Stroke-induced immunodepression and dysphagia independently predict stroke-associated pneumonia - The PREDICT study

Predictive value of a novel pragmatic tool for post-stroke aspiration risk: The Functional Bedside Aspiration Screen

BACKGROUND

There is still a strong need for an optimal clinician-friendly screening tool for the identification of aspiration risk in stroke patients. In this study, we present the development of a novel, context-specific screening tool for the prediction of aspiration risk on recent stroke survivors, the Functional Bedside Aspiration Screen (FBAS), and examine its construct validity, reliability with the predictive values toward pragmatic patients' outcomes.

METHODS

We conducted a prospective validation study of 104 acute ischemic stroke patients admitted to clinical wards in a tertiary university hospital. A group of experts developed and administered the FBAS 10-point scale to all patients. Outcome measures were compared with those of the validated Yale Swallow Protocol (YSP, reference measure) and health indicators.

KEY RESULTS

A strong association was found between the FBAS cutoff criterion and the YSP (Pearson χ²  = 54.92, P < .001). A score of ≤8 on the FBAS presented with 93.3% sensitivity and 83.3% specificity in deeming patient with reduced safety for oral nutrition (AUC = 0.934, CI = 0.884-0.985). An inverse relationship was found between performance on the FBAS and in-hospital and long-term outcome indicators. Patients who failed the FBAS were 1.82 times more likely to develop aspiration pneumonia (95% CI = 1.42-2.35) and 1.35 times more likely to develop pneumonia within 3 months postonset (95% CI = 1.15-1.59).

CONCLUSIONS AND INFERENCES

The FBAS is a potentially useful tool for timely prediction of aspiration risk and health outcome in acute stroke.

Neuroimmune crosstalk in central nervous system injury-induced infection and pharmacological intervention

Infection (such as pneumonia and urinary tract infection) is one of the leading causes of death in patients with acute central nervous system (CNS) injury, which also greatly affects the patients' prognosis and quality of life. Antibiotics are commonly used for the treatment of various infections, however, available evidence demonstrate that prophylactic antibiotic treatments for CNS injury-induced infection have been unsuccessful. Effective approaches for prevention of CNS injury induced-infection remain scarce, therefore, better understanding the molecular and cellular mechanisms of infection post-CNS injury may aid in the development of efficacious therapeutic options. CNS injury-induced infection is confirmed affected by the sympathetic/parasympathetic nervous system, hypothalamic-pituitary-adrenal axis, and even brain-gut axis. In this review, we summarized the mechanisms of CNS injury- induced infection, crosstalk between the CNS and the immune system and current pharmacological intervention to provide ideas for the development of new anti- infective therapeutic strategies.

Factors Associated with Risk of Stroke-Associated Pneumonia in Patients with Dysphagia: A Systematic Review

Dysphagia is associated with increased risk of stroke-associated pneumonia (SAP). However, it is unclear what other factors contribute to that risk or which measures may reduce it. This systematic review aimed to provide evidence on interventions and care processes associated with SAP in patients with dysphagia. Studies were screened for inclusion if they included dysphagia only patients, dysphagia and non-dysphagia patients or unselected patients that included dysphagic patients and evaluated factors associated with a recorded frequency of SAP. Electronic databases were searched from inception to February 2017. Eligible studies were critically appraised. Heterogeneity was evaluated using I². The primary outcome was SAP. Eleven studies were included. Sample sizes ranged from 60 to 1088 patients. There was heterogeneity in study design. Measures of immunodepression are associated with SAP in dysphagic patients. There is insufficient evidence to justify screening for aerobic Gram-negative bacteria. Prophylactic antibiotics did not prevent SAP and proton pump inhibitors may increase risk. Treatment with metoclopramide may reduce SAP risk. Evidence that nasogastric tube (NGT) placement increases risk of SAP is equivocal. A multidisciplinary team approach and instrumental assessment of swallowing may reduce risk of pneumonia. Patients with impaired mobility were associated with increased risk. Findings should be interpreted with caution given the number of studies, heterogeneity and descriptive analyses. Several medical interventions and care processes, which may reduce risk of SAP in patients with dysphagia, have been identified. Further research is needed to evaluate the role of these interventions and care processes in clinical practice.

Biomarkers of immune capacity, infection and inflammation are associated with poor outcome and mortality after stroke - the PREDICT study

Background

Almost 40% of stroke patients have a poor outcome at 3 months after the index event. Predictors for stroke outcome in the early acute phase may help to tailor stroke treatment. Infection and inflammation are considered to influence stroke outcome.

