Response of C-reactive protein and serum amyloid A to influenza A infection in older adults

Longitudinal Three-Year Associations of Dietary Fruit and Vegetable Intake with Serum hs-C-Reactive Protein in Adults with and without Type 1 Diabetes

High-sensitivity C-reactive protein (hs-CRP) is a widely used clinical biomarker of systemic inflammation, implicated in many chronic conditions, including type 1 diabetes (T1D). Despite the increasing emphasis on dietary intake as a modifiable risk factor for systemic inflammation, the association of hs-CRP with fruit and vegetable consumption is relatively underexplored in T1D. To address this gap, we investigated the longitudinal associations of dietary pattern-derived fruit and vegetable scores with hs-CRP in adults with and without T1D. Additionally, we examined the impact of berry consumption as a distinct food group. Data were collected in the Coronary Artery Calcification in Type 1 Diabetes study over two visits that were three years apart. At each visit, participants completed a food frequency questionnaire, and hs-CRP was measured using a particle-enhanced immunonephelometric assay. Mixed effect models were used to examine the three-year association of fruit and vegetable scores with hs-CRP. Adjusted models found a significant inverse association between blueberry intake and hs-CRP in the nondiabetic (non-DM) group. Dietary Approaches to Stop Hypertension- and Alternative Healthy Eating Index-derived vegetable scores were also inversely associated with hs-CRP in the non-DM group (all p-values ≤ 0.05). Conversely, no significant associations were observed in the T1D group. In conclusion, dietary pattern-derived vegetable scores are inversely associated with hs-CRP in non-DM adults. Nonetheless, in T1D, chronic hyperglycemia and related metabolic abnormalities may override the cardioprotective features of these food groups at habitually consumed servings.

Effect of influenza vaccination on resting metabolic rate and c-reactive protein concentrations in healthy young adults

OBJECTIVES

Chronic immune activation and severe inflammatory states are positively associated with resting metabolic rate (RMR; kcal/day), but the impacts of mild immune stimuli on metabolism are poorly understood. This study investigates the within-individual association between the inflammatory response to influenza vaccination and RMR in young adults.

METHODS

We evaluated RMRs through indirect calorimetry and circulating c-reactive protein (CRP) concentrations (mg/L)-a direct measure of inflammation-via high-sensitivity immunoassays of dried blood spots (n = 17) at baseline and two- and seven-days post-vaccine. Wilcoxon matched-pairs signed-rank tests were used to evaluate the magnitude of the CRP and RMR responses. Type II Wald chi-square tests of linear mixed-effect models assessed whether those responses were correlated.

RESULTS

Baseline CRP was 1.39 ± 1.26 mg/L. On day two post-vaccine, CRP increased by 1.47 ± 1.37 mg/L (p < 0.0001), representing a 106% increase above baseline values. CRP remained higher on day seven post-vaccine, 1.32 ± 2.47 mg/L (p = 0.05) above baseline values. There were no statistically significant changes in RMR from baseline to day two (p = 0.98) or day seven (p = 0.21). Change in CRP from baseline did not predict RMR variation across days (p = 0.46).

CONCLUSIONS

We find no evidence that adult influenza vaccination results in a corresponding increase in RMR. These results suggest that the energetic cost of an influenza vaccine's mild inflammatory stimulus is either too small to detect or is largely compensated by a temporary downregulation of energy allocated to other metabolic tasks.

Determinants of Influenza Vaccine Uptake in Patients With Cardiovascular Disease and Strategies for Improvement

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide. Influenza infection is associated with an increased risk of cardiovascular events (myocardial infarction, stroke, and heart failure exacerbation) and mortality, and all‐cause mortality in patients with CVD. Infection with influenza leads to a systemic inflammatory and thrombogenic response in the host body, which further causes destabilization of atherosclerotic plaques. Influenza vaccination has been shown to be protective against cardiovascular and cerebrovascular events in several observational and prospective studies of at‐risk populations. Hence, many international guidelines recommend influenza vaccination for adults of all ages, especially for individuals with high‐risk conditions such as CVD. Despite these long‐standing recommendations, influenza vaccine uptake among US adults with CVD remains suboptimal. Specifically, vaccination uptake is strikingly low among patients aged <65 years, non‐Hispanic Black individuals, those without health insurance, and those with diminished access to healthcare services. Behavioral factors such as perceived vaccine efficacy, vaccine safety, and attitudes towards vaccination play an important role in vaccine acceptance at the individual and community levels. With the ongoing COVID‐19 pandemic, there is a potential threat of a concurrent epidemic with influenza. This would be devastating for vulnerable populations such as adults with CVD, further stressing the need for ensuring adequate influenza vaccination coverage. In this review, we describe a variety of strategies to improve the uptake of influenza vaccination in patients with CVD through improved understanding of key sociodemographic determinants and behaviors that are associated with vaccination, or the lack thereof. We further discuss the potential use of relevant strategies for COVID‐19 vaccine uptake among those with CVD.

A novel case of impaired C-reactive protein response following open-heart surgery: A case report and review of the literature

BACKGROUND

C-reactive protein (CRP) is expected to increase in response to a range of inflammatory stimuli such as infections or extensive tissue trauma.

CASE REPORT

We present a novel case of severely impaired CRP response following NSTEMI, influenza A infection and open-heart surgery in which serum CRP concentrations remained < 1 mg/L during an observational period of 28 days.

CONCLUSION

To our knowledge, no previous publications exists describing patients with a lack of CRP response following cardiothoracic surgery. We believe this to be a novel finding warranting further investigations regarding the etiology and prevalence of this phenomenon.

