NFκB and NLRP3/NLRC4 inflammasomes regulate differentiation, activation and functional properties of monocytes in response to distinct SARS-CoV-2 proteins

Increased recruitment of transitional and non-classical monocytes in the lung during SARS-CoV-2 infection is associated with COVID-19 severity. However, whether specific innate sensors mediate the activation or differentiation of monocytes in response to different SARS-CoV-2 proteins remain poorly characterized. Here, we show that SARS-CoV-2 Spike 1 but not nucleoprotein induce differentiation of monocytes into transitional or non-classical subsets from both peripheral blood and COVID-19 bronchoalveolar lavage samples in a NFκB-dependent manner, but this process does not require inflammasome activation. However, NLRP3 and NLRC4 differentially regulated CD86 expression in monocytes in response to Spike 1 and Nucleoprotein, respectively. Moreover, monocytes exposed to Spike 1 induce significantly higher proportions of Th1 and Th17 CD4 + T cells. In contrast, monocytes exposed to Nucleoprotein reduce the degranulation of CD8 + T cells from severe COVID-19 patients. Our study provides insights in the differential impact of innate sensors in regulating monocytes in response to different SARS-CoV-2 proteins, which might be useful to better understand COVID-19 immunopathology and identify therapeutic targets.

The role of bronchoscopy in patients with SARS-CoV-2 pneumonia

Background

The role of bronchoscopy in coronavirus disease 2019 (COVID-19) is a matter of debate.

Patients and methods

This observational multicentre study aimed to analyse the prognostic impact of bronchoscopic findings in a consecutive cohort of patients with suspected or confirmed COVID-19. Patients were enrolled at 17 hospitals from February to June 2020. Predictors of in-hospital mortality were assessed by multivariate logistic regression.

Results

A total of 1027 bronchoscopies were performed in 515 patients (age 61.5±11.2 years; 73% men), stratified into a clinical suspicion cohort (n=30) and a COVID-19 confirmed cohort (n=485). In the clinical suspicion cohort, the diagnostic yield was 36.7%. In the COVID-19 confirmed cohort, bronchoscopies were predominantly performed in the intensive care unit (n=961; 96.4%) and major indications were: difficult mechanical ventilation (43.7%), mucus plugs (39%) and persistence of radiological infiltrates (23.4%). 147 bronchoscopies were performed to rule out superinfection, and diagnostic yield was 42.9%. There were abnormalities in 91.6% of bronchoscopies, the most frequent being mucus secretions (82.4%), haematic secretions (17.7%), mucus plugs (17.6%), and diffuse mucosal hyperaemia (11.4%). The independent predictors of in-hospital mortality were: older age (OR 1.06; p<0.001), mucus plugs as indication for bronchoscopy (OR 1.60; p=0.041), absence of mucosal hyperaemia (OR 0.49; p=0.041) and the presence of haematic secretions (OR 1.79; p=0.032).

Conclusion

Bronchoscopy may be indicated in carefully selected patients with COVID-19 to rule out superinfection and solve complications related to mechanical ventilation. The presence of haematic secretions in the distal bronchial tract may be considered a poor prognostic feature in COVID-19.

Bronchoscopy is part of the armamentarium against #COVID19. It allows diagnosis, facilitates mechanical ventilation and provides prognostic information. This information could be used to refine healthcare pathways in order to improve outcomes.https://bit.ly/2QuAQOt

Challenges in understanding host genetics and severity of community-acquired pneumonia

A heritable predisposition to early death due to infection was observed three decades ago [1]. Apart from exciting discoveries in the field of primary immunodeficiencies, genetic variants predisposing to severe infection and outcome at a population level remain largely elusive [2, 3]. Genetic association studies on sepsis were largely based on a candidate gene approach. In 2015, Rautanenet al. [4] reported the first genome-wide association study (GWAS) in sepsis. A meta-analysis of three independent cohorts of critically ill patients with sepsis recruited in numerous centres from Europe, Canada, United States, Australia, New Zealand and South Africa was performed. They reported that the C allele of the single-nucleotide variant (SNV) rs4957796 at the FER gene was associated with a protective additive effect in 28-day survival only in patients with pneumonia, but not in those with other causes of sepsis. Schönewecket al. [5] did not replicate the findings Rautanenet al. [4] in a mixed cohort of patients of European ancestry with severe sepsis admitted at German intensive care units (ICUs). However, their study was underpowered for mortality. Hinzet al.[6], in a cohort of white patients with acute respiratory distress syndrome (ARDS) due to pneumonia from a single Centre in Germany, found that the rs4957796 TT genotype was associated with a higher 90-day mortality exclusively in the small subgroup of patients with severe ARDS.

