Individuals in areas of Plasmodium falciparum endemicity develop immunity to malaria after repeated exposure. Knowledge of the acquisition and nature of protective immune responses to P. falciparum ...is presently limited, particularly for young children. We examined antibodies (IgM, IgG, and IgG subclasses) to merozoite antigens and their relationship to the prospective risk of malaria in children 1 to 4 years of age in a region of malaria endemicity in Papua New Guinea. IgG, IgG1, and IgG3 responses generally increased with age, were higher in children with active infection, and reflected geographic heterogeneity in malaria transmission. Antigenic properties, rather than host factors, appeared to be the main determinant of the type of IgG subclass produced. High antibody levels were not associated with protection from malaria; in contrast, they were typically associated with an increased risk of malaria. Adjustment for malaria exposure, using a novel molecular measure of the force of infection by P. falciparum, accounted for much of the increased risk, suggesting that the antibodies were markers of higher exposure to P. falciparum. Comparisons between antibodies in this cohort of young children and in a longitudinal cohort of older children suggested that the lack of protective association was explained by lower antibody levels among young children and that there is a threshold level of antibodies required for protection from malaria. Our results suggest that in populations with low immunity, such as young children, antibodies to merozoite antigens may act as biomarkers of malaria exposure and that, with increasing exposure and responses of higher magnitude, antibodies may act as biomarkers of protective immunity.
The adherence to and clinical efficacy of pulmonary rehabilitation in idiopathic pulmonary fibrosis (IPF), particularly in comparison with COPD, remains uncertain. The objectives of this real-world ...study were to compare the responses of patients with IPF with a matched group of patients with COPD undergoing the same supervised, outpatient pulmonary rehabilitation program and to determine whether pulmonary rehabilitation is associated with survival in IPF.
Do people with IPF improve to the same extent with pulmonary rehabilitation as a matched group of individuals with COPD, and are noncompletion of or nonresponse to pulmonary rehabilitation, or both, associated with 1-year all-cause mortality in IPF?
Using propensity score matching, 163 patients with IPF were matched 1:1 with a control group of 163 patients with COPD referred for pulmonary rehabilitation. We compared between-group pulmonary rehabilitation completion rates and response. Survival status in the IPF cohort was recorded over 1 year after pulmonary rehabilitation discharge. Cox proportional hazards regression explored the association between pulmonary rehabilitation status and all-cause mortality.
Similar pulmonary rehabilitation completion rates (IPF, 69%; COPD, 63%; P = .24) and improvements in exercise response were observed in both groups with no significant mean between-group differences in incremental shuttle walk test (ISWT) change (mean, 2 m 95% CI, -18 to 22 m). Pulmonary rehabilitation noncompletion (hazard ratio HR, 5.62 95% CI, 2.24-14.08) and nonresponse (HR, 3.91 95% CI, 1.54-9.93) were associated independently with increased 1-year all-cause mortality in IPF.
This real-word study demonstrated that patients with IPF have similar completion rates and magnitude of response to pulmonary rehabilitation compared with a matched group of patients with COPD. In IPF, noncompletion of and nonresponse to pulmonary rehabilitation were associated with increased all-cause mortality. These data reinforce the benefits of pulmonary rehabilitation in patients with IPF.
The purpose of this study was to determine whether thin-capped fibroatheromata (TCFA) identified by virtual histology intravascular ultrasound (VH-IVUS) are associated with major adverse cardiac ...events (MACE) on individual plaque or whole patient analysis.
Post-mortem studies have identified TCFA as the substrate for most myocardial infarctions. However, little is known about the natural history of individual TCFA and their link with MACE. VH-IVUS provides a method of identifying plaques in vivo that are similar (although not identical) to histologically defined TCFA, and has been validated in human atherectomy and post-mortem studies.
One hundred seventy patients with stable angina or troponin-positive acute coronary syndrome referred for percutaneous coronary intervention (PCI) were prospectively enrolled and underwent 3-vessel VH-IVUS pre-PCI and also post-PCI in the culprit vessel. MACE consisted of death, myocardial infarction, or unplanned revascularization.
