Dietary Fiber Confers Protection against Flu by Shaping Ly6c- Patrolling Monocyte Hematopoiesis and CD8+ T Cell Metabolism.

Dietary fiber protects against chronic inflammatory diseases by dampening immune responses through short-chain fatty acids (SCFAs). Here we examined the effect of dietary fiber in viral infection, where the anti-inflammatory properties of SCFAs in principle could prevent protective immunity. Instead, we found that fermentable dietary fiber increased survival of influenza-infected mice through two complementary mechanisms. High-fiber diet (HFD)-fed mice exhibited altered bone marrow hematopoiesis, characterized by enhanced generation of Ly6c- patrolling monocytes, which led to increased numbers of alternatively activated macrophages with a limited capacity to produce the chemokine CXCL1 in the airways. Blunted CXCL1 production reduced neutrophil recruitment to the airways, thus limiting tissue immunopathology during infection. In parallel, diet-derived SCFAs boosted CD8+ T cell effector function by enhancing cellular metabolism. Hence, dietary fermentable fiber and SCFAs set an immune equilibrium, balancing innate and adaptive immunity so as to promote the resolution of influenza infection while preventing immune-associated pathology.

Associations of Depressive and Anxiety Disorders with Pulmonary Disorders in the Community: The PneumoLaus and PsyCoLaus Studies.

INTRODUCTION: Mental health disorders figure among the many comorbidities of obstructive respiratory diseases. The multisystemic characteristics of chronic respiratory disease and its impact on quality of life could affect depressive and/or anxiety disorders. We aimed to evaluate the association of spirometric indices, ventilatory disorders, and self-reported respiratory diseases with psychiatric disorders considering potential confounders. METHODS: We analysed data from CoLaus|PsyCoLaus, a Swiss population-based cohort study, consisting of 2'774 participants (56% women; mean age: 62.3 (standard deviation = ±9.9) years) who performed spirometry and completed semi-structured psychiatric interviews. We defined ventilatory disorders using GLI-2012 references. Major depressive episode (MDE) and anxiety disorders were defined using the DSM-IV (Diagnostic and Statistical Manual). RESULTS: 630 subjects (22.7%) presented a recent MDE. Reversible obstructive ventilatory disorders were associated with recent MDE (OR = 1.94, 95% confidence interval (95% CI) 1.10-3.43) and recent anxiety disorders (2.21 [1.16-4.22]) only in unadjusted model. Self-reported chronic obstructive pulmonary (COPD) and asthma were associated with MDE with ORs of 2.49 (95% CI, 1.19-5.27) and 1.56 (95% CI, 1.04-2.35) after adjustment, respectively. Possible restrictive ventilatory impairment was positively associated with recent anxiety disorders (OR = 2.46, 1.10-5.51). Z-scores of FEV1, FVC, and maximal mid-expiratory flow were not associated with psychiatric disorders. There was no association between ventilatory disorders and MDE in adjusted models. CONCLUSIONS: In this cross-sectional population-based study, the association between respiratory disorders and depressive disorders was observed for self-reported COPD and asthma, but not with objective diagnoses based on spirometry. Lung volumes are not associated with psychiatric disorders. Further prospective studies will be necessary to understand the significance of the association.

Microbiome-induced antigen-presenting cell recruitment coordinates skin and lung allergic inflammation.

BACKGROUND: Allergic skin inflammation often presents in early childhood; however, little is known about the events leading to its initiation and whether it is transient or long-term in nature. OBJECTIVE: We sought to determine the immunologic rules that govern skin inflammation in early life. METHODS: Neonatal and adult mice were epicutaneously sensitized with allergen followed by airway allergen challenge. Epicutaneous application of labeled allergen allowed for determination of antigen uptake and processing by antigen-presenting cells. RNAseq and microbiome analysis was performed on skin from neonatal and adult specific pathogen-free and germ-free mice. RESULTS: A mixed TH2/TH17 inflammatory response in the skin and the lungs of adult mice was observed following sensitization and challenge. Comparatively, neonatal mice did not develop overt skin inflammation, but exhibited systemic release of IL-17a and a TH2-dominated lung response. Mechanical skin barrier disruption was not sufficient to drive allergic skin inflammation, although it did promote systemic immune priming. Skin of neonatal mice and adult germ-free mice was seeded with low numbers of antigen-presenting cells and impaired chemokine and alarmin production. Enhanced chemokine and alarmin production, and seeding of the skin with antigen-presenting cells capable of instructing recruited cells to elicit their effector function, was, at least in part, dependent on formation of the microbiome, and consequently contributed to the development of overt skin disease. CONCLUSIONS: These data shed light on the principles that underlie allergic inflammation in different tissues and highlight a window of opportunity that might exist for early-life prevention of allergic diseases.