This study found no association of the top two associated FER variants with severity of community-acquired pneumonia. Precise characterisation of phenotypes may be required in order to unravel the genetic mechanisms predisposing to poor outcome in sepsis.https://bit.ly/3jc9SmR

Should MASP-2 Deficiency Be Considered a Primary Immunodeficiency? Relevance of the Lectin Pathway

Mannose-binding lectin (MBL)-associated serine protease-2 (MASP-2) is an indispensable enzyme for the activation of the lectin pathway of complement. Its deficiency is classified as a primary immunodeficiency associated to pyogenic bacterial infections, inflammatory lung disease, and autoimmunity. In Europeans, MASP-2 deficiency, due to homozygosity for c.359A > G (p.D120G), occurs in 7 to 14/10,000 individuals. We analyzed the presence of the p.D120G mutation in adults (increasing the sample size of our previous studies) and children. Different groups of patients (1495 adults hospitalized with community-acquired pneumonia, 186 adults with systemic lupus erythematosus, 103 pediatric patients with invasive pneumococcal disease) and control individuals (1119 healthy adult volunteers, 520 adult patients without history of relevant infectious diseases, and a pediatric control group of 311 individuals) were studied. Besides our previously reported MASP-2-deficient healthy adults, we found a new p.D120G homozygous individual from the pediatric control group. We also reviewed p.D120G homozygous individuals reported so far: a total of eleven patients with a highly heterogeneous range of disorders and nine healthy controls (including our four MASP-2-deficient individuals) have been identified by chance in association studies. Individuals with complete deficiencies of several pattern recognition molecules of the lectin pathway (MBL, collectin-10 and collectin-11, and ficolin-3) as well as of MASP-1 and MASP-3 have also been reviewed. Cumulative evidence suggests that MASP-2, and even other components of the LP, are largely redundant in human defenses and that individuals with MASP-2 deficiency do not seem to be particularly prone to infectious or autoimmune diseases.

Early and Late Cardiovascular Events in Patients Hospitalized for Community-Acquired Pneumonia

INTRODUCTION

Community-acquired pneumonia increases the risk of cardiovascular events (CVE). The objective of this study was to analyze host, severity, and etiology factors associated with the appearance of early and late events and their impact on mortality.

METHOD

Prospective multicenter cohort study in patients hospitalized for pneumonia. CVE and mortality rates were collected at admission, 30-day follow-up (early events), and one-year follow-up (late events).

RESULTS

In total, 202 of 1,967 (10.42%) patients presented early CVE and 122 (6.64%) late events; 16% of 1-year mortality was attributed to cardiovascular disease. The host risk factors related to cardiovascular complications were: age ≥65 years, smoking, and chronic heart disease. Alcohol abuse was a risk factor for early events, whereas obesity, hypertension, and chronic renal failure were related to late events. Severe sepsis and Pneumonia Severity Index (PSI) ≥3 were independent risk factors for early events, and only PSI ≥3 for late events. Streptococcus pneumoniae was the microorganism associated with most cardiovascular complications. Developing CVE was an independent factor related to early (OR 2.37) and late mortality (OR 4.05).

CONCLUSIONS

Age, smoking, chronic heart disease, initial severity, and S. pneumoniae infection are risk factors for early and late events, complications that have been related with an increase of the mortality risk during and after the pneumonia episode. Awareness of these factors can help us make active and early diagnoses of CVE in hospitalized CAP patients and design future interventional studies to reduce cardiovascular risk.

Neutrophil Count Percentage and Neutrophil-Lymphocyte Ratio as Prognostic Markers in Patients Hospitalized for Community-Acquired Pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is a common serious infection. This study aimed to evaluate the prognostic utility of neutrophil count percentage (NCP) and neutrophil-lymphocyte ratio (NLR) in patients with CAP.

METHODS

Retrospective study of hospitalized patients with CAP. Patients had a blood test at admission and 3-5 days after hospitalization (early-stage test). The main outcome variables were 30-day and 90-day mortality.

RESULTS

Two hundred and 9patients were included. Patients who survived had significant reductions in both NCP and NLR between admission and the day 3-5 blood tests (from 85.8% to 65.4% for NCP and from 10.1 to 3.2 for NLR). Twenty-five patients died in the first 90 days. Patients who died had lower, non-significant reductions in NCP (from 84.8% to 74%) and NLR (from 9.9 to 6.9) and significantly higher early-stage NCP and NLR than those who survived. NCP values higher than 85% and NLR values higher than 10 in the early-stage blood test were associated with a higher risk of mortality, even after multivariate adjustment (HR for NCP: 12; HR for NLR: 6.5).

