An integrated molecular risk score early in life for subsequent childhood asthma risk

BACKGROUND

Numerous children present with early wheeze symptoms, yet solely a subgroup develops childhood asthma. Early identification of children at risk is key for clinical monitoring, timely patient-tailored treatment, and preventing chronic, severe sequelae. For early prediction of childhood asthma, we aimed to define an integrated risk score combining established risk factors with genome-wide molecular markers at birth, complemented by subsequent clinical symptoms/diagnoses (wheezing, atopic dermatitis, food allergy).

METHODS

Three longitudinal birth cohorts (PAULINA/PAULCHEN, n = 190 + 93 = 283, PASTURE, n = 1133) were used to predict childhood asthma (age 5-11) including epidemiological characteristics and molecular markers: genotype, DNA methylation and mRNA expression (RNASeq/NanoString). Apparent (ap) and optimism-corrected (oc) performance (AUC/R2) was assessed leveraging evidence from independent studies (Naïve-Bayes approach) combined with high-dimensional logistic regression models (LASSO).

RESULTS

Asthma prediction with epidemiological characteristics at birth (maternal asthma, sex, farm environment) yielded an ocAUC = 0.65. Inclusion of molecular markers as predictors resulted in an improvement in apparent prediction performance, however, for optimism-corrected performance only a moderate increase was observed (upto ocAUC = 0.68). The greatest discriminate power was reached by adding the first symptoms/diagnosis (up to ocAUC = 0.76; increase of 0.08, p = .002). Longitudinal analysis of selected mRNA expression in PASTURE (cord blood, 1, 4.5, 6 years) showed that expression at age six had the strongest association with asthma and correlation of genes getting larger over time (r = .59, p < .001, 4.5-6 years).

CONCLUSION

Applying epidemiological predictors alone showed moderate predictive abilities. Molecular markers from birth modestly improved prediction. Allergic symptoms/diagnoses enhanced the power of prediction, which is important for clinical practice and for the design of future studies with molecular markers.

Severe asthma care trajectories: the French RAMSES cohort

Background

The French RAMSES study is an observational prospective multicentre real-life cohort including severe asthmatic subjects. The objective of the study was to compare the characteristics of patients, in terms of phenotype and asthma care trajectories, between those managed by tertiary referral centres (TRCs) or secondary care centres (SCCs).

Methods

Patients were prospectively recruited and enrolled for a 5-year follow-up. Patients' characteristics were analysed at inclusion and compared between TRCs and SCCs.

Results

52 centres (24 TRCs and 28 SCCs) included 2046 patients: 1502 (73.4%) were included by a TRC and 544 (26.6%) by a SCC. Patients were mainly women (62%), 53±15 years old, 67% with Asthma Control Test <20; at inclusion, 14% received oral corticosteroids (OCS) and 66% biologics. Compared with the SCC group, the TRC group had more frequent comorbidities and lower blood eosinophil counts (262 versus 340 mm-3; p=0.0036). OCS and biologics use did not differ between groups, but patients in the TRC group benefited more frequently from an educational programme (26% versus 18%; p=0.0008) and received more frequently two or more sequential lines of biologics (33% versus 24%; p=0.0105). In-depth investigations were more frequently performed in the TRC group (allergy tests: 74% versus 62%; p<0.0001; exhaled nitric oxide fraction: 56% versus 21%; p<0.0001; induced sputum: 6% versus 3%; p=0.0390).

Conclusions

Phenotypes and care trajectories differed in the RAMSES cohort between SCCs and TRCs, probably related to different levels of asthma severity and differences in medical resources and practices among centres. This highlights the need for standardisation of severe asthma care.

Impact of pharmacological and non-pharmacological interventions on mortality in chronic obstructive pulmonary disease (COPD) patients

PURPOSE

This review aimed to summarise evidence about the impact of pharmacological and non-pharmacological interventions on survival in COPD patients.

METHODS

We performed a narrative literature review on the effect of pharmacological and non-pharmacological interventions on survival in COPD patients.