Histone H4 potentiates neutrophil inflammatory responses to influenza A virus: Down-modulation by H4 binding to C-reactive protein and Surfactant protein D

Neutrophils participate in the early phase of the innate response to uncomplicated influenza A virus (IAV) infection but also are a major component in later stages of severe IAV or COVID 19 infection where neutrophil extracellular traps (NETs) and associated cell free histones are highly pro-inflammatory. It is likely that IAV interacts with histones during infection. We show that histone H4 binds to IAV and aggregates viral particles. In addition, histone H4 markedly potentiates IAV induced neutrophil respiratory burst responses. Prior studies have shown reactive oxidants to be detrimental during severe IAV infection. C reactive protein (CRP) and surfactant protein D (SP-D) rise during IAV infection. We now show that both of these innate immune proteins bind to histone H4 and significantly down regulate respiratory burst and other responses to histone H4. Isolated constructs composed only of the neck and carbohydrate recognition domain of SP-D also bind to histone H4 and partially limit neutrophil responses to it. These studies indicate that complexes formed of histones and IAV are a potent neutrophil activating stimulus. This finding could account for excess inflammation during IAV or other severe viral infections. The ability of CRP and SP-D to bind to histone H4 may be part of a protective response against excessive inflammation in vivo.

Effects of serum amyloid protein A on influenza A virus replication and viral interactions with neutrophils

Innate immunity is vital for the early control of influenza A virus (IAV) infection. Serum amyloid A (SAA1) is an acute phase reactant produced in the liver and lung that rises dramatically during IAV infection. The potential role of SAA1 in host defense against IAV is unknown. SAA1 has been reported to directly activate neutrophils and to recruit them to the lung during infectious and inflammatory processes. Neutrophils are the most abundant cell recruited to the lung in the early phase of IAV infection. There are different forms and preparations of SAA1 that have found to have different effects on phagocyte responses, through various receptors. In this paper, we test the direct effects of various preparations of serum derived or recombinant SAA on IAV and how it modulates the interactions of IAV with neutrophils. All SAA preparations bound to IAV in vitro but caused minimal hemagglutination inhibition or viral aggregation. The human serum‐derived SAA1 or the complex of SAA1 with HDL did have IAV neutralizing activity in vitro, whereas the recombinant SAA1 preparations did not. We found that different SAA preparations also had markedly different effects on neutrophil functions, with E. coli‐derived SAA1 triggering some responses in neutrophils on its own or in presence of IAV whereas mammalian cell‐derived SAA1 did not. This discrepancy could be explained by the reported contamination of the former preparation with bacterial components. Of interest, however, serum SAA alone, serum SAA complexed with HDL, or HDL alone potentiated some neutrophil responses to IAV. Our results suggest that SAA may play some role in host response to IAV, but further work needs to be done to clarify the role of different variants of SAA alone or complexed with HDL.

Types of acute phase reactants and their importance in vaccination

Vaccines are considered to be one of the most cost-effective life-saving interventions in human history. The body's inflammatory response to vaccines has both desired effects (immune response), undesired effects [(acute phase reactions (APRs)] and trade-offs. Trade-offs are more potent immune responses which may be potentially difficult to separate from potent acute phase reactions. Thus, studying acute phase proteins (APPs) during vaccination may aid our understanding of APRs and homeostatic changes which can result from inflammatory responses. Depending on the severity of the response in humans, these reactions can be classified as major, moderate or minor. In this review, types of APPs and their importance in vaccination will be discussed.

Outcomes of Acute Myocardial Infarction in Patients with Influenza and Other Viral Respiratory Infections

BACKGROUND

Acute influenza infection can trigger acute myocardial infarction, however, outcome of patients with acute myocardial infarction during influenza infection is largely unknown.

METHODS

Patients ≥18 years old with ST-elevation and non-ST-elevation myocardial infarction during January 2013-December 2014 were identified using the National Inpatient Sample. The clinical outcomes were compared among patients who had no respiratory infection to the ones with influenza and other viral respiratory infections using propensity score-matched analysis.

RESULTS

Of 1,884,985 admissions for acute myocardial infarction, acute influenza and other viral infections were diagnosed in 9,885 and 11,485 patients, respectively, accounting for 1.1% of patients. Acute myocardial infarction patients with concomitant influenza infection had a worse outcome than those with acute myocardial infarction alone, in terms of in-hospital case fatality rate, development of shock, acute respiratory failure, acute kidney injury, and higher rate of blood transfusion after propensity scores. The length of stay is also significantly longer in influenza patients with acute myocardial infarction, compared with patients with acute myocardial infarction alone. However, patients who developed acute myocardial infarction during other viral respiratory infection have a higher rate of acute respiratory failure but overall lower mortality rate, and are less likely to develop shock or require blood transfusion after propensity match. Despite presenting with acute myocardial infarction, less than one-fourth of patients with concomitant influenza infection underwent coronary angiography, but more than half (51.4%) required revascularization.

CONCLUSION

Influenza infection is associated with worse outcomes in acute myocardial infarction patients, and patients were less likely to receive further evaluation with invasive coronary angiography.

Serum amyloid A protein in the course of infectious mononucleosis

Background:

Serum amyloid A (SAA) protein is a major acute phase protein. Increased concentrations have been reported in many inflammatory diseases. In bacterial infections, high levels correlate with those of C-reactive protein (CRP). In viral infections, where CRP changes are weaker, SAA is of value for establishing early diagnosis, monitoring the severity, and the evolution of the disease.

Objective:

Evaluation of SAA as a marker for diagnosis of infectious mononucleosis, including severe forms.

Material and methods:

A total of 31 patients with non-complicated and severe, complicated infectious mononucleosis were examined. SAA and CRP were measured by immuniturbidimetric assays at the day of admission and 4.97 ± 1.35 days later.