Methods

In a prospective multicenter study in Germany and Spain, including 486 patients with acute ischemic stroke, we used multivariable regression analysis to investigate the association of poor outcome with monocytic HLA-DR (mHLA-DR) expression, interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-alpha) and lipopolysaccharide-binding protein (LBP) as markers for immunodepression, inflammation and infection. Outcome was assessed at 3 months after stroke via a structured telephone interview using the modified Rankin Scale (mRS). Poor outcome was defined as a mRS score of 3 or higher which included death. Furthermore, a time-to-event analysis for death within 3 months was performed.

Results

Three-month outcome data was available for 391 patients. Female sex, older age, diabetes mellitus, atrial fibrillation, stroke-associated pneumonia (SAP) and higher National Institute of Health Stroke Scale (NIHSS) score as well as lower mHLA-DR levels, higher IL-6 and LBP-levels at day 1 were associated with poor outcome at 3 months in bivariate analysis. Furthermore, multivariable analysis revealed that lower mHLA-DR expression was associated with poor outcome.

Female sex, older age, atrial fibrillation, SAP, higher NIHSS score, lower mHLA-DR expression and higher IL-6 levels were associated with shorter survival time in bivariate analysis. In multivariable analysis, SAP and higher IL-6 levels on day 1 were associated with shorter survival time.

Conclusions

SAP, lower mHLA-DR-expression and higher IL-6 levels on day one are associated with poor outcome and shorter survival time at 3 months after stroke onset.

Trial registration

www.clinicaltrials.gov, NCT01079728, March 3, 2010.

Fluid Balance Variations During the Early Phase of Large Hemispheric Stroke Are Associated With Patients' Functional Outcome

Background: From the variety of factors underlying the ischemia-associated edema formation in large hemispheric stroke (LHS), an increased brain water content during the early phase seems to have a pivotal role for long-lasting tissue damage. However, the importance of the fluid management during the acute phase of LHS has so far not been adequately studied. Therefore, this study explored the association between the fluid balance and functional outcome in patients suffering from LHS. Methods: We analyzed hospital-based medical records of 39 consecutive patients with LHS and decompressive hemicraniectomy. Over the first 10 days after admission, the volumes of all administered fluids were assessed daily and corrected for daily urinary output and insensible loss. Functional outcome at 3 months was assessed with the modified Rankin Scale (mRS) and dichotomized into an acceptable (mRS ≤ 4) vs. a poor outcome (mRS ≥ 5). Results: Compared to patients with a poor functional outcome (n = 19), those with an acceptable outcome (n = 20) were characterized by a significantly lower cumulative net fluid balance at day 5 (1.6 ± 2.5 vs. 3.4 ± 4.4 l), day 7 (2.0 ± 2.9 vs. 4.6 ± 5.2 l), and day 10 (0 ± 2.5 vs. 5.6 ± 6.2 l). In addition to age, only the cumulative net fluid balance at day 10 served as an independent factor for poor functional outcome in multiple regression analyses. Conclusion: These data provide evidence for a critical role of the early phase net fluid balance with respect to the functional outcome after LHS. This observation leads to the hypothesis that patients with LHS might benefit from a more restrictive volume therapy. However, prospective studies are warranted to establish a causal relationship and recommendations for treatment strategies.

Old Dog New Tricks; Revisiting How Stroke Modulates the Systemic Immune Landscape

Infections in the post-acute phase of cerebral ischaemia impede optimal recovery by exacerbating morbidity and mortality. Our review aims to reconcile the increased infection susceptibility of patients post-stroke by consolidating our understanding of compartmentalised alterations to systemic immunity. Mounting evidence has catalogued alterations to numerous immune cell populations but an understanding of the mechanisms of long-range communication between the immune system, nervous system and other organs beyond the involvement of autonomic signalling is lacking. By taking our cues from established and emerging concepts of neuro-immune interactions, immune-mediated inter-organ cross-talk, innate immune training and the role of microbiota-derived signals in central nervous system (CNS) function we will explore mechanisms of how cerebral ischaemia could shape systemic immune function. In this context, we will also discuss a key question: how are immune requirements critical for mediating repair of the ischaemic insult balanced by the need for anti-microbial immunity post-stroke, given that they are mediated by mutually exclusive immune networks? Our reformed understanding of the immune landscape post-stroke and novel mechanisms at play could guide targeted therapeutic interventions and initiate a step-change in the clinical management of these infectious complications post-stroke.