CONCLUSION

NCP and NLR are simple, low-cost parameters with prognostic utility, especially when measured 3-5 days after CAP diagnosis. High NLR and/or NCP levels are associated with a greater risk of mortality at 90 days.

Clinical impact of chronic obstructive pulmonary disease on non-cystic fibrosis bronchiectasis. A study on 1,790 patients from the Spanish Bronchiectasis Historical Registry

Background

Few studies have evaluated the coexistence of bronchiectasis (BE) and chronic obstructive pulmonary disease (COPD) in series of patients diagnosed primarily with BE. The aim of this study was to analyse the characteristics of patients with BE associated with COPD included in the Spanish Bronchiectasis Historical Registry and compare them to the remaining patients with non-cystic fibrosis BE.

Methods

We conducted a multicentre observational study of historical cohorts, analysing the characteristics of 1,790 patients who had been included in the registry between 2002 and 2011. Of these, 158 (8.8%) were registered as BE related to COPD and were compared to the remaining patients with BE of other aetiologies.

Results

Patients with COPD were mostly male, older, had a poorer respiratory function and more frequent exacerbations. There were no differences in the proportion of patients with chronic bronchial colonisation or in the isolated microorganisms. A significantly larger proportion of patients with COPD received treatment with bronchodilators, inhaled steroids and intravenous antibiotics, but there was no difference in the use of long term oral or inhaled antibiotherapy. During a follow-up period of 3.36 years, the overall proportion of deaths was 13.8%. When compared to the remaining aetiologies, patients with BE associated with COPD presented the highest mortality rate. The multivariate analysis showed that the diagnosis of COPD in a patient with BE as a primary diagnosis increased the risk of death by 1.77.

Conclusion

Patients with BE related to COPD have the same microbiological characteristics as patients with BE due to other aetiologies. They receive treatment with long term oral and inhaled antibiotics aimed at controlling chronic bronchial colonisation, even though the current COPD treatment guidelines do not envisage this type of therapy. These patients’ mortality is notably higher than that of remaining patients with non-cystic fibrosis BE.

Glycosaminoglycans are involved in bacterial adherence to lung cells

Background

Lower respiratory infections are among the top ten causes of death worldwide. Since pathogen to cell adhesion is a crucial step in the infection progress, blocking the interaction between eukaryotic receptors and bacterial ligands may enable the pathogenesis process to be stopped. Cell surface glycosaminoglycans (GAGs) are known to be mediators in the adhesion of diverse bacteria to different cell types, making it of interest to examine their involvement in the attachment of various pathogenic bacteria to lung cells, including epithelial cells and fibroblasts.

Methods

The function of cell surface GAGs in bacterial adhesion was studied by reducing their levels through inhibiting their biosynthesis and enzymatic degradation, as well as in binding competition experiments with various species of GAGs. The participation of the different bacterial adhesins in attachment was evaluated through competition with two peptides, both containing consensus heparin binding sequences. Blocking inhibition assays using anti-syndecans and the enzymatic removal of glypicans were conducted to test their involvement in bacterial adhesion. The importance of the fine structure of GAGs in the interaction with pathogens was investigated in competition experiments with specifically desulfated heparins.

Results

The binding of all bacteria tested decreased when GAG levels in cell surface of both lung cells were diminished. Competition experiments with different types of GAGs showed that heparan sulfate chains are the main species involved. Blocking or removal of cell surface proteoglycans evidenced that syndecans play a more important role than glypicans. The binding was partially inhibited by peptides including heparin binding sequences. Desulfated heparins also reduced bacterial adhesion to different extents depending on the bacterium and the sulfated residue, especially in fibroblast cells.

Conclusions

Taken together, these data demonstrate that the GAG chains of the cell surface are involved in the adhesion of bacterial adhesins to lung cells. Heparan sulfate seems to be the main species implicated, and binding is dependent on the sulfation pattern of the molecule. These data could facilitate the development of new anti-infective strategies, enabling the development of new procedures for blocking the interaction between pathogens and lung cells more effectively.

Sex bias in diagnostic delay in bronchiectasis: An analysis of the Spanish Historical Registry of Bronchiectasis

Diagnostic delay is common in most respiratory diseases, particularly in bronchiectasis. However, sex bias in diagnostic delay has not been studied to date. Objective: Assessment of diagnostic delay in bronchiectasis by sex. Methods: The Spanish Historical Registry of Bronchiectasis recruited adults diagnosed with bronchiectasis from 2002 to 2011 in 36 centres in Spain. From a total of 2113 patients registered we studied 2099, of whom 1125 (53.6%) were women. Results: No differences were found for sex or age (61.0 ± 20.6, p = 0.88) or for localization of bronchiectasis (p = 0.31). Bronchiectasis of unknown aetiology and secondary to asthma, childhood infections and tuberculosis was more common in women (all ps < 0.05). More men than women were chronic obstructive pulmonary disease-related bronchiectasis and colonized by Haemophilus influenzae (p < 0.001 for both). Onset of symptoms was earlier in women. The diagnostic delay for women with bronchiectasis was 2.1 years more than for men (p = 0.001). Discussion: We recorded a substantial delay in the diagnosis of bronchiectasis. This delay was significantly longer in women than in men (>2 years). Independent factors associated with this sex bias were age at onset of symptoms, smoking history, daily expectoration and reduced lung function.