Results:

SAA increases significantly than those in a control group, without correlation with the etiologic agent. It decreases when full recovery appears. In the subgroup of subjects with complications, we observed significant increased SAA when Epstein-Barr virus /EBV/ was the etiologic agent, in the course of bacterial and viral secondary infection. SAA is higher than CRP in non-complicated group. In cases of bacterial superinfections, both increase simultaneously and treatment have to be adapted. Second, serum sample for CRP is normal in patients without full recovery where SAA stay increased.

Conclusion:

In viral infections, high SAA concentrations are indicative for early diagnosis, severe course of the diseases, effect of the treatment, early recovery, and disease outcome. When SAA and CRP increase simultaneously, bacterial co-infection is suspected, and relevant antibiotic treatments have to be initiated.

Inflammatory and oxidative stress biomarkers in alkaptonuria: data from the DevelopAKUre project

OBJECTIVE

The aim of this work was to assess baseline serum levels of established biomarkers related to inflammation and oxidative stress in samples from alkaptonuric subjects enrolled in SONIA1 (n = 40) and SONIA2 (n = 138) clinical trials (DevelopAKUre project).

METHODS

Baseline serum levels of Serum Amyloid A (SAA), IL-6, IL-1β, TNFα, CRP, cathepsin D (CATD), IL-1ra, and MMP-3 were determined through commercial ELISA assays. Chitotriosidase activity was assessed through a fluorimetric method. Advanced Oxidation Protein Products (AOPP) were determined by spectrophotometry. Thiols, S-thiolated proteins and Protein Thiolation Index (PTI) were determined by spectrophotometry and HPLC. Patients' quality of life was assessed through validated questionnaires.

RESULTS

We found that SAA serum levels were significantly increased compared to reference threshold in 57.5% and 86% of SONIA1 and SONIA2 samples, respectively. Similarly, chitotriosidase activity was above the reference threshold in half of SONIA2 samples, whereas CRP levels were increased only in a minority of samples. CATD, IL-1β, IL-6, TNFα, MMP-3, AOPP, thiols, S-thiolated protein and PTI showed no statistically significant differences from control population. We provided evidence that alkaptonuric patients presenting with significantly higher SAA, chitotriosidase activity and PTI reported more often a decreased quality of life. This suggests that worsening of symptoms in alkaptonuria (AKU) is paralleled by increased inflammation and oxidative stress, which might play a role in disease progression.

CONCLUSIONS

Monitoring of SAA may be suggested in AKU to evaluate inflammation. Though further evidence is needed, SAA, chitotriosidase activity and PTI might be proposed as disease activity markers in AKU.

An Investigation of Extracellular Histones in Pig-To-Baboon Organ Xenotransplantation

BACKGROUND

Serum (extracellular) histone levels are increased in inflammatory states and in the presence of coagulation dysfunction, for example, trauma, chemical/ischemic injury, infection. There is increasing evidence of a systemic inflammatory response associated with the presence of a pig xenograft in a nonhuman primate. We evaluated extracellular histone levels in baboons with various pig xenografts.

METHODS

We measured serum histones in baboons with pig heterotopic heart (n = 8), life-supporting kidney (n = 5), orthotopic liver (n = 4), and artery patch (n = 9) grafts by enzyme-linked immunosorbent assay. C-reactive protein (CRP), free triiodothyronine (fT3), serum amyloid A (SAA), and platelet counts were also measured, all of which may provide an indication of an inflammatory state. We investigated the effect of histones on platelet aggregation and on cytotoxicity of pig cells in vitro.

RESULTS

Serum histones increased when baboons developed consumptive coagulopathy (eg, thrombocytopenia) or infection. CRP levels tended to be higher and fT3 levels lower when consumptive coagulopathy developed. Measurement of SAA correlated fairly well with CRP and indicated the state of inflammation. Treatment of the recipient with tocilizumab reduced the level of serum histones, CRP, and SAA, and increased the level of fT3 and platelet counts. In vitro, histone-induced platelet aggregation and endothelial cell apoptosis were both significantly reduced by the NF-κB pathway inhibitor, parthenolide.

CONCLUSIONS

These noninvasive assays may be useful for monitoring the health status of nonhuman primate recipients of pig organ grafts and may help in management after xenotransplantation. Tocilizumab and NF-κB inhibitors might prove valuable in reducing the inflammatory response to a pig xenograft.

Enriching Diet with n-3 PUFAs to Help Prevent Cardiovascular Diseases in Healthy Adults: Results from Clinical Trials

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are believed to be important for cardiovascular health. Many investigations have been carried out in an attempt to examine the effect of n-3 PUFAs intake, in the form of supplementation or fortified foods, for the management of cardiovascular disease (CVD) and risk factors for CVD, whereas less is known about the effect on healthy individuals. The present study reviews the available literature in order to examine the relationship between n-3 PUFAs intake, either via supplementation or enriched food, and the prevention of CVD among healthy adults. Interventional clinical trials on subjects aged >18 years old with none of the established risk factors for CVD have been considered for review. n-3 PUFAs supplementation or enriched food may positively regulate triglycerides and some lipoprotein subsets, as well as several vascular and coagulation parameters, even in healthy patients, presenting no risk factors for CVD, suggesting a protective effect. Diet enrichment with omega-3 is likely to be useful in helping to lower the risk of developing CVD in healthy individuals, but still offers no strong evidence of a tangible benefit on a population level. Additional studies are needed to determine the optimal daily intake, especially to prevent the unfavorable effects of PUFAs over-consumption.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Retrospective study of risk factors for mortality in human avian influenza A(H7N9) cases in Zhejiang Province, China, March 2013 to June 2014

BACKGROUND

The influenza A(H7N9) virus causes a serious disease that threatens human health. Fatalities associated with human infections caused by this virus are of great public health concern; however, the possible risk factors are not yet fully known.