Swiss Recommendations for the Follow-Up and Treatment of Pulmonary Long COVID.

INTRODUCTION: Emerging evidence suggests that long-term pulmonary symptoms and functional impairment occurs in a proportion of individuals following SARS-CoV-2 infection. Although the proportion of affected patients remains to be determined, physicians are increasingly being confronted with patients reporting respiratory symptoms and impairment beyond the acute phase of COVID-19. In face of limited evidence, the Swiss Society for Pulmonology established a working group to address this area of unmet need and formulated diagnostic and treatment recommendations for the care of patients with pulmonary long COVID (LC). METHOD: The Swiss COVID Lung Study group and Swiss Society for Pulmonology (SSP) formulated 13 questions addressing the diagnosis and treatment of pulmonary LC. A survey within the SSP special interest groups involved in care of LC patients was conducted in Switzerland. A CORE process/Delphi-like process was used to formulate recommendations. Forty experienced pulmonologists replied to the first survey and 22 completed the second follow-up survey. Agreement of ≥70% consensus led to formulation of a recommendation. RESULTS: The participants in the survey reached consensus and formulated a strong recommendation for regarding the following points. Patients hospitalized for COVID-19 should have a pulmonary assessment including pulmonary function tests. Symptomatic subjects affected by COVID-19, including those with mild disease, should benefit from a pulmonary follow-up. Persistent respiratory symptoms after COVID-19 should be investigated by a pulmonary follow-up including plethysmography, diffusion capacity measurement, and blood gases analysis. Individuals having suffered from COVID-19 and who present with persistent respiratory symptoms should be offered a rehabilitation. Additional questions were given moderateor weak recommendations for. The panel did not reach sufficient consensus for pharmacological therapy (e.g., therapy specifically targeting lung fibrosis) to formulate recommendations for LC drug treatment. CONCLUSION: The formulated recommendations should serve as an interim guidance to facilitate diagnosis and treatment of patients with pulmonary LC. As new evidence emerges, these recommendations may need to be adapted.

Immunotherapy-Induced Airway Disease: A New Pattern of Lung Toxicity of Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICIs) have been shown to improve overall and progression-free survival in various cancers but have been associated with various immune-related adverse events (IRAEs), including interstitial lung disease, especially organizing pneumonia. We report 2 cases of isolated severe airway disease attributable to ICIs, a rarely reported pattern of lung toxicity. The first patient received nivolumab with or without ipilimumab in a randomized double-blind trial for locoregional metastatic melanoma. The second patient was treated with nivolumab for lung adenocarcinoma. An IRAE was suspected in both cases due to a temporal relationship between ICI initiation and symptom onset. ICIs were stopped, and high-dose prednisone, inhaled corticosteroids, and bronchodilators were administered, allowing a rapid clinical and functional improvement in Patient 1. In Patient 2, despite prolonged high-dose prednisone, only a stabilization of forced expiratory volume in 1 s could be achieved, and the disease course was complicated by respiratory infections resulting in further loss of lung function. The patient died 1 year later due to progression of metastatic disease. These 2 cases suggest that pulmonary IRAEs secondary to ICIs may present as isolated bronchitis or bronchiolitis, with variable outcomes following ICI withdrawal and systemic corticosteroids.

[Diaphragmatic paralysis and paresis†: review]. / Parésies et paralysies diaphragmatiques.

Diaphragmatic paresis/paralysis can be unilateral or bilateral. Its manifestations range from completely asymptomatically to global respiratory failure. Respiratory functional tests will reveal lowered respiratory pressures with a restrictive syndrome, and a decrease in vital capacity when lying in the supine position compared to sitting. Unilateral paresis is most often self-limited and mainly post-surgical. The bilateral dysfunction, observed in neuromuscular diseases, is often permanent. The treatment consists in the management of specific causes, the optimization of the treatment of comorbidities, and in some cases, diaphragmatic plication, ventilatory support or pacing of phrenic nerves.

