Giusi M. Bellistrì

Microbial translocation is associated with sustained failure in CD4+ T-cell reconstitution in HIV-infected patients on long-term highly active antiretroviral therapy.

Patients with inefficient CD4+ T-cell recovery on virogically suppressive highly active antiretroviral therapy constitute a major clinical hurdle given the threat of HIV/AIDS disease progression. We show heightened circulating lipopolysaccharide associated with plasma enterobacterial DNA and highly activated Ki67+CD4+CD8+ in 24 immunologic-nonresponders (CD4+ T-cell ≤ 200; HIV-RNA ≤ 50) compared with 11 full responders (CD4+ T-cell ≥ 400; HIV-RNA ≤ 50). These data provide novel insight into INRs pathogenesis, since they correlate augmented systemic translocation of microbial bioproducts with T-cell hyperactivation.

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.

Association between peripheral T-Lymphocyte activation and impaired bone mineral density in HIV-infected patients

BackgroundHIV-infected patients display an increased and early incidence of osteopenia/osteoporosis. We investigated whether bone metabolism disorders in HIV-infected patients are related to immune hyperactivation and premature immune senescence.MethodsBone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA): low BMD (LBMD) was defined as T-score or z-score < -1. CD4+/CD8+ phenotype (CD38/HLA-DR, CD127, CD28/CD57), and circulating IL-7, TNF-α, RANKL, OPG were measured. The variables with p < .05 were evaluated by multivariate logistic regression.Results78 patients were enrolled: 55 were LBMD. LBMD patients showed increased activated HDLADR + CD4+ and CD8+ (p = .03 and p = .002, respectively). Interestingly, no differences in senescent CD28-CD57 + CD4+/CD8+ T-cells were observed between groups. However, LBMD patients displayed a decreased CD4 + CD28- phenotype (p = .04) at the advantage of the CD28+ pool (p = .03), possibly reflecting heightened apoptosis of highly differentiated CD28-negative cells.Activated HLADR + CD4+/CD8+ and CD28 + CD4+ cells were independently associated with impaired BMD (AOR = 1.08 for each additional HLADR + CD4+ percentage higher; CI 95%,1.01-1.15; p = .02; AOR = 1.07 for each additional HLADR + CD8+ percentage higher; CI 95%,1.01-1.11; p = .01; AOR = 1.06 for each additional CD28 + CD4+ percentage higher; CI 95%,1.0-1.13; p = .05).ConclusionsHeightened T-cell activation in HIV-infected patients independently predicts BMD disorders, suggesting a critical role of immune activation in the pathogenesis of osteopenia/osteoporosis, even in patients achieving full viral suppression with HAART.

Circulating sCD14 Is Associated with Virological Response to Pegylated-Interferon-Alpha/Ribavirin Treatment in HIV/HCV Co-Infected Patients

Objectives Microbial translocation (MT) through the gut accounts for immune activation and CD4+ loss in HIV and may influence HCV disease progression in HIV/HCV co-infection. We asked whether increased MT and immune activation may hamper anti-HCV response in HIV/HCV patients. Methods 98 HIV/HCV patients who received pegylated-alpha-interferon (peg-INF-alpha)/ribavirin were retrospectively analyzed. Baseline MT (lipopolysaccharide, LPS), host response to MT (sCD14), CD38+HLA-DR+CD4+/CD8+, HCV genotype, severity of liver disease were assessed according to Early Virological Response (EVR: HCV-RNA <50 IU/mL at week 12 of therapy or ≥2 log10 reduction from baseline after 12 weeks of therapy) and Sustained Virological Response (SVR: HCV-RNA <50 IU/mL 24 weeks after end of therapy). Mann-Whitney/Chi-square test and Pearsons correlation were used. Multivariable regression was performed to determine factors associated with EVR/SVR. Results 71 patients displayed EVR; 41 SVR. Patients with HCV genotypes 1–4 and cirrhosis presented a trend to higher sCD14, compared to patients with genotypes 2–3 (p = 0.053) and no cirrhosis (p = 0.052). EVR and SVR patients showed lower levels of circulating sCD14 (p = 0.0001, p = 0.026, respectively), but similar T-cell activation compared to Non-EVR (Null Responders, NR) and Non-SVR (N-SVR) subjects. sCD14 resulted the main predictive factor of EVR (0.145 for each sCD14 unit more, 95%CI 0.031–0.688, p = 0.015). SVR was associated only with HCV genotypes 2–3 (AOR 0.022 for genotypes 1–4 vs 2–3, 95%CI 0.001–0.469, p = 0.014). Conclusions In HIV/HCV patients sCD14 correlates with the severity of liver disease and predicts early response to peg-INF-alpha/ribavirin, suggesting MT-driven immune activation as pathway of HIV/HCV co-infection and response to therapy.

Reduced CD127 expression on peripheral CD4+ T cells impairs immunological recovery in course of suppressive highly active antiretroviral therapy.

Inefficient immune recovery under highly active antiretroviral therapy (HAART) represents a clinical issue. Twenty-seven of 121 HIV+ naïve patients became immunological nonresponders (INRs) and 55 introduced therapy late [very late treated (VLT)]. INR displayed older age, lower CD4+ cell counts, down-regulation of CD127+CD4+ and higher apoptotic CD95+CD8+. VLT also showed higher activated CD38+CD8+%. The only factor associated with INR status was CD127+CD4+%. INR showed lower baseline interleukin (IL)-7 levels and a reduced expression of IL-7R (CD127) on naïve and memory T-cells, reaching significance in memory CD127+CD45R0+CD4+. These results suggest a possible role for the IL-7/IL-7R system in the pathogenesis of poor immunological recovery during HAART.

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.

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.

HIV-infected long-term nonprogressors display a unique correlative pattern between the interleukin-7/interleukin-7 receptor circuit and T-cell homeostasis.

We hypothesized that there may be a correlation between the interleukin‐7 (IL‐7)/IL‐7 receptor (IL‐7R) regulatory system and parameters of T‐cell homeostasis in HIV‐infected long‐term nonprogressors (LTNPs) as compared with patients with disease progression.

Abacavir and Cardiovascular Risk in HIV-Infected Patients: Does T Lymphocyte Hyperactivation Exert a Pathogenic Role?

Purpose of the study The association between abacavir exposure and cardiovascular disease (CVD) in HIV-infected patients is currently intensely debated. Recently, the D:A:D Study Group described increased myocardial infarction risk in patients with current/recent abacavir exposure, while repository data from GlaxoSmithKline clinical trials failed to find any association. Given the association between lymphocyte hyperactivation and CVD, and the major role of T-cell hyperactivation in HIV/AIDS, the purpose of our study was to investigate T-cell immunephenotype and proinflammatory cytokines kinetics in HIV-infected patients receiving abacavir-containing regimens.

Untangling the immunological implications of nadir on CD4+ cell recovery during suppressive highly active antiretroviral therapy.

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