METHODS

A stratified sampling method, incorporating household income levels and a random number table method, was used to select laboratory-confirmed A(H7N9) cases for this study. Eighty-five patients were selected randomly from 139 laboratory-confirmed A(H7N9) cases occurring in Zhejiang Province between March 1, 2013 and June 30, 2014. Data were collected using a standard method. To test the statistical significance among discrete variables, univariate analyses were used to compare two groups. The Kaplan-Meier product-limit method was used to analyze the patient survival fraction. The Cox proportional hazards regression model was used to analyze all variables with p ≤ 0.05 in the univariate analysis. Lastly, a stepwise procedure was used to construct a final model with a significance level of p > 0.10 for removal and p<0.05 for re-entry.

RESULTS

A total of 85 patients with H7N9 virus infection were identified. Among these, 30 (35.29%) died. In the univariate analysis, the following factors were associated with a high risk of influenza A(H7N9) case fatality: age ≥ 60 years (p=0.008), low education level (p=0.030), chronic diseases (p=0.029), poor hand hygiene (p=0.010), time from illness onset to the first medical visit (p=0.029) and to intensive care unit admission (p=0.008), an incubation period of ≤ 5 days (p=0.039), a peak C-reactive protein ≥ 120 mg/l (p=0.012), increased initial neutrophil count (p=0.020), decreased initial lymphocyte count (p=0.021), and initial infection of both lungs (p=0.003). Multivariate analysis confirmed that the independent predictors of H7N9 virus infection mortality in Zhejiang, China were hand hygiene (hazard ratio (HR) 5.163, 95% confidence interval (CI) 1.164-22.661), age (HR 1.042, 95% CI 1.007-1.076), and peak CRP (HR 1.009, 95% CI 1.002-1.016).

CONCLUSIONS

Improvements in immunity, early case identification and treatment, and personal protection measures are key to addressing the high human avian influenza A(H7N9) case fatality rate.

Effects of supplemental long-chain omega-3 fatty acids and erythrocyte membrane fatty acid content on circulating inflammatory markers in a randomized controlled trial of healthy adults

The long-chain omega-3 polyunsaturated (n-3 PUFA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), may have anti-inflammatory effects. We evaluated the dose-response effect of EPA+DHA supplementation on circulating TNF-α, IL-6, and CRP and explored associations between red blood cell (RBC) membrane PUFA content and TNF-α, IL-6, and CRP. Young adults with low fish intake (n=116) received one of five doses (0, 300, 600, 900, or 1,800 mg/d EPA+DHA) for 5 months. There were no significant effects of supplemental EPA+DHA on IL-6 or CRP; however, there was a marginal treatment effect for TNF-α (p<0.08). At baseline, higher quartiles of RBC DHA were associated with lower TNF-α (p=0.001); higher quartiles of arachidonic acid were associated with higher TNF-α (p=0.005). EPA+DHA supplementation had no dose-response effect on TNF-α, IL-6, or CRP in healthy young adults; however, associations between inflammatory markers and RBC PUFA warrant further investigation.

Plasma proteomic analysis of patients infected with H1N1 influenza virus

This study profiled the plasma proteins of patients infected by the 2011 H1N1 influenza virus. Differential protein expression was identified in plasma obtained from noninfected control subjects (n = 15) and H1N1-infected subjects (n = 15). Plasma proteins were separated by a 2DE large gel system and identified by nano-ultra performance LC-MS. Western blot assays were performed to validate proteins. Eight plasma proteins were upregulated and six proteins were downregulated among 3316 plasma proteins in the H1N1-infected group as compared with the control group. Of 14 up- and downregulated proteins, nine plasma proteins were validated by Western blot analysis. Putative protein FAM 157A, leucine-rich alpha 2 glycoprotein, serum amyloid A protein, and dual oxidase 1 showed significant differential expression. The identified plasma proteins could be potential candidates for biomarkers of H1N1 influenza viral infection. Further studies are needed to develop these proteins as diagnostic biomarkers.

Serum amyloid A and pairing formyl peptide receptor 2 are expressed in corneas and involved in inflammation-mediated neovascularization

AIM

To solidify the involvement of Saa-related pathway in corneal neovascularization (CorNV). The pathogenesis of inflammatory CorNV is not fully understood yet, and our previous study implicated that serum amyloid A (Saa) 1 (Saa1) and Saa3 were among the genes up-regulated upon CorNV induction in mice.

METHODS

Microarray data obtained during our profiling project on CorNV were analyzed for the genes encoding the four SAA family members (Saa1-4), six reported SAA receptors (formyl peptide receptor 2, Tlr2, Tlr4, Cd36, Scarb1, P2rx7) and seven matrix metallopeptidases (Mmp) 1a, 1b, 2, 3, 9, 10, 13 reportedly to be expressed upon SAA pathway activation. The baseline expression or changes of interested genes were further confirmed in animals with CorNV using molecular or histological methods. CorNV was induced in Balb/c and C57BL/6 mice by placing either three interrupted 10-0 sutures or a 2 mm filter paper soaked with sodium hydroxide in the central area of the cornea. At desired time points, the corneas were harvested for histology examination or for extraction of mRNA and protein. The mRNA levels of Saa1, Saa3, Fpr2, Mmp2 and Mmp3 in corneas were detected using quantitative reverse transcription-PCR, and SAA3 protein in tissues detected using immunohistochemistry or western blotting.

RESULTS

Microarray data analysis revealed that Saa1, Saa3, Fpr2, Mmp2, Mmp3 messengers were readily detected in normal corneas and significantly up-regulated upon CorNV induction. The changes of these five genes were confirmed with real-time PCR assay. On the contrary, other SAA members (Saa2, Saa4), other SAA receptors (Tlr2, Tlr4, Cd36, P2rx7, etc), or other Mmps (Mmp1a, Mmp1b, Mmp9, Mmp10, Mmp13) did not show consistent changes. Immunohistochemistry study and western blotting further confirmed the expression of SAA3 products in normal corneas as well as their up-regulation in corneas with CorNV.