La parésie/paralysie du diaphragme peut être uni- ou bilatérale. Elle peut se présenter de façon complètement asymptomatique ou aller jusqu'à l'insuffisance respiratoire globale. Les tests fonctionnels respiratoires révéleront des pressions respiratoires abaissées avec un syndrome restrictif, et une diminution de la capacité vitale en position couchée par rapport à assise. La parésie unilatérale est le plus souvent autolimitée et principalement d'étiologie postchirurgicale. L'atteinte bilatérale, principalement observée dans les maladies neuromusculaires, est souvent permanente. Le traitement consiste en une prise en charge des causes spécifiques, une optimisation du traitement des comor bidités, et dans certains cas une plicature diaphragmatique, un support ventilatoire ou un pacing des nerfs phréniques.

Added Value of Xpert MTB/RIF Ultra for Diagnosis of Pulmonary Tuberculosis in a Low-Prevalence Setting.

Xpert MTB/RIF (Xpert) for direct molecular detection of Mycobacterium tuberculosis and rifampin resistance from clinical specimens has dramatically improved the diagnosis of tuberculosis (TB). Xpert MTB/RIF Ultra (Ultra) is proposed as a substitute of Xpert with increased sensitivity and improved rifampin resistance detection. We evaluated the diagnostic performance of Ultra and Xpert for pulmonary TB diagnosis in a low-TB-burden setting. Performance of Ultra and Xpert were compared to culture on respiratory specimens from patients with suspected pulmonary TB (November 2016 to August 2018; n = 196) in Lausanne (Switzerland). Clinical data were used to investigate discrepant results. Correlation between semiquantitative result of Ultra and smear microscopy status for the detection of acid-fast bacilli (AFB) was established. The sensitivities of Xpert and Ultra were 82.9% (39/47) and 95.8% (45/47), respectively, when considering all culture-positive specimens, 100% (23/23) for both assays on smear-positive specimens, and 66.7% (16/24) and 91.7% (22/24) on smear-negative specimens. Using culture as gold standard, the specificities of Xpert and Ultra were 97.3% (145/149) and 96.64% (144/149), respectively. All the patients with Ultra-positive results with the new category "trace" were diagnosed with active TB based on clinical findings and microbiological culture. The semiquantitative results of both Xpert and of Ultra positively correlated with the semiquantitative result of AFB detection. Our data support an increased sensitivity of Ultra compared to Xpert in a low-prevalence setting. Correlation between the Ultra semiquantitative result and AFB burden can help in evaluating a patient's transmission potential.

Added diagnostic value of 16S rRNA gene pan-mycobacterial PCR for nontuberculous mycobacterial infections: a 10-year retrospective study.

The diagnosis of mycobacterial infections has been dramatically improved by the introduction of molecular methods aimed to reduce the time to diagnosis as compared with culture. The broad range pan-mycobacterial PCR can detect all the mycobacterial species directly from clinical specimens. We aimed to evaluate its usefulness and its clinical added value for the diagnosis of nontuberculous mycobacterial (NTM) infections. We performed a retrospective study (2003-2013) including 952 samples taken from 639 patients with clinical suspicion of NTM infection. The performance of smear microscopy, PCR and culture was established using clinical data to investigate discrepant results. We also compared the time to microbial diagnosis between the direct PCR and culture. The sensitivity, specificity, positive and negative predictive values of the PCR were 61.6% (53.5-69.1), 99.1% (98.2-99.6), 92.8% (85.8-96.5) and 93.4% (91.6-94.9), respectively, when considering all specimens. When considering smear-positive specimens and smear-negative specimens, the sensitivity was 81.6% and 40%, respectively. The sensitivity for pulmonary and extra-pulmonary smear-positive specimens was 85.2% versus 72.7%. The median time to identification at species level was 35 days (SD, 17.67) for culture and 6 days (SD, 2.67) for the PCR (when positive), which represents a 29-day shorter time to results (p < 0.0001). The 16S rRNA gene pan-mycobacterial PCR displays a substantial benefit in terms of time to diagnose NTM infections when compared with culture. Despite an excellent specificity, its sensitivity is yet limited in particular for smear-negative specimens, which might be improved by relying onto real-time PCRs.

Airway microbiota signals anabolic and catabolic remodeling in the transplanted lung.