Systemic inflammation in hemorrhagic strokes - A novel neurological sign and therapeutic target?

Growing evidences suggest that stroke is a systemic disease affecting many organ systems beyond the brain. Stroke-related systemic inflammatory response and immune dysregulations may play an important role in brain injury, recovery, and stroke outcome. The two main phenomena in stroke-related peripheral immune dysregulations are systemic inflammation and post-stroke immunosuppression. There is emerging evidence suggesting that the spleen contracts following ischemic stroke, activates peripheral immune response and this may further potentiate brain injury. Whether similar brain-immune crosstalk occurs in hemorrhagic strokes such as intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) is not established. In this review, we systematically examined animal and human evidence to date on peripheral immune responses associated with hemorrhagic strokes. Specifically, we reviewed the impact of clinical systemic inflammatory response syndrome (SIRS), inflammation- and immune-associated biomarkers, the brain-spleen interaction, and cellular mediators of peripheral immune responses to ICH and SAH including regulatory T cells (Tregs). While there is growing data suggesting that peripheral immune dysregulation following hemorrhagic strokes may be important in brain injury pathogenesis and outcome, details of this brain-immune system cross-talk remain insufficiently understood. This is an important unmet scientific need that may lead to novel therapeutic strategies in this highly morbid condition.

IL-6 Plasma Levels Correlate With Cerebral Perfusion Deficits and Infarct Sizes in Stroke Patients Without Associated Infections

Introduction: We aimed to investigate several blood-based biomarkers related to inflammation, immunity, and stress response in a cohort of patients without stroke-associated infections regarding their predictive abilities for functional outcome and explore whether they correlate with MRI markers, such as infarct size or location. Methods: We combined the clinical and radiological data of patients participating in two observational acute stroke cohorts: the PREDICT and 1000Plus studies. The following blood-based biomarkers were measured in these patients: monocytic HLA-DR, IL-6, IL-8, IL-10, LBP, MRproANP, MRproADM, CTproET, Copeptin, and PCT. Multiparametric stroke MRI was performed including T2^*, DWI, FLAIR, TOF-MRA, and perfusion imaging. Standard descriptive sum statistics were used to describe the sample. Associations were analyzed using Fischer's exact test, independent samples t-test and Spearmans correlation, where appropriate. Results: Demographics and stroke characteristics were as follows: 94 patients without infections, mean age 68 years (SD 10.5), 32.2% of subjects were female, median NIHSS score at admission 3 (IQR 2-5), median mRS 3 months after stroke 1 (IQR 0-2), mean volume of DWI lesion at admission 5.7 ml (SD 12.8), mean FLAIR final infarct volume 10 ml (SD 14.9), cortical affection in 61% of infarctions. Acute DWI lesion volume on admission MRI was moderately correlated to admission/maximum IL-6 as well as maximum LBP. Extent of perfusion deficit and mismatch were moderately correlated to admission/maximum IL-6 levels. Final lesion volume on FLAIR was moderately correlated to admission IL-6 levels. Conclusion: We found IL-6 to be associated with several parameters from acute stroke MRI (acute DWI lesion, perfusion deficit, final infarct size, and affection of cortex) in a cohort of patients not influenced by infections. Clinical Trial Registration: www.ClinicalTrials.gov, identifiers NCT01079728 and NCT00715533.