Inflammation biomarkers in blood as mortality predictors in community-acquired pneumonia admitted patients: Importance of comparison with neutrophil count percentage or neutrophil-lymphocyte ratio

Introduction

The increase and persistence of inflammation in community-acquired pneumonia (CAP) patients can lead to higher mortality. Biomarkers capable of measuring this inadequate inflammatory response are likely candidates to be related with a bad outcome. We investigated the association between concentrations of several inflammatory markers and mortality of CAP patients.

Material and methods

This was a prospective study of hospitalised CAP patients in a Spanish university hospital. Blood tests upon admittance and in the early-stage evolution (72–120 hours) were carried out, where C-reactive protein, procalcitonin, proadrenomedullin, copeptin, white blood cell, Lymphocyte Count Percentage (LCP), Neutrophil Count Percentage (NCP) and Neutrophil/Lymphocyte Ratio (NLR) were measured. The outcome variable was mortality at 30 and 90 days. Statistical analysis included logistic regression, ROC analysis and area-under-curve test.

Results

154 hospitalised CAP patients were included. Patients who died during follow-up had higher levels of procalcitonin, copeptin, proadrenomedullin, lower levels of LCP, and higher of NCP and NLR. Remarkably, multivariate analysis showed a relationship between NCP and mortality, regardless of age, severity of CAP and comorbidities. AUC analysis showed that NLR and NCP at admittance and during early-stage evolution achieved a good diagnostic power. ROC test for NCP and NLR were similar to those of the novel serum biomarkers analysed.

Conclusions

NLR and NCP, are promising candidate predictors of mortality for hospitalised CAP patients, and both are cheaper, easier to perform, and at least as reliable as the new serum biomarkers. Future implementation of new biomarkers would require comparison not only with classic inflammatory parameters like White Blood Cell count but also with NLR and NCP.

Etiology of Bronchiectasis in a Cohort of 2047 Patients. An Analysis of the Spanish Historical Bronchiectasis Registry

INTRODUCTION

Bronchiectasis is caused by many diseases. Establishing its etiology is important for clinical and prognostic reasons. The aim of this study was to evaluate the etiology of bronchiectasis in a large patient sample and its possible relationship with demographic, clinical or severity factors, and to analyze differences between idiopathic disease, post-infectious disease, and disease caused by other factors.

METHODS

Multicenter, cross-sectional study of the SEPAR Spanish Historical Registry (RHEBQ-SEPAR). Adult patients with bronchiectasis followed by pulmonologists were included prospectively. Etiological studies were based on guidelines and standardized diagnostic tests included in the register, which were later included in the SEPAR guidelines on bronchiectasis.

RESULTS

A total of 2,047 patients from 36 Spanish hospitals were analyzed. Mean age was 64.9years and 54.9% were women. Etiology was identified in 75.8% of cases (post-Infection: 30%; cystic fibrosis: 12.5%; immunodeficiencies: 9.4%; COPD: 7.8%; asthma: 5.4%; ciliary dyskinesia: 2.9%, and systemic diseases: 1.4%). The different etiologies presented different demographic, clinical, and microbiological factors. Post-infectious bronchiectasis and bronchiectasis caused by COPD and asthma were associated with an increased risk of poorer lung function. Patients with post-infectious bronchiectasis were older and were diagnosed later. Idiopathic bronchiectasis was more common in female non-smokers and was associated with better lung function, a higher body mass index, and a lower rate of Pseudomonas aeruginosa than bronchiectasis of known etiology.