BACKGROUND: Homeostatic turnover of the extracellular matrix conditions the structure and function of the healthy lung. In lung transplantation, long-term management remains limited by chronic lung allograft dysfunction, an umbrella term used for a heterogeneous entity ultimately associated with pathological airway and/or parenchyma remodeling. OBJECTIVE: This study assessed whether the local cross-talk between the pulmonary microbiota and host cells is a key determinant in the control of lower airway remodeling posttransplantation. METHODS: Microbiota DNA and host total RNA were isolated from 189 bronchoalveolar lavages obtained from 116 patients post lung transplantation. Expression of a set of 11 genes encoding either matrix components or factors involved in matrix synthesis or degradation (anabolic and catabolic remodeling, respectively) was quantified by real-time quantitative PCR. Microbiota composition was characterized using 16S ribosomal RNA gene sequencing and culture. RESULTS: We identified 4 host gene expression profiles, among which catabolic remodeling, associated with high expression of metallopeptidase-7, -9, and -12, diverged from anabolic remodeling linked to maximal thrombospondin and platelet-derived growth factor D expression. While catabolic remodeling aligned with a microbiota dominated by proinflammatory bacteria (eg, Staphylococcus, Pseudomonas, and Corynebacterium), anabolic remodeling was linked to typical members of the healthy steady state (eg, Prevotella, Streptococcus, and Veillonella). Mechanistic assays provided direct evidence that these bacteria can impact host macrophage-fibroblast activation and matrix deposition. CONCLUSIONS: Host-microbes interplay potentially determines remodeling activities in the transplanted lung, highlighting new therapeutic opportunities to ultimately improve long-term lung transplant outcome.

[What's new on asthma in primary care]. / Nouveautés concernant l'asthme en médecine de premier recours.

The international recommendations of the management of asthma have been modified last years. Several therapies used since long time have no place in the management of moderate asthma today. The use of targeted immunotherapies against phenotypes of asthma are used more and more. Inhalant therapies are becoming more targeted towards the patient's wishes. This article specifies the novelties in management of asthma for de general practitioner, including the use of short acting beta2-agonists, which are no longer to be used without inhaled corticosteroid.

Les recommandations internationales de la prise en charge de l'asthme ont été modifiées ces dernières années. Plusieurs thérapies utilisées de longue date n'ont plus leur place dans la prise en charge des asthmes modérés, et l'utilisation d'immunothérapies ciblées envers certains phénotypes d'asthme se répand. Les thérapies inhalées deviennent de plus en plus orientées vers la volonté du patient. Cet article précise les nouveautés dans la prise en charge de l'asthme à destination du praticien, notamment l'utilisation de bêta2-agonistes à courte durée d'action seuls qui n'ont plus leur place sans corticostéroïde inhalé.

[Obesity hypoventilation syndrome†: 2019's management]. / Syndrome obésité-hypoventilation†: prise en charge 2019.

Obesity hypoventilation syndrome is an underdiagnosed pathology, whose prevalence is increasing due to the progressively higher prevalence of obesity in the general population. Early detection allows early management and lowers the risk of acute exacerbation, hospitalization and mortality. The diagnosis is done by excluding other, pulmonary or extra pulmonary, reasons of hypercapnia; a nocturnal polygraphy is mandatory to diagnose an associated obstructive sleep apnea syndrome. The pneumological treatment is a ventilatory support by CPAP or biPAP (bilevel Positive Airways Pressure).

Le syndrome obésité-hypoventilation (SOH) est une pathologie sous-diagnostiquée, mais de plus en plus fréquente au vu de l'augmentation de la prévalence de l'obésité. Le dépistage précoce au cabinet du généraliste peut permettre une prise en charge rapide diminuant le risque d'exacerbation aiguë, d'hospitalisation et de mortalité. Le diagnostic repose sur l'exclusion d'autres causes - pulmonaires ou extrapulmonaires - d'hypercapnie ; une polygraphie nocturne est utile au diagnostic de syndrome des apnées obstructives du sommeil (SAOS), pathologie souvent associée. Le traitement pneumologique consiste en un support ventilatoire par CPAP ou biPAP (bilevel Positive Airways Pressure).

[Computer instruments for the management of isolated pulmonary nodule. Detectability and prediction of malignancy]. / Outils informatiques pour la prise en charge du nodule pulmonaire isolé - Détectabilité et prédiction de malignité.

Lung cancer remains the most common cause of cancer deaths in the world, but its mortality can be significantly reduced by diagnosis and early detection. Computerized resources were developed to assist radiologists in their management of the large volume of thoracic images to be analyzed. Their objective is the detection of pulmonary nodules with high sensitivity and a low rate of false-positives and the ability to differentiate benign and malignant nodules. The volume of a pulmonary nodule and its volume doubling time are essential to nodule management. Computer aided detection or diagnosis (CAD) software are not currently used in clinically settings on a routine basis . Significant advances are expected due to the implementation of the artificial intelligence systems who will probably be integrated into the multidisciplinary management of any pulmonary nodule.