T-lymphocyte subsets as a predictive biomarker for stroke-associated pneumonia

The aim of this study was to facilitate the clinical treatment and prognosis of stroke-associated pneumonia (SAP) by examining changes in T-lymphocyte subsets. Stroke patients admitted in Suzhou Hospital between 2014 and 2016 participated in the study. Patients were divided into a pneumonia group (50 patients) and a non-pneumonia group (254 patients) based on a diagnosis of pneumonia. Information regarding risk factors for ischemic stroke was collected from all patients using a questionnaire. Compared with non-SAP patients, SAP patients were older, dysphagic, smokers, had higher NIH stroke scale (NIHSS) scores and neutrophil: lymphocyte ratio, had higher leukocyte, neutrophil, and CD8 levels, had lower CD3, CD4, and lymphocyte levels, and had a lower CD4:CD8 ratio. Patients with a higher NIHSS score had higher CD8 levels, lower CD3 and CD4 levels, and a lower CD4:CD8 ratio. No significant differences in T-lymphocyte subsets were found between the left and right cerebral hemispheres. After adjusting for other variables, smoking, dysphagia, NIHSS score, and CD4:CD8 ratio were positively associated with SAP. The areas under the receiver operating characteristic curve for dysphagia, NIHSS score, CD4:CD8 ratio, CD4:CD8 ratio + NIHSS score, and Dysphagia+ CD4:CD8 ratio + NIHSS score were 0.583 (95% CI: 0.490-0.675), 0.791 (95% CI: 0.724-0.859), 0.676 (95% CI: 0.593-0.759), 0.846 (95% CI: 0.790-0.902), and 0.867 (95% CI: 0.815-0.918), respectively. A few T-lymphocyte subsets may increase susceptibility to pneumonia after acute ischemic stroke. Thus, the detection of T-lymphocyte subsets may predict the risk of SAP in such patients.

Exploratory Investigation of Intestinal Function and Bacterial Translocation After Focal Cerebral Ischemia in the Mouse

Background and Purpose: The gut communicates with the brain bidirectionally via neural, humoral and immune pathways. All these pathways are affected by acute brain lesions, such as stroke. Brain-gut communication may therefore impact on the overall outcome after CNS-injury. Until now, contradictory reports on intestinal function and translocation of gut bacteria after experimental stroke have been published. Accordingly, we aimed to specifically investigate the effects of transient focal cerebral ischemia on intestinal permeability, gut associated lymphoid tissue and bacterial translocation in an exploratory study using a well-characterized murine stroke model.

Methods: After 60 min of middle cerebral artery occlusion (MCAO) we assessed intestinal morphology (time points after surgery day 0, 3, 5, 14, 21) and tight junction protein expression (occludin and claudin-1 at day 1 and 3) in 12-week-old male C57Bl/6J mice. Lactulose/mannitol/sucralose test was performed to assess intestinal permeability 24–72 h after surgery. To investigate the influence of cerebral ischemia on the local immune system of the gut, main immune cell populations in Peyer's patches (PP) were quantified by flow cytometry. Finally, we evaluated bacterial translocation to extraintestinal organs 24 and 72 h after MCAO by microbiological culture and fluorescence in situ hybridization targeting bacterial 16S rRNA.

Results: Transient MCAO decreased claudin-1 expression in the ileum but not in the colon. Intestinal morphology (assessed by light microscopy) and permeability did not change measurably after MCAO. After MCAO, animals had significantly fewer B cells in PP compared to naïve mice.

Conclusions: In a murine model of stroke, which leads to large brain infarctions in the middle cerebral artery territory, we did not find evidence for overt alterations neither in gut morphology, barrier proteins and permeability nor presence of intestinal bacterial translocation.

Chronic Obstructive Pulmonary Disease and Stroke

Chronic obstructive pulmonary disease (COPD) is currently the fourth leading cause of death in the world and its incidence and prevalence is on the rise. It is evident that COPD is linked to cardiovascular disease. In the last years, several studies demonstrated that COPD may also be a risk factor for stroke, another major cause of death worldwide. Taking in consideration that COPD has multiple comorbidities it is hard to say whether COPD is an independent risk factor for stroke or it is due to confounding effect. This review is aimed to discuss current data on COPD and stroke, potential links, therapy, and prevention. Current data suggest that COPD may increase the risk of hemorrhagic stroke. The incidence of other stroke subtypes may also be increased in COPD or may be due to confounding effect. However, COPD patients who have stroke are at risk for pulmonary and extrapulmonary complications. We conclude that more studies are needed to further clarify the links between COPD and stroke. The management of COPD as well as the use of prevention therapy is essential to decrease the risk for stroke and should be at special attention in pulmonary medicine and neurology.

Complex interplay of multiple biological systems that contribute to post-stroke infections

