The Influence of Hepatitis C Viral Loads on Natural Killer Cell Function.

BACKGROUND: Hepatitis C virus (HCV) infection has a high rate of chronicity, attributable to its capacity to alter host immunity, including natural killer (NK) cell function. In this study, the interaction between NK cell activity and HCV viral load was investigated. METHODS: Peripheral blood NK cells were examined for cytotoxicity and interferon (IFN)-γ expression in HCV infected low (LVL, < 800,000 IU/mL, n = 10) and high (HVL, > 800,000 IU/mL, n = 13) viral load patient cohorts. RESULTS: Spontaneous NK cell cytotoxicity was more robust in the LVL cohort resulting in a negative correlation with viral loads (spontaneous, r = -0.437, P = 0.037; IFN-α activated, r = -0.372, P = 0.081). Although the percent of IFN-γ+ NK cells did not associate with viral load, within the LVL cohort there was a marked increase in IFN-γ+ NK cells upon IFN-α activation relative to medium alone (P < 0.01). To examine the inability of NK cells derived from HVL patients to be further activated, the expression of the exhaustion marker programmed cell death protein (PD)-1 was evaluated. PD-1 expression upon NK cell activation correlated with viral load (r = 0.649, P = 0.009). In addition, HCV proteins upregulated PD-1 expression in vitro (P < 0.05), suggesting that HCV can directly promote NK cell exhaustion. Cells from HVL patients were also more likely to produce IFN-γ in response to HCV core protein. The finding that NK cell PD-1 and IFN-γ expression are linked (r = 0.542, P < 0.05) suggests that increased IFN-γ levels may induce PD-1 as a negative feedback mechanism. CONCLUSIONS: High HCV loads appear to promote NK exhaustion in chronic HCV infection.

Circulating and inducible IL-32α in chronic hepatitis C virus infection.

Background: Interleukin 32 (IL-32) is a recently described pro-inflammatory cytokine implicated in chronic hepatitis C virus (HCV)-related inflammation and fibrosis. IL-32α is the most abundant IL-32 isoform. Methods: Circulating IL-32α levels were documented in patients with chronic HCV infections (n = 31) and compared with individuals who spontaneously resolved HCV infection (n = 14) and HCV-naive controls (n = 20). In addition, peripheral blood mononuclear cells (PBMC) from the chronic HCV (n = 12) and HCV-naive (n = 9) cohorts were investigated for responses to HCV core and non-structural (NS)3 protein induced IL-32α production. Finally, correlations between IL-32α levels, hepatic fibrosis and subsequent responses to interferon-based therapy were documented in patients with chronic HCV. Results: Circulating IL-32α levels in patients with chronic HCV were similar to those of spontaneously resolved and HCV-naive controls. HCV protein induced IL-32α responses were similar in chronic HCV patients and HCV-naive controls. In patients with chronic HCV, serum IL-32α levels correlated with worsening METAVIR fibrosis (F) scores from F0 to F3 (r = 0.596, P < 0.001) as did NS3 induced IL-32α responses (r = 0.837, P < 0.05). However, these correlations were not sustained with the inclusion of IL-32α levels at F4 scores, suggesting events at F4 interfere with IL-32α synthesis or release. In chronic HCV patients who underwent treatment (n = 28), baseline in vivo and in vitro induced IL-32α concentrations were not predictive of therapeutic outcomes. Conclusions: IL-32α activity is associated with worsening fibrosis scores in non-cirrhotic, chronic HCV patients.

Effect of dexamethasone dose and route on the duration of interscalene brachial plexus block for outpatient arthroscopic shoulder surgery: a randomized controlled trial.