Le cancer du poumon reste la principale cause de décès par cancer dans le monde. Sa mortalité peut être significativement réduite par un diagnostic et un dépistage précoce. Des outils informatiques ont été développés afin d'aider les radiologues à gérer la quantité d'images thoraciques à analyser. Ils ont pour objectif la détection des nodules pulmonaires avec une haute sensibilité et un taux faible de faux positifs, mais aussi la différenciation des nodules bénins et malins. Le volume d'un nodule pulmonaire et le temps de doublement déterminent la suite de la prise en charge de ce nodule. Ces deux paramètres sont inclus dans la plupart des recommandations actuelles. Les logiciels de détection assistés par ordinateur (CAD) ne sont pas utilisés en routine clinique actuellement. Des avancées dans ce domaine sont attendues en utilisant l'intelligence artificielle, notamment dans le cadre de la prise de décision multidisciplinaire.

GLI 2012 equations define few spirometric anomalies in the general population: the PneumoLaus study.

BACKGROUND: Reduced lung function predicts increased mortality, but its prevalence may vary depending on definition considered, use of bronchodilation and applied reference values. We aimed to assess lung function abnormalities in Lausanne, Switzerland, and their association with clinical history. METHODS: In a general population sample, spirometry was performed and bronchodilation applied if the ratio forced expiratory volume in 1 s (FEV1) / forced vital capacity (FVC) or the FVC was below the lower limit of normal (LLN) according to Global Lung Function Initiative 2012 references. Results for FEV1/FVC according to the LLN were compared to the 0.7 fixed ratio. Respiratory risk factors, symptoms and self-reported respiratory diagnoses were recorded through a questionnaire. RESULTS: Out of the 3342 included subjects, 3.8% had chronic obstruction and 2.5% reversible obstruction when using the LLN; possible lung restriction alone was present in 1.8%, and associated with chronic obstruction in 0.4%. Ever smokers had a higher prevalence of abnormal spirometry, chronic obstruction and reversible obstruction; there was no difference with regard to possible restriction. Overall, chronic airway obstruction was found in 8.9% of current smokers, 4.6% of former smokers and 1.5% of never smokers. Only one third of participants with chronic obstruction were aware of a respiratory disease. CONCLUSION: Prevalence of abnormal lung function in the population of Lausanne is low. This may be due to a low rate of ever-smokers, the application of a full bronchodilation dose, but also to inherent characteristics of this population.

Diagnosis and Management of Asthma - The Swiss Guidelines.

The Global Initiative for Asthma (GINA) is a network of individuals, organizations, and public health officials that was established to disseminate information about the care of patients with asthma and to improve asthma care. The GINA ("Global Strategy for Asthma Management and Prevention") report has been updated annually since 2002. Due to new knowledge and therapeutic development in the field, the Swiss Respiratory Society felt the need to provide a new document that is based on both the available literature and the recommendations of the 2016 GINA report. Key new features of the 2016 GINA report include a "new" definition of asthma, underscoring its heterogeneous nature, and the core elements of variable symptoms and variable expiratory airflow limitation; the importance of confirming the diagnosis of asthma in order to minimize both under- and overtreatment; practical tools for the assessment of symptom control and risk factors for adverse outcomes; a comprehensive approach to asthma management that acknowledges the foundational role of inhaled corticosteroid therapy, but also provides a framework for individualizing patient care; an emphasis on maximizing the benefit of available medications by addressing common problems such as incorrect inhaler technique and poor adherence; a continuum of care for worsening asthma, starting with early self-management and progressing to primary care or acute care management; and diagnosis of the asthma/chronic obstructive pulmonary disease overlap syndrome. This document is meant to advice the key stakeholders on the diagnosis and management of asthma and highlights the need to individualize the care of each and every asthmatic patient.

Diagnosis, Prevention and Treatment of Stable COPD and Acute Exacerbations of COPD: The Swiss Recommendations 2018.

The Swiss National Guidelines 2013 for chronic obstructive pulmonary disease have been revised in order to acknowledge recent progress in diagnosis and management of this disease. The resulting new Swiss recommendations are based on best evidence from the literature, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2018 report and other published national guidelines. Misdiagnosis of chronic obstructive pulmonary disease is common and means that patients do not always receive optimal treatment. To improve the management of patients with chronic obstructive pulmonary disease in Switzerland, these recommendations encourage a more comprehensive assessment of patients, based on the combined assessment of symptoms, degree of airflow limitation, risk of exacerbation and the presence of comorbidities. Recommendations for evidence-based preventive measures, as well as pharmacological and non-pharmacological strategies for the management of both stable and acute exacerbations of chronic obstructive pulmonary disease are provided in this update.