CONCLUSIONS

The etiology of bronchiectasis was identified in a large proportion of patients included in the RHEBQ-SEPAR registry. Different phenotypes associated with different causes could be identified.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

IFITM3 and severe influenza virus infection. No evidence of genetic association

Influenza virus infection (IVI) is typically subclinical or causes a self-limiting upper respiratory disease. However, in a small subset of patients IVI rapidly progresses to primary viral pneumonia (PVP) with respiratory failure; a minority of patients require intensive care unit admission. Inherited and acquired variability in host immune responses may influence susceptibility and outcome of IVI. However, the molecular basis of such human factors remains largely elusive. It has been proposed that homozygosity for IFITM3 rs12252-C is associated with a population-attributable risk of 5.4 % for severe IVI in Northern Europeans and 54.3 % for severe H1N1pdm infection in Chinese. A total of 148 patients with confirmed IVI were considered for recruitment; 118 Spanish patients (60 of them hospitalized with PVP) and 246 healthy Spanish individuals were finally included in the statistical analysis. PCR-RFLP was used with confirmation by Sanger sequencing. The allele frequency for rs12252-C was found to be 3.5 % among the general Spanish population. We found no rs12252-C homozygous individuals in our control group. The only Spanish patient homozygous for rs12252-C had a neurological disorder (a known risk factor for severe IVI) and mild influenza. Our data do not suggest a role of rs12252-C in the development of severe IVI in our population. These data may be relevant to recognize whether patients homozygous for rs12252-C are at risk of severe influenza, and hence require individualized measures in the case of IVI.

Predictors of Severe Sepsis among Patients Hospitalized for Community-Acquired Pneumonia

Background

Severe sepsis, may be present on hospital arrival in approximately one-third of patients with community-acquired pneumonia (CAP).

Objective

To determine the host characteristics and micro-organisms associated with severe sepsis in patients hospitalized with CAP.

Results

We performed a prospective multicenter cohort study in 13 Spanish hospital, on 4070 hospitalized CAP patients, 1529 of whom (37.6%) presented with severe sepsis. Severe sepsis CAP was independently associated with older age (>65 years), alcohol abuse (OR, 1.31; 95% CI, 1.07–1.61), chronic obstructive pulmonary disease (COPD) (OR, 1.75; 95% CI, 1.50–2.04) and renal disease (OR, 1.57; 95% CI, 1.21–2.03), whereas prior antibiotic treatment was a protective factor (OR, 0.62; 95% CI, 0.52–0.73). Bacteremia (OR, 1.37; 95% CI, 1.05–1.79), S pneumoniae (OR, 1.59; 95% CI, 1.31–1.95) and mixed microbial etiology (OR, 1.65; 95% CI, 1.10–2.49) were associated with severe sepsis CAP.

Conclusions

CAP patients with COPD, renal disease and alcohol abuse, as well as those with CAP due to S pneumonia or mixed micro-organisms are more likely to present to the hospital with severe sepsis.

Review of Non-Bacterial Infections in Respiratory Medicine: Viral Pneumonia

Although bacteria are the main pathogens involved in community-acquired pneumonia, a significant number of community-acquired pneumonia are caused by viruses, either directly or as part of a co-infection. The clinical picture of these different pneumonias can be very similar, but viral infection is more common in the pediatric and geriatric populations, leukocytes are not generally elevated, fever is variable, and upper respiratory tract symptoms often occur; procalcitonin levels are not generally affected. For years, the diagnosis of viral pneumonia was based on cell culture and antigen detection, but since the introduction of polymerase chain reaction techniques in the clinical setting, identification of these pathogens has increased and new microorganisms such as human bocavirus have been discovered. In general, influenza virus type A and syncytial respiratory virus are still the main pathogens involved in this entity. However, in recent years, outbreaks of deadly coronavirus and zoonotic influenza virus have demonstrated the need for constant alert in the face of new emerging pathogens. Neuraminidase inhibitors for viral pneumonia have been shown to reduce transmission in cases of exposure and to improve the clinical progress of patients in intensive care; their use in common infections is not recommended. Ribavirin has been used in children with syncytial respiratory virus, and in immunosuppressed subjects. Apart from these drugs, no antiviral has been shown to be effective. Prevention with anti-influenza virus vaccination and with monoclonal antibodies, in the case of syncytial respiratory virus, may reduce the incidence of pneumonia.

Review of Non-Bacterial Infections in Respiratory Medicine: Viral Pneumonia

Although bacteria are the main pathogens involved in community-acquired pneumonia, a significant number of community-acquired pneumonia are caused by viruses, either directly or as part of a co-infection. The clinical picture of these different pneumonias can be very similar, but viral infection is more common in the pediatric and geriatric populations, leukocytes are not generally elevated, fever is variable, and upper respiratory tract symptoms often occur; procalcitonin levels are not generally affected. For years, the diagnosis of viral pneumonia was based on cell culture and antigen detection, but since the introduction of polymerase chain reaction techniques in the clinical setting, identification of these pathogens has increased and new microorganisms such as human bocavirus have been discovered. In general, influenza virus type A and syncytial respiratory virus are still the main pathogens involved in this entity. However, in recent years, outbreaks of deadly coronavirus and zoonotic influenza virus have demonstrated the need for constant alert in the face of new emerging pathogens. Neuraminidase inhibitors for viral pneumonia have been shown to reduce transmission in cases of exposure and to improve the clinical progress of patients in intensive care; their use in common infections is not recommended. Ribavirin has been used in children with syncytial respiratory virus, and in immunosuppressed subjects. Apart from these drugs, no antiviral has been shown to be effective. Prevention with anti-influenza virus vaccination and with monoclonal antibodies, in the case of syncytial respiratory virus, may reduce the incidence of pneumonia.