CONCLUSION

SAA-FPR2 pathway composing genes were expressed in normal murine corneas and, upon inflammatory stimuli challenge to the corneas, their expressions were up-regulated, suggesting their roles in pathogenesis of CorNV. The potential usefulness of SAA-FPR2 targets in future management of CorNV-related diseases deserves investigation.

Correlation of C-reactive protein to severity of symptoms in acute influenza A infection

Background:

Currently there is no objective measure to determine disease severity in patients with acute influenza infection. During acute viral infections, C-reactive protein (CRP) has been shown to be elevated.

Aim:

To study the relationship between the symptoms of acute influenza A infection and correlate them with the level of inflammation as measured by serum CRP levels.

Settings and Design:

Prospective study.

Materials and Methods:

We enrolled a convenience sample of adults presenting to an urban academic emergency department (ED), who had positive Enzyme-linked immunosorbent assay detection of the influenza A antigen. The subjects were excluded if they had immunosuppression, liver disease or were currently taking antiviral medication. A previously validated severity of symptom (SOS) score was calculated by asking the participants to record the severity of seven symptoms associated with influenza infection. The subjects had the serum C-reactive protein (CRP) levels tested during their ED visit.

Statistical Analysis:

A linear regression model was used with CRP as a predictor of the SOS score. Pearson's product-moment coefficient was used to measure the dependence between the two quantities.

Results:

Thirty-two subjects were enrolled from January through March 2009, and of those, eight patients were excluded from the analysis, leaving 24 study subjects: 58% were women, of ages 18 to 63 years, with a mean age of 31 years (95% CI 25, 37). The mean SOS score was 14.1 ranging from 6 to 21 (95% CI 12.6, 26.4). The mean CRP score was 24.6 ranging from 0 to 64.7 (95% CI 15.8, 33.4). The correlation coefficient between the SOS score and CRP levels was r = 0.65 (P=0.00056).

Conclusion:

The severity of symptoms associated with acute influenza A infection correlateswith the serum CRP levels.

Evaluation of lymphocyte levels in a random sample of 218 elderly individuals from São Paulo city

Background

Age-associated changes in the immune system cause decreased protection after vaccination and increased rates of infections and tumor development.

Methods

Lymphocyte percentages were compared by gender and age to establish differences between subtypes. Three mL blood samples were obtained from 218 randomly selected individuals (60-101 years old) who live in São Paulo city. Blood was lysed with Tris phosphate buffer and stained for 30 minutes with monoclonal antibodies (CD3PerCP, CD4FITC, CD8Pe, CD19Pe) for analysis by flow cytometry. Statistical analysis was by ANOVA.

Results

The percentage of CD4⁺ T cells (p-value = 0.005) and the CD4/CD8 ratio (p-value = 0.010) were lower in men, whereas the percentage of CD8⁺ T cells was lower (p-value = 0.002) in women; the percentage of B cells (CD19⁺ ) was similar between groups. Individuals grouped by gender and age range and compared showed a drop in CD4⁺ cells in 75 to 79-year-old men (female: 46.1% ± 8.1% and male: 38.8% ± 10.5%; p-value = 0.023). Also, the 80 to 84-year-old group of men had a higher percentage of CD8⁺ (female: 20.8% ± 8.2%, and male: 27.2% ± 8.2%; p-value = 0.032). Low percentages of B cells were detected in men in the 75 to 79-year-old (p-value = 0.003), 85 to 89-year-old (p-value = 0.020) and older than 90 year old (p-value = 0.002) age ranges.

Conclusion

Elderly men present with more changes in lymphocyte subsets compared to elderly women. These findings could demonstrate impairment in the immune response since the lower CD4⁺ in men would provide less help to B cells (also lower in men) in terms of antibody production. In addition, the increase in CD8⁺ cells in this group could represent chronic inflammation observed during the aging process.

Ageing: a risk factor for amyloid A amyloidosis in rheumatoid arthritis

OBJECTIVE

Acceleration of amyloid A (AA) amyloidosis induction by ageing has not been extensively studied in rheumatoid arthritis (RA). The aim of this study is to clarify contribution of ageing to the development of AA amyloidosis associated with RA in our large cohort.

METHODS

388 adult-onset RA patients whose RA was complicated by biopsy-proven AA amyloidosis were enrolled. The ages of RA onset and AA amyloidosis diagnosis were estimated in each patient. The contributions of ageing, inflammatory activity, SAA1 exon 3 polymorphism as well as gender to the pathogenesis of AA amyloidosis in 144 cases were also studied by multiple regression analysis.

RESULTS

Subjects with RA onset at older age had a shorter period to develop amyloidosis than those with disease onset at younger age (p < 0.001). The interval between RA onset and AA amyloidosis diagnosis was significantly shorter in the SAA1.3 positive group than in the SAA1.3 negative (p=0.001). Multiple regression analysis indicated that the interval from RA onset to diagnosis of AA amyloidosis is determined by age at RA onset (p < 0.001), the most recent median annual CRP concentration (p=0.006) and SAA1.3 allele (p=0.058). Gender did not significantly contribute to the onset of AA amyloidosis (p=0.569).

CONCLUSION

Ageing is an independent risk factor for the induction of AA amyloidosis complicating RA.

Transcription analysis on response of swine lung to H1N1 swine influenza virus

BACKGROUND

As a mild, highly contagious, respiratory disease, swine influenza always damages the innate immune systems, and increases susceptibility to secondary infections which results in considerable morbidity and mortality in pigs. Nevertheless, the systematical host response of pigs to swine influenza virus infection remains largely unknown. To explore it, a time-course gene expression profiling was performed for comprehensive analysis of the global host response induced by H1N1 swine influenza virus in pigs.