PURPOSE: Dexamethasone prolongs the duration of interscalene block, but the benefits of higher doses and perineural vs intravenous administration remain unclear. METHODS: This factorial design, double-blinded trial randomized 280 adult patients undergoing ambulatory arthroscopic shoulder surgery at a single centre in a 1:1:1:1 ratio. Patients received ultrasound-guided interscalene block with 30 mL 0.5% bupivacaine and 4 mg or 8 mg dexamethasone by either the perineural or intravenous route. The primary outcome (block duration measured as the time of first pain at the surgical site) and secondary outcomes (adverse effects, postoperative neurologic symptoms) were assessed by telephone. In this superiority trial, the predetermined minimum clinically important difference for comparisons between doses and routes was 3.0 hr. RESULTS: The perineural route significantly prolonged the mean block duration by 2.0 hr (95% confidence interval [CI], 0.4 to 3.5 hr; P = 0.01), but 8 mg of dexamethasone did not significantly prolong the mean block duration compared with 4 mg (1.3 hr; 95% CI, -0.3 to 2.9 hr, P = 0.10), and there was no significant statistical interaction (P = 0.51). The mean (95% CI) block durations, in hours, were 24.0 (22.9 to 25.1), 24.8 (23.2 to 26.3), 25.4 (23.8 to 27.0), and 27.2 (25.2 to 29.3) for intravenous doses of 4 and 8 mg and perineural doses of 4 and 8 mg, respectively. There were no marked differences in side effects between groups. At 14 postoperative days, 57 (20.4%) patients reported neurologic symptoms, including dyspnea and hoarseness. At six months postoperatively, only six (2.1%) patients had residual symptoms, with four (1.4%) patients' symptoms unlikely related to interscalene block. CONCLUSION: Compared with the intravenous route, perineural dexamethasone prolongs the mean interscalene block duration by a small amount that may or may not be clinically significant, regardless of dose. However, the difference in mean block durations between 8 mg and 4 mg of dexamethasone is highly unlikely to be clinically important, regardless of the administration route. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT02426736). Registered 14 April 2015.

Preliminary analysis of immune activation in early onset type 2 diabetes.

INTRODUCTION: First Nations and other Aboriginal children are disproportionately affected by cardiometabolic diseases, including type 2 diabetes (T2D). In T2D, the disruption of insulin signalling can be driven by pro-inflammatory immunity. Pro-inflammatory responses can be fueled by toll-like receptors (TLR) on immune cells such as peripheral blood mononuclear cells (PBMC, a white blood cell population). TLR4 can bind to lipids from bacteria and food sources activating PBMC to produce cytokines tumour necrosis factor (TNF)-α and interleukin (IL)-1ß. These cytokines can interfere with insulin signalling. Here, we seek to understand how TLR4 activation may be involved in early onset T2D. We hypothesized that immune cells from youth with T2D (n = 8) would be more reactive upon TLR4 stimulation relative to cells from age and body mass index (BMI)-matched controls without T2D (n = 8). METHODS: Serum samples were assayed for adipokines (adiponectin and leptin), as well as cytokines. Freshly isolated PBMC were examined for immune reactivity upon culture with TLR4 ligands bacterial lipopolysaccharide (LPS, 2 and 0.2 ng/ml) and the fatty acid palmitate (200 µM). Culture supernatants were evaluated for the amount of TNF-α and IL-1ß produced by PBMC. RESULTS: Youth with T2D displayed lower median serum adiponectin levels compared to controls (395 vs. 904 ng/ml, p < 0.05). PBMC isolated from youth with and without T2D produced similar levels of TNF-α and IL-1ß after exposure to the higher LPS concentration. However, at the low LPS dose the T2D cohort exhibited enhanced IL-1ß synthesis relative to the control cohort. Additionally, exposure to palmitate resulted in greater IL-1ß synthesis in PBMCs isolated from youth with T2D versus controls (p < 0.05). These differences in cytokine production corresponded to greater monocyte activation in the T2D cohort. CONCLUSION: These preliminary results suggest that cellular immune responses are exaggerated in T2D, particularly with respect to IL-1ß activity. These studies aim to improve the understanding of the biology behind early onset T2D and its vascular complications that burden First Nations people.