The incidence of cardiovascular events after hospitalization due to CAP and their association with different inflammatory markers

Background

Late prognosis of Community-Acquired Pneumonia (CAP) patients is related to cardiovascular events. Persistence of inflammation-related markers, defined by high circulatory levels of interleukin 6 and 10 (IL-6/IL-10), is associated with a higher post-event mortality rate for CAP patients. However, association between these markers and other components of the immune response, and the risk of cardiovascular events, has not been adequately explored. The main objectives of this study are: 1) to quantify the incidence of cardiovascular disease, in the year post-dating their hospital admittance due to CAP and, 2) to describe the distribution patterns of a wide spectrum of inflammatory markers upon admittance to and release from hospital, and to determine their relationship with the incidence of cardiovascular disease.

Methods/design

A cohort prospective study. All patients diagnosed and hospitalized with CAP will be candidates for inclusion. The study will take place in the Universitary Hospital La Princesa, Spain, during two years. Two samples of blood will be taken from each patient: the first upon admittance and the second one prior to release, in order to analyse various immune agents. The main determinants are: pro-adrenomedullin, copeptin, IL-1, IL-6, TNF-α, IL-17, IFN-γ, IL-10 and TGF-β, E-Selectin, ICAM-1, VCAM-1 and subpopulations of peripheral T lymphocytes (T regulator, Th1 and Th17), together with other clinical and analytical variables. Follow up will start at admittance and finish a year after discharge, registering incidence of death and cardiovascular events. The main objective is to establish the predictive power of different inflammatory markers in the prognosis of CAP, in the short and long term, and their relationship with cardiovascular disease.

Discussion

The level of some inflammatory markers (IL-6/IL-10) has been proposed as a means to differentiate the degree of severity of CAP, but their association with cardiovascular risk is not well established. In this study we aim to define new inflammatory markers associated with cardiovascular disease that could be helpful for the prognosis of CAP patients, by describing the distribution of a wide spectrum of inflammatory mediators and analyzing their association with the incidence of cardiovascular disease and mortality one year after release from hospital.

Surfactant protein A genetic variants associate with severe respiratory insufficiency in pandemic influenza A virus infection

Introduction

Inherited variability in host immune responses influences susceptibility and outcome of Influenza A virus (IAV) infection, but these factors remain largely unknown. Components of the innate immune response may be crucial in the first days of the infection. The collectins surfactant protein (SP)-A1, -A2, and -D and mannose-binding lectin (MBL) neutralize IAV infectivity, although only SP-A2 can establish an efficient neutralization of poorly glycosylated pandemic IAV strains.

Methods

We studied the role of polymorphic variants at the genes of MBL (MBL2), SP-A1 (SFTPA1), SP-A2 (SFTPA2), and SP-D (SFTPD) in 93 patients with H1N1 pandemic 2009 (H1N1pdm) infection.

Results

Multivariate analysis showed that two frequent SFTPA2 missense alleles (rs1965708-C and rs1059046-A) and the SFTPA2 haplotype 1A⁰ were associated with a need for mechanical ventilation, acute respiratory failure, and acute respiratory distress syndrome. The SFTPA2 haplotype 1A¹ was a protective variant. Kaplan-Meier analysis and Cox regression also showed that diplotypes not containing the 1A¹ haplotype were associated with a significantly shorter time to ICU admission in hospitalized patients. In addition, rs1965708-C (P = 0.0007), rs1059046-A (P = 0.0007), and haplotype 1A⁰ (P = 0.0004) were associated, in a dose-dependent fashion, with lower PaO₂/FiO₂ ratio, whereas haplotype 1A¹ was associated with a higher PaO₂/FiO₂ ratio (P = 0.001).

Conclusions

Our data suggest an effect of genetic variants of SFTPA2 on the severity of H1N1pdm infection and could pave the way for a potential treatment with haplotype-specific (1A¹) SP-A2 for future IAV pandemics.

Influence of genetic variability at the surfactant proteins A and D in community-acquired pneumonia: a prospective, observational, genetic study

INTRODUCTION

Genetic variability of the pulmonary surfactant proteins A and D may affect clearance of microorganisms and the extent of the inflammatory response. The genes of these collectins (SFTPA1, SFTPA2 and SFTPD) are located in a cluster at 10q21-24. The objective of this study was to evaluate the existence of linkage disequilibrium (LD) among these genes, and the association of variability at these genes with susceptibility and outcome of community-acquired pneumonia (CAP). We also studied the effect of genetic variability on SP-D serum levels.