In all, 30,372 mm of VH-IVUS were analyzed. Eighteen MACE occurred in 16 patients over a median follow-up of 625 days (interquartile range: 463 to 990 days); 1,096 plaques were classified, and 19 lesions resulted in MACE (13 nonculprit lesions and 6 culprit lesions). Nonculprit lesion factors associated with nonrestenotic MACE included VHTCFA (hazard ratio HR: 7.53, p = 0.038) and plaque burden >70% (HR: 8.13, p = 0.011). VHTCFA (HR: 8.16, p = 0.007), plaque burden >70% (HR: 7.48, p < 0.001), and minimum luminal area <4 mm(2) (HR: 2.91, p = 0.036) were associated with total MACE. On patient-based analysis, the only factor associated with nonrestenotic MACE was 3-vessel noncalcified VHTCFA (HR: 1.79, p = 0.004).
VH-IVUS TCFA was associated with nonrestenotic and total MACE on individual plaque analysis, and noncalcified VHTCFA was associated with nonrestenotic and total MACE on whole-patient analysis, demonstrating that VH-IVUS can identify plaques at increased risk of subsequent events. The preservation of the association between VHTCFA and MACE despite various analyses emphasizes its biological importance.
Myocyte necrosis as a result of elective percutaneous coronary intervention (PCI) occurs in approximately one third of cases and is associated with subsequent cardiovascular events. This study ...assessed the ability of remote ischemic preconditioning (IPC) to attenuate cardiac troponin I (cTnI) release after elective PCI.
Two hundred forty-two consecutive patients undergoing elective PCI with undetectable preprocedural cTnI were recruited. Subjects were randomized to receive remote IPC (induced by three 5-minute inflations of a blood pressure cuff to 200 mm Hg around the upper arm, followed by 5-minute intervals of reperfusion) or control (an uninflated cuff around the arm) before arrival in the catheter laboratory. The primary outcome was cTnI at 24 hours after PCI. Secondary outcomes included renal dysfunction and major adverse cardiac and cerebral event rate at 6 months. The median cTnI at 24 hours after PCI was lower in the remote IPC compared with the control group (0.06 versus 0.16 ng/mL; P=0.040). After remote IPC, cTnI was <0.04 ng/mL in 44 patients (42%) compared with 24 in the control group (24%; P=0.01). Subjects who received remote IPC experienced less chest discomfort (P=0.0006) and ECG ST-segment deviation (P=0.005) than control subjects. At 6 months, the major adverse cardiac and cerebral event rate was lower in the remote IPC group (4 versus 13 events; P=0.018).
Remote IPC reduces ischemic chest discomfort during PCI, attenuates procedure-related cTnI release, and appears to reduce subsequent cardiovascular events.
Naturally acquired humoral immunity to the malarial parasite Plasmodium falciparum can protect against disease, although the precise mechanisms remain unclear. Although antibody levels can be ...measured by ELISA, few studies have investigated functional antibody assays in relation to clinical outcomes. In this study we applied a recently developed functional assay of antibody-mediated opsonisation of merozoites, to plasma samples from a longitudinal cohort study conducted in a malaria endemic region of Papua New Guinea (PNG). Phagocytic activity was quantified by flow cytometry using a standardized and high-throughput protocol, and was subsequently evaluated for association with protection from clinical malaria and high-density parasitemia. Opsonising antibody responses were found to: i) increase with age, ii) be enhanced by concurrent infection, and iii) correlate with protection from clinical episodes and high-density parasitemia. Stronger protective associations were observed in individuals with no detectable parasitemia at baseline. This study presents the first evidence for merozoite phagocytosis as a correlate of acquired immunity and clinical protection against P. falciparum malaria.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
γδ T cells are important for both protective immunity and immunopathogenesis during malaria infection. However, the immunological processes determining beneficial or detrimental effects on disease ...outcome remain elusive. The aim of this study was to examine expression and regulatory effect of the inhibitory receptor T-cell immunoglobulin domain and mucin domain 3 (TIM3) on γδ T cells. While TIM3 expression and function on conventional αβ T cells have been clearly defined, the equivalent characterization on γδ T cells and associations with disease outcomes is limited. This study investigated the functional capacity of TIM3+ γδ T cells and the underlying mechanisms contributing to TIM3 upregulation and established an association with malaria disease outcomes.
