Marco Casciaro

Virus-specific CD8+ T cells with type 1 or type 2 cytokine profile are related to different disease activity in chronic hepatitis C virus infection

The present study demonstrates that the quality of the virus‐specific CD8+ T cell responses, as detected by both enzyme‐linked immunospot assay and specific MHC‐peptide tetramers, changed in relation to the different disease activity in chronically hepatitis C virus‐infected patients. Indeed, both the serum alanine transaminase and the hepatic flogosis levels were related directly to the frequencies of peripheral memory effector CD8+ T cells producing IFN‐γ (Tc1), but inversely to the frequencies of those producing both IL‐4 and IL‐10 (Tc2). Longitudinal studies highlighted that Tc1 or Tc2 responses fluctuate in relation to the different phases of the disease in the same individual. Furthermore, the Tc1 or Tc2 phenotype correlates with tetramer‐positive cells expressing either CXCR3 or CCR3, promoting differential tissue localization of these cells and the maintenance of T cell homeostasis. Finally, studies at the level of liver‐infiltrating lymphocytes indicated that they produced both IFN‐γ and IL‐4 with an evident bias towards the Tc1‐like phenotype. Our studies suggest that the progressive fluctuation of Tc1 and Tc2 responses may play a fundamental role in maintaining a long‐lasting low‐level liver inflammation, and may constitute the basis for new therapeutic strategies of immune regulation.

Is NOX2 Upregulation Implicated in Myocardial Injury in Patients with Pneumonia

In the present study, we tested the hypothesis that oxidative stress could be implicated in myocardial damage during the acute phase of pneumonia. NOX2 activation, the catalytic subunit of NADPH oxidase, and high-sensitivity cardiac troponin T (hs-cTnT) elevation have been analyzed in two hundred forty-eight consecutive patients hospitalized for community-acquired pneumonia. Serum NOX2-derived peptide (sNOX2-dp), a marker of NOX2 activation, and 8-isoprostaglandin F2α (8-iso-PGF2α), a marker of oxidative stress, were measured upon admission; serum hs-cTnT and ECG were measured every 12 and 24 h, respectively. One hundred thirty-five patients (54%) showed elevated serum levels of hs-cTnT (>0.014 μg/L). A logistic regression analysis showed sNOX2-dp (p<0.001), Pneumonia Severity Index score (p<0.001), renal failure (p=0.024), and ejection fraction (p<0.001) as independent predictors of elevated serum levels of hs-cTnT. Serum sNOX2-dp was linearly correlated with hs-cTnT (Rs=0.538; p<0.001) and 8-iso-PGF2α (Rs=0.354; p<0.001). The study provides the first evidence of a significant association between serum cardiac Troponin T elevation and NOX2 upregulation in patients with pneumonia. This finding raises the hypothesis that NOX2-derived oxidative stress may be implicated in myocardial injury and that its inhibition could be a novel therapeutic strategy to limit it.

Hepatitis C flare due to superinfection by genotype 4 in an HCV genotype 1b chronic carrier

We report here on a patient affected by chronic hepatitis C who developed acute hepatitis C virus (HCV) superinfection with replacement of genotype 1b by genotype 4. The history revealed no risk factors for a new exposure to HCV, with the exception of colonoscopy with mucosal biopsy performed about 3 months before. This report underlines the absence of an effective immune-mediated cross-protection against different HCV genotypes. Moreover, the possible relationship between HCV infection and colonoscopy points out the importance of strict adherence to international guidelines for disinfection and cleaning of invasive diagnostic tools for all subjects examined, including HCV chronic carriers.

Defective Th1 and Th2 cytokine synthesis in the T-T cell presentation model for lack of CD40/CD40 ligand interaction.

In this study, T or NK cell clones used as antigen‐presenting cells (T‐ or NK‐APC) were shown to be significantly less efficient than professional APC in inducing Th1 and Th2 cytokines by antigen‐specific T cell clones. This phenomenon was not related to a limited engagement of TCR by T‐APC, since comparable thresholds of TCR down‐regulation were shown when antigen was presented by either T‐APC or professional APC. Rather, the stimulatory T‐APC weakness was due to their inability, because they are CD40−, to provide the appropriate co‐stimuli to responder T cells both indirectly via IL‐12, and partially via direct CD40L triggering on T cells. Indeed, the simultaneous addition of IL‐12 and reagents directly engaging CD40L on responder T cells restored T cell cytokine synthesis when antigen was presented by T‐APC. In addition, either IL‐12 production or blocking of T cell cytokine synthesis by anti‐IL‐12 p75 antibodies was evident only when professional APC were used in our antigen‐specific system. The down‐regulation of cytokine synthesis in the system of T‐T cell presentation could represent a novel mechanism of immune regulation, which may intervene to switch off detrimental Th1‐ or Th2‐mediated responses induced by antigen presentation among activated T cells infiltrating inflamed tissues.