METHODS

Seven non-synonymous polymorphisms of SFTPA1, SFTPA2 and SFTPD were analyzed. For susceptibility, 682 CAP patients and 769 controls were studied in a case-control study. Severity and outcome were evaluated in a prospective study. Haplotypes were inferred and LD was characterized. SP-D serum levels were measured in healthy controls.

RESULTS

The SFTPD aa11-C allele was significantly associated with lower SP-D serum levels, in a dose-dependent manner. We observed the existence of LD among the studied genes. Haplotypes SFTPA1 6A(2) (P = 0.0009, odds ration (OR) = 0.78), SFTPA(2) 1A(0) (P = 0.002, OR = 0.79), SFTPA1-SFTPA2 6A2-1A(0) (P = 0.0005, OR = 0.77), and SFTPD-SFTPA1-SFTPA(2)C-6A2-1A(0) (P = 0.00001, OR = 0.62) were underrepresented in patients, whereas haplotypes SFTPA2 1A(10) (P = 0.00007, OR = 6.58) and SFTPA1-SFTPA2 6A(3)-1A (P = 0.0007, OR = 3.92) were overrepresented. Similar results were observed in CAP due to pneumococcus, though no significant differences were now observed after Bonferroni corrections. 1A(10) and 6A-1A were associated with higher 28-day and 90-day mortality, and with multi-organ dysfunction syndrome (MODS) and acute respiratory distress syndrome (ARDS) respectively. SFTPD aa11-C allele was associated with development of MODS and ARDS.

CONCLUSIONS

Our study indicates that missense single nucleotide polymorphisms and haplotypes of SFTPA1, SFTPA2 and SFTPD are associated with susceptibility to CAP, and that several haplotypes also influence severity and outcome of CAP.

Mannose-binding lectin and mannose-binding lectin-associated serine protease 2 in susceptibility, severity, and outcome of pneumonia in adults

BACKGROUND

Community-acquired pneumonia (CAP) is the leading cause of death from infection in developed countries. Mannose-binding lectin (MBL) and MBL-associated serine protease 2 (MASP-2) deficiencies are common primary immunodeficiencies the clinical penetrance of which remains controversial. MBL is a serum lectin that mediates phagocytosis and activates the lectin pathway of complement involving MASP-2.

OBJECTIVE

We sought to evaluate the significance of MBL deficiency (O/O genotypes) and insufficiency (O/O plus XA/O genotypes), as well as MASP-2 deficiency (D105G mutation), in the susceptibility to and severity and outcome of CAP in adults.

METHODS

MBL and MASP-2 serum levels, as well as lectin pathway activity with regard to MBL2 and MASP2 genotypes, were measured in healthy control subjects. For susceptibility, 848 patients with CAP, 1447 healthy control subjects, and a control group of 519 patients without relevant infectious diseases were studied in a case-control study. Severity and outcome were evaluated in a prospective study of the 848 patients.

RESULTS

We found similar frequencies of MBL2 and MASP2 alleles and genotypes among patients and control subjects. However, in a multivariate analysis MBL insufficiency was associated with the development of the most severe forms of sepsis (P = .007), acute respiratory failure (P = .009), multiorgan dysfunction syndrome (P = .036), intensive care unit admission (P = .020), and death (P = .003).

CONCLUSION

Our large study suggests that MBL plays a redundant role in human defenses against primary infection, at least in adults with CAP, and provides, for the first time, evidence that MBL insufficiency predisposes to higher severity and fatal outcome in patients with CAP, irrespective of the causal microorganisms.

Pneumococcal antimicrobial resistance: therapeutic strategy and management in community-acquired pneumonia