RESULTS

At the early stage of H1N1 swine virus infection, pigs were suffering mild respiratory symptoms and pathological changes. A total of 268 porcine genes showing differential expression (DE) after inoculation were identified to compare with the controls on day 3 post infection (PID) (Fold change ≥ 2, p < 0.05). The DE genes were involved in many vital functional classes, mainly including signal transduction, immune response, inflammatory response, cell adhesion and cell-cell signalling. Noticeably, the genes associated with immune and inflammatory response showed highly overexpressed. Through the pathway analysis, the significant pathways mainly concerned with Cell adhesion molecules, Cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway and MAPK signaling pathway, suggesting that the host took different strategies to activate these pathways so as to prevent virus infections at the early stage. However, on PID 7, the predominant function classes of DE genes included signal transduction, metabolism, transcription, development and transport. Furthermore, the most significant pathways switched to PPAR signaling pathway and complement and coagulation cascades, showing that the host might start to repair excessive tissue damage by anti-inflammatory functions. These results on PID 7 demonstrated beneficial turnover for host to prevent excessive inflammatory damage and recover the normal state by activating these clusters of genes.

CONCLUSIONS

This study shows how the target organ responds to H1N1 swine influenza virus infection in pigs. The observed gene expression profile could help to screen the potential host agents for reducing the prevalence of swine influenza virus and further understand the molecular pathogenesis associated with H1N1 infection in pigs.

Cytokines and acute phase proteins associated with acute swine influenza infection in pigs

This study set out to investigate the cytokines and acute phase proteins (APPs) associated with the acute stages of experimentally-induced swine influenza virus (SIV) infection in 3-week-old, colostrum-deprived, caesarean-derived piglets. The piglets were inoculated intratracheally with 10(7.5) 50% egg infective dose [EID(50)] Swine/Belgium/1/98 (H1N1) SIV and were euthanased at time-points between 0 and 120h post-inoculation (PI). Broncho-alveolar lavage fluid (BALF), lung homogenates and sera were examined for inflammatory mediators by bioassay or ELISA. Interferon (IFN)-α, interleukin (IL)-6, IL-1 and tumour necrosis factor (TNF)-α peaked in BALF 24-30h PI, when virus titres and the severity of clinical signs were maximal. Whereas IFN-γ and IL-12, but not IL-18, increased in tandem in BALF, serum cytokine concentrations were either undetectable or were up to 100-fold lower. The APP C-reactive protein (CRP) and haptoglobin peaked 24h later than the cytokines and reached higher levels in serum than in BALF. In contrast, lipopolysaccharide (LPS)-binding protein (LBP) only increased in BALF. Lung virus titres tightly correlated with BALF IFN-α, IL-6, IL-1, TNF-α, IFN-γ and IL-12, as well as with serum IL-6, IFN-α and IFN-γ. Signs of disease correlated with the same cytokines in BALF and serum, as well as with BALF LBP and serum CRP. The findings suggest that IFN-γ and IL-12 play a role in the pathogenesis of SIV and that APPs are induced by cytokines. This influenza infection model may have value in assessing the therapeutic potential of cytokine antagonists.

Workshop on immunizations in older adults: identifying future research agendas

Goals for immunization in older adults may differ from those in young adults and children, in whom complete prevention of disease is the objective. Often, reduced hospitalization and death but also averting exacerbation of underlying chronic illness, functional decline, and frailty are important goals in the older age group. Because of the effect of age on dendritic cell function, T cell-mediated immune suppression, reduced proliferative capacity of T cells, and other immune responses, the efficacy of vaccines often wanes with advanced age. This article summarizes the discussion and proceedings of a workshop organized by the Association of Specialty Professors, the Infectious Diseases Society of America, the American Geriatrics Society, the National Institute on Aging, and the National Institute of Allergy and Infectious Diseases. Leading researchers and clinicians in the fields of immunology, epidemiology, infectious diseases, geriatrics, and gerontology reviewed the current status of vaccines in older adults, identified knowledge gaps, and suggest priority areas for future research. The goal of the workshop was to identify what is known about immunizations (efficacy, effect, and current schedule) in older adults and to recommend priorities for future research. Investigation in the areas identified has the potential to enhance understanding of the immune process in aging individuals, inform vaccine development, and lead to more-effective strategies to reduce the risk of vaccine-preventable illness in older adults.

Identifying viral infections in vaccinated Chronic Obstructive Pulmonary Disease (COPD) patients using clinical features and inflammatory markers

Background  Known inflammatory markers have limited sensitivity and specificity to differentiate viral respiratory tract infections from other causes of acute exacerbation of COPD (AECOPD). To overcome this, we developed a multi‐factorial prediction model combining viral symptoms with inflammatory markers.

Methods  Interleukin‐6 (IL‐6), serum amyloid A (SAA) and viral symptoms were measured in stable COPD and at AECOPD onset and compared with the viral detection rates on multiplex PCR. The predictive accuracy of each measure was assessed using logistic regression and receiver operating characteristics curve (ROC) analysis.

Results  There was a total of 33 viruses detected at the onset of 148 AECOPD, the majority 26 (79%) were picornavirus. Viral symptoms with the highest predictive values were rhinorrhoea [Odds ratio (OR) 4·52; 95% CI 1·99–10·29; P < 0·001] and sore throat (OR 2·64; 95% CI 1·14–6·08; P = 0·022), combined the AUC ROC curve was 0·67. At AECOPD onset patients experienced a 1·6‐fold increase in IL‐6 (P = 0·008) and 4·5‐fold increase in SAA (P < 0·001). The addition of IL‐6 to the above model significantly improved diagnostic accuracy compared with symptoms alone (AUC ROC 0·80 (P = 0·012).

Conclusion  The addition of inflammatory markers increases the specificity of a clinical case definition for viral infection, particularly picornavirus infection.