[When home become breathtaking]. / Quand la maison nous coupe le souffle.

We spend most of our time indoor and mainly at home. Thermal insulation has greatly improved in the last decades, thus leading to deficiency in ventilation and poor indoor air quality. Many studies suggest that there is a link between respiratory diseases and various indoor air pollutants such as moulds, allergens, volatile organic compounds, combustible smoke, house dust mite, radon or asbestos. This article reviews the most common pathogenic pollutants at home as well as their sources and related respiratory diseases. Preventive measures are further presented for every category of contaminant.

Nous passons la plupart de notre temps à l'intérieur et le plus souvent à notre domicile. Durant les dernières décennies, l'amélioration de l'isolation thermique des habitats a entraîné une diminution de la ventilation des espaces clos et un appauvrissement de la qualité de l'air intérieur. Plusieurs études suggèrent une association entre des symptômes ou pathologies respiratoires et différents contaminants de l'air intérieur comme les moisissures, les animaux domestiques, les composés organiques volatiles, les produits de combustion, les acariens, le radon ou l'amiante. Cet article passe en revue les substances pathogènes les plus fréquentes dans le milieu domestique, ainsi que leurs sources et les pathologies respiratoires associées. Des recommandations sont proposées pour chaque catégorie de contaminant.

[Noninvasive ventilation for chronic hypercapnic respiratory failure]. / Rôle de la ventilation non invasive dans l'insuffisance respiratoire hypercapnique chronique.

Chronic hypercapnic respiratory failure is essentially a ventilatory failure. Noninvasive ventilation (NIV ) reduces the work of breathing, improves pulmonary compliance and alveolar ventilation, corrects gas exchange disorders and improves dyspnoea. However, treatment efficacy depends on the underlying pathology, on correct timing and on patient compliance. In this context, the principal role of the primary care physician is to search for, at every visit of at risk patients, signs and symptoms of ventilatory failure and to refer the patient to a respiratory care specialist. He also plays a role in the follow up of patients under noninvasive ventilation for the detection of clinical parameters suggesting NIV failure.

L'insuffisance respiratoire hypercapnique chronique est essentiellement une défaillance ventilatoire. La ventilation non invasive (VNI) diminue le travail des muscles respiratoires, augmente la compliance thoracique, améliorant ainsi la dyspnée et les troubles des échanges gazeux. Toutefois, l'efficacité du traitement dépend de la pathologie sous-jacente, du bon timing d'initiation et de la compliance du patient. Dans ce contexte, le rôle principal du médecin de premier recours consiste à rechercher, lors de chaque visite médicale de patients à risque, des signes et symptômes de défaillance ventilatoire qui nécessitent de référer le patient à un pneumologue. Son rôle est aussi important dans le suivi des patients ventilés pour la détection précoce des paramètres cliniques suggérant un échec de VNI.

[Systemic biomarkers in respiratory tract infections]. / Biomarqueurs systèmiques pour les infections respiratoires.

Respiratory tract infections represent a major cause of morbidity and mortality despite the progress made in their diagnosis and treatment. Since the clinical presentation of a viral or bacterial infection is often similar, the identification of a biomarker that could guide the clinician whether or not to introduce an antibiotic therapy is crucial. C-reactive protein and procalcitonin are the most commonly used biomarkers as a diagnostic tool for respiratory tract infections. New biomarkers show promising results for assessing the severity of infection and identifying patients at risk for complications. However, the use of biomarkers has limitations and the diagnosis of a bacterial infection should not be based solely on the measurement of a biomarker.

Malgré le progrès effectué pour le diagnostic et le traitement des infections respiratoires, ces dernières représentent une cause de morbidité et mortalité importante. La présentation clinique d'une infection virale ou bactérienne étant souvent identique, l'identification d'un biomarqueur qui pourrait aider le clinicien à la décision d'introduire ou pas un traitement antibiotique est cruciale. La protéine C-réactive et la procalcitonine sont les biomarqueurs les plus fréquemment utilisés comme aide au diagnostic. Des nouveaux biomarqueurs montrent des résultats prometteurs pour évaluer la sévérité de l'infection et les patients à risque de complication. Toutefois, l'utilisation des biomarqueurs présente des limitations et le diagnostic d'une infection bactérienne ne doit en aucun cas être basé uniquement sur la mesure d'un biomarqueur.