We analyzed TIM3 expression on γδ T cells in 132 children aged 5-10 years living in malaria endemic areas of Papua New Guinea. TIM3 upregulation and effector functions of TIM3+ γδ T cells were assessed following in vitro stimulation with parasite-infected erythrocytes, phosphoantigen and/or cytokines. Associations between the proportion of TIM3-expressing cells and the molecular force of infection were tested using negative binomial regression and in a Cox proportional hazards model for time to first clinical episode. Multivariable analyses to determine the association of TIM3 and IL-18 levels were conducted using general linear models. Malaria infection mouse models were utilized to experimentally investigate the relationship between repeated exposure and TIM3 upregulation.
This study demonstrates that even in the absence of an active malaria infection, children of malaria endemic areas have an atypical population of TIM3-expressing γδ T cells (mean frequency TIM3+ of total γδ T cells 15.2% ± 12). Crucial factors required for γδ T cell TIM3 upregulation include IL-12/IL-18, and plasma IL-18 was associated with TIM3 expression (P = 0.002). Additionally, we show a relationship between TIM3 expression and infection with distinct parasite clones during repeated exposure. TIM3+ γδ T cells were functionally impaired and were associated with asymptomatic malaria infection (hazard ratio 0.54, P = 0.032).
Collectively our data demonstrate a novel role for IL-12/IL-18 in shaping the innate immune response and provide fundamental insight into aspects of γδ T cell immunoregulation. Furthermore, we show that TIM3 represents an important γδ T cell regulatory component involved in minimizing malaria symptoms.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background and Objective
Gait speed is associated with survival in individuals with idiopathic pulmonary fibrosis (IPF). The extent to which four‐metre gait speed (4MGS) decline predicts adverse ...outcome in IPF remains unclear. We aimed to examine longitudinal 4MGS change and identify a cut‐point associated with adverse outcome.
Methods
In a prospective cohort study, we recruited 132 individuals newly diagnosed with IPF and measured 4MGS change over 6 months. Death/first hospitalization at 6 months were composite outcome events. Complete data (paired 4MGS plus index event) were available in 85 participants; missing 4MGS data were addressed using multiple imputation. Receiver‐Operating Curve plots identified a 4MGS change cut‐point. Cox proportional‐hazard regression assessed the relationship between 4MGS change and time to event.
Results
4MGS declined over 6 months (mean 95% CI change: −0.05 −0.09 to −0.01 m/s; p = 0.02). A decline of 0.07 m/s or more in 4MGS over 6 months had better discrimination for the index event than change in 6‐minute walk distance, forced vital capacity, Composite Physiologic Index or Gender Age Physiology index. Kaplan–Meier curves demonstrated a significant difference in time to event between 4MGS groups (substantial decline: >−0.07 m/s versus minor decline/improvers: ≤−0.07 m/s; p = 0.007). Those with substantial decline had an increased risk of hospitalization/death (adjusted hazard ratio 95% CI 4.61 1.23–15.83). Similar results were observed in multiple imputation analysis.
Conclusion
In newly diagnosed IPF, a substantial 4MGS decline over 6 months is associated with shorter time to hospitalization/death at 6 months. 4MGS change has potential as a surrogate endpoint for interventions aimed at modifying hospitalization/death.
In people newly diagnosed with IPF, four‐metre gait speed (4MGS) declined significantly over 6 months. A decline of more than 0.07 m/s was associated with shorter time to hospitalization/death over the subsequent 6 months. 4MGS change has potential as a surrogate endpoint for interventions aimed at modifying hospitalization/death in IPF.
See related editorial
Coronary computed tomography angiography (CCTA) can identify high-risk coronary plaque types. However, the inter-observer variability for high-risk plaque features, including low attenuation plaque ...(LAP), positive remodelling (PR), and the Napkin-Ring sign (NRS), may reduce their utility, especially amongst less experienced readers.
In a prospective study, we compared the prevalence, location and inter-observer variability of both conventional CT-defined high-risk plaques with a novel index based on quantifying the ratio of necrotic core to fibrous plaque using individualised X-ray attenuation cut-offs (the CT-defined thin-cap fibroatheroma - CT-TCFA) in 100 patients followed-up for 7 years.