Stroke is a leading contributor of death and disability around the world. Despite its recognised debilitating neurological deficits, a devastating clinical complication of surviving stroke patients that needs more attention is infection. Up to half of the patients develop infections after stroke, and a high proportion of them will die as a direct consequence. Major clinical trials that examined preventive antibiotic therapy in stroke patients have demonstrated this method of prevention is not effective as it does not reduce incidence of post-stroke pneumonia or improve patient outcome. Additionally, retrospective studies evaluating the use of β-blockers for the modulation of the sympathetic nervous system to prevent post-stroke infections have given mixed results. Therefore, there is an urgent need for more effective therapeutic options that target the underlying mechanisms of post-stroke infections. The understanding that infections are largely attributable to the "stroke-induced systemic immunosuppression" phenomenon has begun to emerge, and thus, exploring the pathways that trigger post-stroke immunosuppression is expected to reveal potential new therapeutics. As such, we will outline the impacts that stroke has on several biological systems in this review, and discuss how these contribute to host susceptibility to infection after stroke. Furthermore, the emerging role of the gut and its microbiota has recently come to surface and intensifies the complex pathways to post-stroke infection. Finally, we identify potential avenues to combat infection that target the pathways of stroke-induced systemic immunosuppression to ultimately improve stroke patient outcome.

Identifying unmet needs in long-term stroke care using in-depth assessment and the Post-Stroke Checklist - The Managing Aftercare for Stroke (MAS-I) study

Introduction

Detailed data on the long-term consequences and treatment of stroke are scarce. We aimed to assess the needs and disease burden of community-dwelling stroke patients and their carers and to compare their treatment to evidence-based guidelines by a stroke neurologist.

Methods

We invited long-term stroke patients from two previous acute clinical studies (n = 516) in Berlin, Germany to participate in an observational, cross-sectional study. Participants underwent a comprehensive interview and examination using the Post-Stroke Checklist and validated standard measures of: self-reported needs, quality of life, overall outcome, spasticity, pain, aphasia, cognition, depression, secondary prevention, social needs and caregiver burden.

Results

Fifty-seven participants (median initial National Institutes of Health Stroke Scale score 10 interquartile range 4-12.75) consented to assessment (median 41 months (interquartile range 36-50) after stroke. Modified Rankin Scale was 2 (median; interquartile range 1-3), EuroQoL index value was 0.81 (median; interquartile range 0.70-1.00). The frequencies for disabilities in the major domains were: spasticity 35%; cognition 61%; depression 20%; medication non-compliance 14%. Spasticity (p = 0.008) and social needs (p < 0.001) had the strongest impact on quality of life. The corresponding items in the Post-Stroke Checklist were predictive for low mood (p < 0.001), impaired cognition (p = 0.015), social needs (p = 0.005) and caregiver burden (p = 0.031). In the comprehensive interview, we identified the following needs: medical review (30%), optimization of pharmacotherapy (18%), outpatient therapy (47%) and social work input (33%).

Conclusion

These results suggest significant unmet needs and gaps in health and social care in long-term stroke patients. Further research to develop a comprehensive model for managing stroke aftercare is warranted.Clinical Trial Registration: clinicaltrials.gov NCT02320994.

β-arrestin2 functions as a key regulator in the sympathetic-triggered immunodepression after stroke

Background

Stroke-induced immunodeficiency syndrome (SIDS) is regarded as a protective mechanism for secondary inflammatory injury as well as a contributor to infection complications. Although stroke-induced hyperactivation of the sympathetic system is proved to facilitate SIDS, the involved endogenous factors and pathways are largely elusive. In this study, we aim to investigate the function of beta-arrestin-2 (ARRB2) in the sympathetic-mediated SIDS.

Methods

Splenic ARRB2 expression and the sympathetic system activity were detected after establishing transient models of middle cerebral artery occlusion (MCAO). In addition, a correlation between ARRB2 expression and the sympathetic system activity was analyzed using a linear correlation analysis. Any SIDS reflected in monocyte dysfunction was investigated by measuring inflammatory cytokine secretion and neurological deficit scores and infarct volume were tested to assess neurological outcome. Further, ARRB2 expression in the monocytes was knocked down in vitro by siRNAs. Following the stimulation of noradrenaline and lipopolysaccharide, cytokine secretion and the nuclear factor-κB (NF-κB) pathway were evaluated to gain insight into the mechanisms related to the contribution of ARRB2 to adrenergic-induced monocyte dysfunction.

Results

Splenic ARRB2 expression was significantly increased after stroke and also showed a significant positive correlation with the sympathetic system activity. Stroke-induced monocyte dysfunction resulted in an increase of the interleukin-10 (IL-10) level as well as a decrease of the interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels. Also, blockade of adrenergic-activity significantly reversed these cytokine levels, and blockade of adrenergic-activity improved stroke-induced neurological results. However, the improved neurological results had no significant correlation with ARRB2 expression. Furthermore, the in vitro results showed that the deficiency of ARRB2 dramatically repealed adrenergic-induced monocyte dysfunction and the inhibition of NF-κB signaling phosphorylation activity.