Inflammation in aging part 1: physiology and immunological mechanisms

During the aging process, remodeling of several body systems occurs, and these changes can have a startling effect upon the immune system. The reduction in sex steroids and growth hormones and declines in vitamin D concentration that accompany the aging process are associated with increases in the baseline levels of inflammatory proteins. At the same time, inflammation arising from atherosclerosis and other chronic diseases further contributes to the inflammatory milieu and effects a state of chronic inflammation. This chronic inflammation, or ''inflammaging'' as it has been termed, seems to be associated with a host of adverse effects contributing to many of the health problems that increase morbidity and decrease both quality of life and the ability to maintain independence in old age. For nurses to be truly informed when caring for older people and to ensure that they have a detailed understanding of the complexities of older people's health needs, they must have a knowledge of the physiological and immunological changes with age. This is the first of a two-part article on inflammatory processes in aging. These age-related changes are presented here, including an examination of the impact of genetic and lifestyle factors. The effect of these changes on the health of the individual and implications for practice are described in Part 2.

Systems-based candidate genes for human response to influenza infection

Influenza A is a serious respiratory illness that can be debilitating and may cause complications leading to hospitalization and death. The outcome of infection with the influenza A virus is determined by a complex interplay of viral and host factors. With the ongoing threat of seasonal influenza and the potential emergence of new, more virulent strains of influenza viruses, we need to develop a better understanding of genetic variation in the human population and its association with severe outcomes from influenza infection. We propose a list of approximately 100 systems-based candidate genes for future study of the genetic basis of influenza disease and immunity in humans, based on evidence in the published literature for their potential role in the pathogenesis of this infection: binding of the virus to receptors on the host cell surface; cleavability of HA by host proteases; virus replication in host cells; destruction of host cells by apoptosis; state of immunocompetence of the individual host; and viral infections predisposing to bacterial infection.

Toll-like receptor 2 expression level on monocytes in patients with viral infections: monitoring infection severity

For viral infectious diseases, reliable biomarkers capable of monitoring recovery and therapeutic effects and that simultaneously discriminate between viral and bacterial infection are necessary. In this study, by using flow-cytometric quantification system, Toll-like receptor 2 (TLR2) expression levels on monocytes of influenza patients (n=47) were compared with those of healthy volunteers (n=50). Subsequently, throughout their acute, convalescent and healed phases, TLR2, C-reactive protein (CRP), serum amyroid A (SAA), and neopterin levels were followed. Additionally, TLR2 levels in other viral infectious diseases were assayed. The results showed that TLR2 level in influenza patients was remarkably up-regulated in acute phase compared to healthy volunteers (p<0.001). Thereafter, TLR2 levels normalized in good accordance with their recovery processes. CRP and neopterin levels were relatively widely distributed from normal to abnormally high levels in acute phase in spite of similar disease severity among the patients. SAA levels did not necessarily reflect the patients' clinical course during their recovery. Clinical observations of other viral infections also indicated that TLR2 levels were compatible with infection severity. TLR2 expression level on monocytes might serve as a unique biomarker useful in viral infectious diseases.

Serum amyloid a is a biomarker of acute exacerbations of chronic obstructive pulmonary disease

RATIONALE

Much of the total disease burden and cost of chronic obstructive pulmonary disease (COPD) is associated with acute exacerbations of COPD (AECOPD). Serum amyloid A (SAA) is a novel candidate exacerbation biomarker identified by proteomic screening.

OBJECTIVES

To assess SAA as a biomarker of AECOPD.

METHODS

Biomarkers were assessed (1) cross-sectionally (stable vs. AECOPD; 62 individuals) and (2) longitudinally with repeated measures (baseline vs. AECOPD vs. convalescence; 78 episodes in 37 individuals). Event severity was graded (I, ambulatory; II, hospitalized; III, respiratory failure) based on consensus guidelines.

MEASUREMENTS AND MAIN RESULTS

Presumptively newly acquired pathogens were associated with onset of symptomatic AECOPD. In the cross-sectional study, both SAA and C-reactive protein (CRP) were elevated at AECOPD onset compared with stable disease (SAA median, 7.7 vs. 57.6 mg/L; P < 0.01; CRP median, 4.6 vs. 12.5 mg/L; P < 0.01). Receiver operator characteristics analysis was used to generate area-under-curve values for event severity. SAA discriminated level II/III events (SAA, 0.88; 95% confidence interval, 0.80-0.94 vs. CRP, 0.80; 95% confidence interval, 0.70-0.87; P = 0.05). Combining SAA or CRP with major symptoms (Anthonisen criteria, dyspnea) did not further improve the prediction model for severe episodes. IL-6 and procalcitonin were not informative.

CONCLUSIONS

SAA is a novel blood biomarker of AECOPD that is more sensitive than CRP alone or in combination with dyspnea. SAA may offer new insights into the pathogenesis of AECOPD.

Impact of influenza vaccination on major cause-specific mortality

The efficacy of influenza vaccination is not well understood for major cause-specific mortality except pneumonia. For 10 months we followed the mortality data of 35,637 vaccinated elderly (>65 years old) in a county with 102,698 elderly in southern Taiwan. A multivariate Cox model showed that vaccination was significantly associated with lower mortality for all causes, [hazards ratio (HR)=0.56], stroke (HR=0.35), renal disease (HR=0.40), diabetes mellitus (HR=0.45), pneumonia (HR=0.47), COPD (HR=0.55), malignancy (HR=0.74), and heart diseases (HR=0.78), p<0.05. Influenza vaccination was strongly associated with reducing major cause-specific mortality.

Inflammatory response after influenza vaccination in men with and without carotid artery disease

OBJECTIVE

Inflammatory markers are associated with vascular disease; however, variation in the acute phase response (APR) has not been evaluated. We evaluated whether the APR magnitude in men with severe carotid artery disease (CAAD) (>80% stenosis) differed from that of men without stenosis (<15% stenosis).