Incidence of bleeding in patients with atrial fibrillation and advanced liver fibrosis on treatment with vitamin K or non-vitamin K antagonist oral anticoagulants

OBJECTIVES To investigate the incidence of bleeding events in atrial fibrillation (AF) patients treated with vitamin K (VKAs) or non-vitamin K antagonist oral anticoagulants (NOACs) screened for the presence of liver fibrosis (LF). BACKGROUND Previous studies provided conflicting results on bleeding risk in AF patients with liver disease on VKAs, and no data on NOACs in this setting are available. METHODS Post-hoc analysis of a prospective, observational multicentre study including 2330 AF outpatients treated with VKAs (n = 1297) or NOACs (n = 1033). Liver damage was quantified by the FIB-4 score (>3.25), a validated marker of LF. The primary endpoint was the incidence of any bleeding, according to ISTH classification. RESULTS A high FIB-4 was present in 129 (5.5%) patients: 77 (5.9%) on VKA and 52 (5.0%) on NOACs (p = 0.344). During follow-up, 357 (15.3%) patients experienced a bleeding: 261 (80 major and 180 minor) with VKAs (7.2%/year), and 96 (40 major and 56 minor) with NOACs (6.4%/year). In VKA-treated patients, but not in those on NOACs, FIB-4 >3.25 was associated with higher major bleeding (14.3% vs. 5.6%, log-rank test p < 0.001). Multivariable Cox regression model showed that FIB-4 was associated with major bleeding only in VKA-treated patients (HR: 3.075, 95% CI 1.626-5.818, p = 0.001). On multivariable analysis, FIB-4 was not significantly associated with CVEs neither in VKA or NOAC-treated patients. CONCLUSION We found a significant association between LF and major bleedings in AF patients treated with VKA, which was not evident in patients on NOACs.

Impaired flow-mediated dilation in hospitalized patients with community-acquired pneumonia

BACKGROUND Community-acquired pneumonia (CAP) is complicated by cardiovascular events as myocardial infarction and stroke but the underlying mechanism is still unclear. We hypothesized that endothelial dysfunction may be implicated and that endotoxemia may have a role. METHODS Fifty patients with CAP and 50 controls were enrolled. At admission and at discharge, flow-mediated dilation (FMD), serum levels of endotoxins and oxidative stress, as assessed by serum levels of nitrite/nitrate (NOx) and isoprostanes, were studied. RESULTS At admission, a significant difference between patients with CAP and controls was observed for FMD (2.1±0.3 vs 4.0±0.3%, p<0.001), serum endotoxins (157.8±7.6 vs 33.1±4.8pg/ml), serum isoprostanes (341±14 vs 286±10 pM, p=0.009) and NOx (24.3±1.1 vs 29.7±2.2μM). Simple linear correlation analysis showed that serum endotoxins significantly correlated with Pneumonia Severity Index score (Rs=0.386, p=0.006). Compared to baseline, at discharge CAP patients showed a significant increase of FMD and NOx (from 2.1±0.3 to 4.6±0.4%, p<0.001 and from 24.3±1.1 to 31.1±1.5μM, p<0.001, respectively) and a significant decrease of serum endotoxins and isoprostanes (from 157.8±7.6 to 55.5±2.3pg/ml, p<0.001, and from 341±14 to 312±14 pM, p<0.001, respectively). Conversely, no changes for FMD, NOx, serum endotoxins and isoprostanes were observed in controls between baseline and discharge. Changes of FMD significantly correlated with changes of serum endotoxins (Rs=-0.315; p=0.001). CONCLUSIONS The study provides the first evidence that CAP is characterized by impaired FMD with a mechanism potentially involving endotoxin production and oxidative stress.

Temporal trends of time in therapeutic range and incidence of cardiovascular events in patients with non-valvular atrial fibrillation

BACKGROUND Optimal time in therapeutic range (TTR) of vitamin K antagonists (VKAs) is crucial for cardiovascular events (CVEs) prevention in non-valvular atrial fibrillation (NVAF). The relationship between temporal changes of TTR and the incidence of CVEs has been poorly investigated. We investigated 1) temporal trends of TTR in a long-term follow-up of NVAF patients; 2) the incidence of CVEs according to changes of TTR. METHODS Prospective observational study including 1341 NVAF outpatients (mean age 73.5 years, 42.5% male) starting VKAs. Patients were divided into 4 groups: Group 0: Optimal TTR, consistently ≥70% (n = 241); Group 1: Temporally worsening TTR, from above to below 70% (n = 263); Group 2: Temporally improving TTR, from below to above 70% (n = 270); Group 3: Suboptimal TTR, consistently <70% (n = 567). RESULTS In a mean follow-up of 37.7 months (4214.2 patient-years), 108 CVEs occurred (2.6%/year). Survival analysis showed a graded increased risk of CVEs in relation to temporal changes in TTR, with the worst outcomes in Groups 1 and 3 (log-rank test p = 0.013). Multivariable Cox proportional hazards regression analysis showed that Group 1 vs. 0 (HR: 2.096; 95%CI 1.061-4.139, p = 0.033), Group 3 vs. 0 (HR: 2.292; 95%CI 1.205-4.361, p = 0.011), CHA2DS2VASc score (HR:1.316; 95%CI 1.153-1.501, p < 0.001) and PPIs (HR:0.453; 95%CI 0.285-0.721, p = 0.001) were independently associated with CVEs. CONCLUSION A decrease of TTR <70% over time is observed in almost 20% of NVAF patients. Patients with worsening TTR temporally (ie. from initially above 70% to below 70%) have similar risk of CVEs of patients with consistently suboptimal anticoagulation.