Streptococcus pneumoniae has been consistently shown to represent the most frequent causative agent of community-acquired pneumonia (CAP) and pneumococcal antibiotic resistance towards different families of antibiotics continues to be a much-debated issue. Microbial resistance causes a great deal of confusion in choosing an empirical treatment for pneumonia and this makes it necessary to know which factors actually determine the real impact of antimicrobial resistance on the outcome of pneumococcal infections. Several different aspects have to be taken into account when analyzing this matter, such as the study design, the condition of the patient at the time of diagnosis, the choice of the initial antimicrobial regimen (combination or monotherapy) and the pharmacokinetic/pharmacodynamic variables of the chosen antibiotic. It is generally accepted that in the treatment of beta-lactam-resistant pneumococcal infections, the use of standard antipneumococcal beta-lactam agents is unlikely to impact negatively on the outcome of CAP when appropriate agents are given in sufficient doses. As a general rule, for infections with penicillin-sensitive strains, penicillin or an aminopenicillin in a standard dosage will be effective; in the cases of strains with intermediate resistance, beta-lactam agents are still considered appropriate treatment although higher dosages are recommended; finally, infections with isolates of high-level penicillin resistance should be treated with alternative agents such as the third-generation cephalosporins or the new antipneumococcal fluoroquinolones. In areas of high prevalence of high-level macrolide resistance, empirical monotherapy with a macrolide is not optimal for the treatment of hospitalised patients with moderate or moderately-severe CAP. Fluoroquinolones are considered to be excellent antibiotics in the treatment of pneumococcal CAP in adults, but their general recommendation has been withheld due to fears of a widespread development of resistance. Most international guidelines recommend combination therapy (beta-lactam plus a macrolide) for the treatment of hospitalised patients with CAP.

Impact of initial antibiotic choice on mortality from pneumococcal pneumonia

To determine the impact of initial antimicrobial choice on 30-day mortality rate in patients with community-acquired pneumonia due to Streptococcus pneumoniae (CAP-SP), a prospective, observational study was conducted in 35 Spanish hospitals. A total of 638 patients with CAP-SP were identified. Antimicrobials were chosen by the attending physician. Patients were grouped into the following categories: beta-lactam monotherapy (n = 251), macrolide monotherapy (n = 37), beta-lactam plus macrolide (n = 198), levofloxacin alone/combination (n = 48), and other combinations (n = 104). The reference category was beta-lactam+macrolide. The 30-day survival probability was 84.9%. Using multivariate survival analysis, factors related to mortality in the entire population were: bilateral disease, suspected aspiration, shock, HIV infection, renal failure and pneumonia severity index (PSI) score Class IV versus I-III and categories V versus I-III. The association of beta-lactams+macrolides was not better than the use of beta-lactams alone. The current authors analysed the different groups of patients with significant mortality/morbidity: intensive care unit, PSI Class >III, renal failure, chronic lung disease and bacteraemia. Only in patients with PSI Class >III, who had undergone initial antimicrobial choice classified as other combinations, were associated with higher mortality. In conclusion, the current authors have not demonstrated an independent association between initial antimicrobial regimen and 30-day mortality in community-acquired pneumococcal pneumonia patients, except for those with a higher pneumonia severity index score.

Drug‐Resistant Pneumococcal Pneumonia: Clinical Relevance and Related Factors

A multicenter study of 638 cases of community-acquired pneumonia due to Streptococcus pneumoniae (SP-CAP) was performed to assess current levels of resistance. Of the pneumococcal strains, 35.7% had an minimum inhibitory concentration (MIC) of penicillin of > or =0.12 microg/mL (3 isolates had an MIC of 4 microg/mL), 23.8% had an MIC of erythromycin of 128 microg/mL, and 22.2% were multidrug resistant. Logistic regression determined that chronic pulmonary disease (odds ratio [OR], 1.44], human immunodeficiency virus infection (OR, 1.98), clinically suspected aspiration (OR, 2.12), and previous hospital admission (OR, 1.69) were related to decreased susceptibility to penicillin, and previous admission (OR, 1.89) and an MIC of penicillin of MIC > or =0.12 microg/mL (OR, 15.85) were related to erythromycin resistance (MIC, > or =1 microg/mL). The overall mortality rate was 14.4%. Disseminated intravascular coagulation, empyema, and bacteremia were significantly more frequent among patients with penicillin-susceptible SP-CAP. Among isolates with MICs of penicillin of > or =0.12 microg/mL, serotype 19 was predominant and was associated with a higher mortality rate. In summary, the rate of resistance to beta -lactams and macrolides among S. pneumoniae that cause CAP remains high, but such resistance does not result in increased morbidity.

Bronchoalveolar lavage in smokers: quantification of alveolar macrophages and neutrophils as markers of bronchial obstruction

Increased concentrations of neutrophils and alveolar macrophages are recovered in the bronchoalveolar lavage (BAL) of smokers compared with non-smokers. We designed a study to determine the relationship between neutrophils and alveolar macrophages recovered by BAL and the degree of air-flow obstruction, measured by spirometry (chronic air-flow obstruction was defined as: FEV1 < 80% of predicted and FEV1/FVC ratio < 70% of predicted) in healthy smokers. We found a significant correlation between spirometric values and the number of neutrophils and alveolar macrophages in BAL fluid obtained from healthy smokers. Our findings suggest that counts of 13-15x1000 neutrophils/ml and/or 430-450x1000 alveolar macrophages/ml in BAL fluid could be used as markers of air-flow obstruction in smokers.