METHODS AND RESULTS

White males with (n=43) and without (n=61) severe CAAD receiving clinical influenza vaccinations were recruited. Their baseline and 24-hour after -vaccination blood samples were assayed for C-reactive protein (CRP), IL-6, and serum amyloid-a (SAA). In vivo APR to vaccination was measurable and varied among subjects. Adjusted for age, smoking, oral hypoglycemics, aspirin, and stain use, the relative 24-hour changes in levels of ln(CRP), ln(IL-6), and ln(SAA) were higher in men with CAAD than in men without, but only the SAA response was significant (P=0.02); the relative SAA response was 1.6 (95% confidence interval, 1.1 to 2.5) times higher in men with than without CAAD. The APR for all markers appeared to be independent of baseline levels.

CONCLUSIONS

Influenza vaccination results in a mild, but measurable, APR in men with and without CAAD. SAA APR variability may be a predictor of severe vascular disease that is independent of basal SAA level.

Reducing major cause-specific hospitalization rates and shortening hospital stays after influenza vaccination

BACKGROUND

The impact of influenza vaccination on major cause-specific hospitalization and the duration of hospital stay is rarely reported. Our purpose was to study the effect of vaccine efficacy on major disease-specific hospitalization and the duration of hospital stays among elderly persons.

SUBJECTS AND METHODS

From 1 January through 30 June 2001, we prospectively observed 35,637 vaccinated elderly persons (age, >or=65 years) and 53,094 unvaccinated elderly persons in Kaohsiung County, Taiwan, by computerized linkage to the National Health Insurance database. Of these persons, 21,347 had been assigned a high-risk status by the Department of Health, Taiwan. Univariate and multivariate logistic regression were used for determining vaccine efficacy in hospitalization. Multiple linear regression analyses were performed for determining the length of hospital stays.

RESULTS

In both high-risk and low-risk groups, vaccination was associated with reducing the rates of hospitalization for all causes (20% vs. 23%), lung diseases, congestive heart failure (43% vs. 32%), renal disease, and liver disease (P<.05). It was also significant for stroke, hypertension, diabetes, neoplasm, and injury in low-risk patients (P<.05). Multivariate logistic regression showed that vaccination was significantly associated with reducing the rate of hospitalization (odds ratio [OR], 0.89; 95% confidence interval [CI], 0.86-0.92), but those with high-risk status had an increased risk of hospitalization (OR, 3.69; 95% CI, 3.56-3.82). Multiple linear regression analysis showed that vaccination decreased the duration of all-cause hospital stays (coefficient, -2.4 days; 95% CI, -2.7 to -2.1 days) and of hospitalization due to lung disease (coefficient, -4.9 days; 95% CI, -6.0 to -3.8 days).

CONCLUSION

Influenza vaccination may reduce hospitalization rates and shorten hospital stays not only for lung diseases but also for other common diseases in high-risk and low-risk elderly populations.

Influenza infection exerts prominent inflammatory and thrombotic effects on the atherosclerotic plaques of apolipoprotein E-deficient mice

BACKGROUND

The role of infection in the development and complications of atherosclerosis has been the focus of much attention. We reported previously that influenza vaccination was associated with reduced risk of recurrent myocardial infarction. Here, we report the effect of influenza A virus on the apolipoprotein E-deficient (apoE(-/-)) mouse, an animal model of atherosclerosis.

METHODS AND RESULTS

Twenty-four apoE(-/-) mice >24 months old were injected with 1 LD(50) (lethal dose 50) of influenza A virus. Ten wild-type C57BL/6 infected mice and 11 noninfected age-matched apoE(-/-) mice served as controls. Multiple aortic sections were studied histologically 3, 5, and 10 days later. The infected mice showed markedly increased intimal cellularity compared with the noninfected apoE(-/-) mice. No aortic abnormalities were seen in infected wild-type mice. Ten infected apoE(-/-) mice had a significant subendothelial infiltrate composed of a heterogeneous group of cells that stained positively for smooth muscle cell actin, F4/80 (macrophages), and CD3 (T lymphocytes). One case of subocclusive platelet and fibrin-rich thrombus was seen.

CONCLUSIONS

This study shows that influenza infection promotes inflammation, smooth muscle cell proliferation, and fibrin deposition in atherosclerotic plaques.

hsCRP and HDL effects of statins trial (CHEST): rapid effect of statin therapy on C-reactive protein and high-density lipoprotein levels A clinical investigation

Inflammation contributes to the pathogenesis of coronary heart disease and elevated serum levels of C-reactive protein (CRP) are independently associated with increased coronary risk. This study assessed whether there were differences in the effects on CRP and high-density lipoprotein (HDL) cholesterol levels among patients treated with three common statins. In a prospective, observational study, 80 dyslipidemic adults without evidence of cardiovascular disease were treated with 10 mg atorvastatin (A), 20 mg simvastatin (S), or 40 mg pravastatin (P) daily. CRP and lipid profiles were assayed before and after 12 weeks of therapy; in 21 patients, CRP levels were also measured after 1 and 4 weeks. The three treatment groups experienced comparable reductions in CRP (A: 33%, S: 42%, and P: 30%) and statistically insignificant changes in HDL cholesterol levels. CRP began to decrease after 1 week of treatment, and decreased further at 4 and 12 weeks of therapy. The change in the log-transformed CRP concentration correlated with the change in the log-transformed LDL cholesterol concentration. Subjects had similar baseline CRP levels, lipid profiles, and coronary risk factors. The authors conclude that at doses achieving similar reductions in LDL cholesterol, the three statins were associated with comparable decreases in CRP without significant changes in HDL cholesterol levels. The correlation between the reductions in CRP and LDL cholesterol differs from the findings of other published studies, and should prompt further investigation of the mechanism by which statins reduce CRP.