Bone Marrow Interleukin-7 (IL-7)/IL-7R Levels but Reduced IL-7 Responsiveness in HIV-Positive Patients Lacking CD4+ Gain on Antiviral Therapy

Background The bone marrow (BM) cytokine milieu might substantially affect T-lymphocyte homeostasis in HIV-positive individuals. Interleukin-7 (IL-7) is a bone marrow-derived cytokine regulating T-cell homeostasis through a CD4+-driven feedback loop. CD4+ T-lymphopenia is associated with increased free IL-7 levels and reduced IL-7R expression/function, which are only partially reverted by highly active antiretroviral therapy (HAART). We investigated the BM production, peripheral expression and signaling (pStat5+ and Bcl-2+ CD4+/CD8+ T cells) of IL-7/IL-7Rα in 30 HAART-treated HIV-positive patients who did not experience CD4+ recovery (CD4+ ≤200/µl) and who had different levels of HIV viremia; these patients included 18 immunological nonresponders (INRs; HIV-RNA≤50), 12 complete failures (CFs; HIV-RNA>1000), and 23 HIV-seronegative subjects. Methods We studied plasma IL-7 levels, IL-7Rα+CD4+/CD8+ T-cell proportions, IL-7Rα mRNA expression in PBMCs, spontaneous IL-7 production by BM mononuclear cells (BMMCs), and IL-7 mRNA/IL-7Rα mRNA in BMMC-derived stromal cells (SCs). We also studied T-cell responsiveness to IL-7 by measuring the proportions of pStat5+ and Bcl-2+ CD4+/CD8+ T cells. Results Compared to HIV-seronegative controls, CFs and INRs presented elevated plasma IL-7 levels and lower IL-7Rα CD4+/CD8+ cell-surface expression and peripheral blood production, confirming the most relevant IL-7/IL-7R disruption. Interestingly, BM investigation revealed a trend of higher spontaneous IL-7 production in INRs (p = .09 vs. CFs) with a nonsignificant trend toward higher IL-7-Rα mRNA levels in BMMC-derived stromal cells. However, upon IL-7 stimulation, the proportion of pStat5+CD4+ T cells did not increase in INRs despite higher constitutive levels (p = .06); INRs also displayed lower Bcl-2+CD8+ T-cell proportions than controls (p = .04). Conclusions Despite severe CD4+ T-lymphopenia and a disrupted IL-7/IL-7R profile in the periphery, INRs display elevated BM IL-7/IL-7Rα expression but impaired T-cell responsiveness to IL-7, suggesting the activity of a central compensatory pathway targeted to replenish the CD4+ compartment, which is nevertheless inappropriate to compensate the dysfunctional signaling through IL-7 receptor.

Maraviroc intensification for HIV-1-positive immunological non-responders (INRs) despite virological suppression during HAART

7‐11 November 2010, Tenth International Congress on Drug Therapy in HIV Infection, Glasgow, UK

Switching to elvitegravir/cobicistat/emtricitabine/tenofovirdisoproxil fumarate single-tablet regimen (Stribild†):effects on T-cell compartment and HIV reservoirs

Scientific advances over the 35 years since AIDS was first recognized as a new disease, have put us on a clear path towards ending the HIV/AIDS pandemic. Scaling‐up access to antiretroviral therapy (ART) and HIV prevention strategies, such as pre‐exposure prophylaxis, could dramatically decrease HIV‐related deaths and the rate of new HIV infections. Current and future scientific advances, notably in HIV vaccine and cure research, will accelerate this process. Two major directions in HIV vaccine development will be discussed: building on the results from RV 144, the clinical trial in Thailand that resulted in the first modest signal of efficacy for a HIV vaccine; and structure‐based immunogen design to elicit broadly neutralizing antibodies. Cure research has accelerated greatly over the past few years in two areas. The first is the prospect of eradicating the HIV reservoir altogether (i.e. a classic cure), which might involve novel latency‐reversing and immunotoxic regimens and gene editing techniques to create a host cellular environment that does not allow HIV replication. The second approach involves controlling viral rebound following discontinuation of ART to achieve sustained virological remission employing strategies, such as passive transfer of broadly neutralizing antibodies and therapeutic vaccination. In 2016, the arsenal of scientifically proven interventions available, as well as the hope of others to come, offer unprecedented opportunities to make major gains in the fight against HIV/AIDS. With a major global commitment to implement these scientific advances, the end of the HIV/AIDS pandemic is now achievable.

Invariant natural killer T (iNKT) cells in HAART-treated, HIV-positive patients with bone and cardiovascular impairment.

Background Invariant Natural Killer T (iNKT) cells represent a determinant in the course of infections and diseases, however, their role in the pathogenesis of non-infectious co-morbidities in HIV-positive patients is unknown. Methods Flow cytometry was used to investigate iNKT cell frequency, phenotype and function in HIV-infected patients on HAART with bone and/or cardiovascular disorders and in HIV-positive controls free from co-morbidities. Results iNKT cells from subjects with bone and cardiovascular impairment expressed high levels of CD161 and predominantly secreted TNF. iNKT cells from individuals with bone disease alone did not show any distinctive phenotypical or functional characteristics. The functional capacity of iNKT cells in patients with cardiovascular disorder was impaired with no cytokine release upon stimulation. Conclusion iNKT cells may have a role in non-infectious co-morbidities in treated HIV disease, possibly through the exacerbation of inflammation. Further studies are needed to investigate iNKT cells in the pathogenesis of non-communicable disorders in HIV infection.