In total, 346 plaques were identified in all patients. Seventy-two (21%) of all plaques were classified by conventional CT parameters as high-risk (either NRS or PR and LAP combined), and 43 (12%) of plaques were considered high-risk using the novel CT-TCFA definition of (Necrotic Core/fibrous plaque ratio of >0.9). The majority (80%) of the high-risk plaques (LAP&PR, NRS and CT-TCFA) were located in the proximal and mid-LAD and RCA. The kappa co-efficient of inter-observer variability (k) for NRS was 0.4 and for PR and LAP combined 0.4. While the kappa co-efficient of inter-observer variability (k) for the new CT-TCFA definition was 0.7. During follow-up, patients with either conventional high-risk plaques or CT-TCFAs were significantly more likely to have MACE (Major adverse cardiovascular events) compared to patients without coronary plaques (p value 0.03 & 0.03, respectively).
The novel CT-TCFA is associated with MACE and has improved inter-observer variability compared with current CT-defined high-risk plaques.
•We define a novel high-risk coronary plaque, the CT-TCFA based on the CT-defined ratio of necrotic core to fibrous plaque.•CT-TCFA significantly overlap with current CT-defined high-risk coronary plaque with a predilection to proximal coronaries.•The inter-observer variability of CT-TCFAs is lower than conventional CT-defined high-risk coronary plaques.•The presence of CT-TCFA is associated with increased MACE over long term follow up.
The EuroQoL 5D (EQ-5D) has been widely used in studies of cardiac disease, but its measurement properties in this group are not well established. The study aimed to quantify the relationship between ...measures commonly used in studies of cardiac disease and the EQ-5D index across different levels of disease severity.
Patient-level data from 7 studies of cardiac interventions were used, which included randomised trials and observational studies. Relationships between the EQ-5D index and commonly used cardiac measures, Canadian Cardiovascular Society (CCS) angina severity class, treadmill exercise time (ETT) and scales of the Seattle Angina Questionnaire (SAQ) were examined. Mixed effects linear regression was used to assess these relationships, with the EQ-5D index as the response.
Study sample sizes ranged from 68 to 2419. Mean baseline EQ-5D index ranged from 0.77 in patients at diagnosis (95% CI 0.75, 0.78) to 0.43 in patients with advanced disease (95% CI 0.39, 0.48) and differed significantly across studies (p < 0.001). There was evidence of a ceiling effect in patients at diagnosis. The minimum clinically important difference of a one minute increase in ETT was associated with a 0.019 (95% CI 0.014, 0.025) increase in EQ-5D index. One class increase in CCS was associated with a 0.11 (95% CI 0.09, 0.13) decrease in EQ-5D index. A 10 unit increase in SAQ scales was associated with increases between 0.04 and 0.07 in EQ-5D index (95% CIs 0.03, 0.05 and 0.05, 0.08). Tests of heterogeneity indicated the EQ-5D-covariate relationships were consistent across levels of disease severity for ETT and the treatment satisfaction scale of the SAQ, but heterogeneous for age, gender, CCS angina class and other scales of the SAQ.
The EQ-5D index varies with coronary disease severity. The relationship between the EQ-5D index and an outcome measure used in cardiac intervention studies, ETT, was consistent across disease severity levels, but the relationship between demographic variables, CCS angina class and most of the SAQ scales and the EQ-5D index was heterogeneous for patients with different levels of coronary disease. Differences in the EQ-5D index associated with clinically important differences in cardiac measures can be quantified and vary between three important examples - angina class, ETT and SAQ.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Multivariate analysis of 1H-NMR spectra of blood sera was reported previously to predict angiographically defined advanced coronary artery disease (CAD) with >90% accuracy and specificity. The ...analysis depended mainly on the major lipid regions of the spectra, but many variables, including gender and drug treatment, affect lipid composition and are potential confounders. We have determined the predictive power of the same methodology for angiographically defined CAD using plasma samples from groups of male patients, classified by statin treatment, who had normal coronary arteries (NCAs) or CAD. Predictions for NCA and CAD groups were only 80.3% correct for patients not treated with statins and 61.3% for treated patients, compared with random correct predictions of 50%. A confidence limit of >99% was achieved for 36.2% of predictions for untreated groups and 6.2% for treated groups. Detection of CAD by 1H-NMR with >99% confidence was therefore very weak compared with angiography.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
PDF