Conclusions

ARRB2 is implicated in the sympathetic-triggered SIDS, in particular, monocyte dysfunction after stroke. Accordingly, ARRB2 may be a promising therapeutic target for the immunological management of stroke in a clinic.

The Effect of Improved Dysphagia Care on Outcome in Patients with Acute Stroke: Trends from 8-Year Data of a Large Stroke Register

BACKGROUND

Early dysphagia screening and appropriate management are recommended by current guidelines to reduce complications and case fatality in acute stroke. However, data on the potential benefit of changes in dysphagia care on patient outcome are limited. Our objective was to assess the degree of implementation of dysphagia guidelines and determine the impact of modifications in dysphagia screening and treatment practices on disease complications and outcome in stroke patients over time.

METHODS

In this prospective register-based study ("Stroke Register of Northwestern Germany"), all adult stroke patients admitted to 157 participating hospitals between January, 2008 and December, 2015 were included (n = 674,423). Dysphagia incidence upon admission, the proportion of patients receiving a standardized swallowing screening, and the percentage of dysphagic patients being referred to a speech language therapist (SLT) for treatment were obtained per year. Pneumonia rate, modified Rankin Scale (mRS) at discharge, and in-hospital mortality were compared between groups of dysphagic vs. non-dysphagic patients over time.

RESULTS

Screening proportions continuously increased from 47.2% in 2008 to 86.6% in 2015. But the proportion diagnosed with dysphagia remained stable with about 19%. The number of dysphagic patients receiving SLT treatment grew from 81.6 up to 87.0%. Pneumonia incidence was higher in dysphagic stroke cases (adjusted OR 5.4 [5.2-5.5], p < 0.001), accompanied by a worse mRS at discharge (adjusted OR for mRS ≥3: 3.1 [3.0-3.1], p < 0.001) and higher mortality (adjusted OR 3.1 [3.0-3.2], p < 0.001). The order of magnitude of these end points did not change over time.

CONCLUSION

Although advances have been made in dysphagia care, prevalent screening and treatment practices remain insufficient to reduce pneumonia rate, improve functional outcome, and decrease case fatality in dysphagic stroke patients. More research is urgently needed to develop more effective swallowing therapies.

Unilateral Vocal Fold Paralysis and Risk of Pneumonia: A Nationwide Population-Based Cohort Study

Objective To investigate pneumonia risk among patients with unilateral vocal fold paralysis (UVFP). Study Design Retrospective population-based cohort study. Setting This study used data from the National Health Insurance Research Database of Taiwan, a nationwide population-based database. Subjects and Methods A total of 419 patients newly diagnosed with UVFP between January 1, 1997, and December 31, 2013, were identified from the Longitudinal Health Insurance Database 2000, a nationally representative database of 1 million randomly selected patients. Moreover, 1676 patients without UVFP were matched to patients with UVFP at a 1:4 ratio based on age, sex, socioeconomic status, urbanization level, and site-specific cancers. Patients were followed up until death or the end of the study period (December 31, 2013). The primary outcome was the occurrence of pneumonia. Results The cumulative incidence of pneumonia was significantly higher for patients with UVFP than those without UFVP ( P < .001). The adjusted Cox proportional hazard model showed that UVFP was significantly associated with a higher incidence of pneumonia (hazard ratio, 1.97; 95% CI, 1.35-2.86; P < .001). Subgroup analyses demonstrated that UVFP was an independent risk factor of pneumonia for 4 subgroups: young (18-50 years), older (≥51 years), male, and cancer. Conclusion This is the first nationwide population-based cohort study to investigate the association between UVFP and pneumonia. The findings indicate that UVFP is an independent risk factor of pneumonia. Given the study results, physicians should be aware of the potential for pneumonia occurrence following UVFP.

Lymphocyte-to-monocyte ratio on day 7 is associated with outcomes in acute ischemic stroke

The main features of stroke-induced immunosuppression are lymphopenia and deactivation of monocytes in peripheral blood. We hypothesized that lymphocyte-to-monocyte ratio (LMR) in peripheral blood may represent the degree of stroke-induced immunosuppression. To prove this hypothesis, we evaluated whether LMR is associated with risk of post-stroke infection and clinical outcome at 3 months in patients with acute ischemic stroke. We selected patients with stroke in anterior circulation within 24 h from onset. Peripheral blood sampling for differential blood count was performed on days 1 and 7. The LMRs on days 1 and 7 were analyzed to determine associations with excellent outcomes (modified Rankin Scale of score 0-1 at 3 months). One hundred and two patients were included. The initial National Institutes of Health Stroke Scale score (adjusted odd ratio [OR] 0.89; 95% confidence interval [CI], 0.83-0.95; P = 0.001) and LMR on day 7 (adjusted OR 1.49; 95% CI, 1.09-2.02; P = 0.011) were associated with excellent outcomes. LMRs on day 1 were significantly lower in stroke patients with pneumonia (P = 0.007) and pneumonia or urinary tract infection (P = 0.012) than those without infections. LMRs on day 7 were also significantly lower in stroke patients with infection (P = 0.005 in pneumonia, P = 0.003 in urinary tract infection, and P < 0.001 in pneumonia or urinary tract infection) than those without infections. Lower LMRs on day 7 are associated with worse outcomes at 3 months after stroke onset. LMR may be a useful marker for assessing the stroke-induced immunosuppression.

Assessment of immune organ dysfunction in critical illness: utility of innate immune response markers

In critically ill patients, organ dysfunctions are routinely assessed, monitored, and treated. Mounting data show that substantial critical illness-induced changes in the immune system can be observed in most ICU patients and that not only "hyper-inflammation" but also persistence of an anti-inflammatory phenotype (as in sepsis-associated immunosuppression) is associated with increased morbidity and mortality. Despite common perception, changes in functional immunity cannot be adequately assessed by routine inflammatory biomarkers such as C-reactive protein, procalcitonin, or numerical analysis of leukocyte (sub)-counts. Cytokines appear also not suited due to their short half-life and pleiotropy, their unexclusive origin from immune cells, and their potential to undergo antagonization by circulating inactivating molecules. Thus, beyond leukocyte quantification and use of routine biomarkers, direct assessment of immune cell function seems required to characterize the immune systems' status. This may include determination of, e.g., ex vivo cellular cytokine release, phagocytosis activity, and/or antigen-presenting capacity. In this regard, standardized flow-cytometric assessment of the major histocompatibility-II complex human leukocyte antigen (-D related) (HLA-DR) has gained particular interest. Monocytic HLA-DR (mHLA-DR) controls the interplay between innate and adaptive immunity and may serve as a "global" biomarker of injury-associated immunosuppression, and its decreased expression is associated with adverse clinical outcomes (e.g., secondary infection risk, mortality). Importantly, recent data demonstrate that injury-associated immunosuppression can be reversed-opening up new therapeutic avenues in affected patients. Here we discuss the potential scientific and clinical value of assessment of functional immunity with a focus on monocytes/macrophages and review the current state of knowledge and potential perspectives for affected critically ill patients.

C-reactive protein in the detection of post-stroke infections: systematic review and individual participant data analysis

We conducted a systematic review and individual participant data meta-analysis to explore the role of C-reactive protein (CRP) in early detection or prediction of post-stroke infections. CRP, an acute-phase reactant binds to the phosphocholine expressed on the surface of dead or dying cells and some bacteria, thereby activating complement and promoting phagocytosis by macrophages. We searched PubMed up to May-2015 for studies measuring CRP in stroke and evaluating post-stroke infections. Individual participants' data were merged into a single database. CRP levels were standardized and divided into quartiles. Factors independently associated with post-stroke infections were determined by logistic regression analysis and the additional predictive value of CRP was assessed by comparing areas under receiver operating characteristic curves and integrated discrimination improvement index. Data from seven studies including 699 patients were obtained. Standardized CRP levels were higher in patients with post-stroke infections beyond 24 h. Standardized CRP levels in the fourth quartile were independently associated with infection in two different logistic regression models, model 1 [stroke severity and dysphagia, odds ratio = 9.70 (3.10-30.41)] and model 2 [age, sex, and stroke severity, odds ratio = 3.21 (1.93-5.32)]. Addition of CRP improved discrimination in both models [integrated discrimination improvement = 9.83% (0.89-18.77) and 5.31% (2.83-7.79), respectively], but accuracy was only improved for model 1 (area under the curve 0.806-0.874, p = 0.036). In this study, CRP was independently associated with development of post-stroke infections, with the optimal time-window for measurement at 24-48 h. However, its additional predictive value is moderate over clinical information. Combination with other biomarkers in a panel seems a promising strategy for future studies.