RESULTS

Inhaled therapies are central to reduce symptoms in COPD. In particular, inhaled steroids seem to have the greatest effect on mortality. Despite the anti-inflammatory effects attributed to statins, their benefit in COPD has been shown only in cases of combined cardiovascular diseases. The use of beta-blockers in COPD has not been associated with increased COPD-related mortality and a beneficial effect on all-cause mortality has even been shown in COPD patients with cardiovascular diseases. Influenza and pneumococcal vaccination reduced the occurrence of exacerbations and mortality due to COPD. In addition, long-term oxygen therapy (LTOT) (≥15h/day) in COPD patients with severe hypoxemia had a positive effect on survival. Regarding non-pharmacological interventions, it has been demonstrated that smoking cessation, treatment compliance and nutritional supplementation for underweight patients also have a positive effect on survival. Non-invasive ventilation results were dependent on patient PaCO2 levels. In patients with advanced COPD, further prospective studies are needed to know the effect of bronchoscopic lung volume reduction and lung transplant on COPD survival. Regarding lung transplant, a survival benefit in patients with a pre-transplant BODE score of ≥7 has been shown in retrospective studies.

CONCLUSION

Most of the studies did not evaluate survival as the main criteria and further long-term studies on the global management of COPD are required.

[The role of the cardiopulmonary exercise test and pulmonary rehabilitation in long COVID-19]

INTRODUCTION

Long COVID refers to persistent symptoms, lasting more than 4 weeks after acute SARS-CoV-2 infection, even though the infection itself has been successfully controlled and remedied. Patient complaints are diverse, and the underlying physiopathological mechanisms are not well understood. Dyspnea and muscle fatigue are among the most commonly reported symptoms.

STATE OF THE ART

Cardiopulmonary exercise test (CPET) has been recognized as a useful tool in investigation of unexplained dyspnea. In patients with chronic lung disease, pulmonary rehabilitation is a program designed to counteract dyspnea, to increase exercise capacity and to improve quality of life.

PERSPECTIVES

Publications on CPET and pulmonary rehabilitation are needed in order to deepen comprehension and enhance management of long-COVID-19.

CONCLUSIONS

CPET reports have shown that symptoms persisting in the aftermath of acute SARS-CoV-2 infection may be related to deconditioning, a common occurrence after ICU stay, to cardiac dysautonomia subsequent to critical infections and, finally, to dysfunctional breathing subsequent to mild infections. These findings justify pulmonary rehabilitation, which has proven to be effective regardless of the severity of the initial infection, not only immediately after hospital discharge, but also at later points in time.

[A rare and atypical form of tularemia in a context of immunodepression]

INTRODUCTION

We present an original severe case of tularemia with cutaneous damage, lymphadenopathy and pericarditis ; pathology of increasing incidence in Europe due to global warming.

OBSERVATION

A 33-years-old women consulted emergency unit for altered general condition, anorexia, hyperthermia at 38,3°C, dyspnea and dry cough evolving for few days. Her only history was Crohn's disease with introduction of an anti-TNF alpha for 3 months. The interrogation found regular forest walks ». Treatment with Amoxicillin/clavulanic acid 1g 3 times daily and curative anticoagulation was started after the initial diagnosis of infectious pneumonia associated with pulmonary embolism. The patient reconsulted 2 weeks later for clinical deterioration associated with skin lesions. The chest CT scan showed increased mediastinal lymphadenopathy and a circumferential pericardial effusion ; quantified at 5mm on transthoracic ultrasound. Tularemia serology was positive in IgG at 400IU/mL. Despite an adapted antibiotic therapy with Ciprofloxacin, the patient presented a new brutal clinical deterioration. A pericardiocentesis was performed and the analysis revealed a predominantly neutrophilic exudate and a strongly positive PCR Francisella tularensis. Gentamicin 5mg/kg was associated allowing a resolution of the symptoms.

CONCLUSION

Tularemia is one of the pathologies whose atypical presentation with pericarditis (favored by a certain immunodepression) worsens the prognosis. Global warming influences the epidemiology of inoculation diseases, including tularemia, making it more frequent.

Continuous Rather Than Solely Early Farm Exposure Protects From Hay Fever Development

BACKGROUND

An important window of opportunity for early-life exposures has been proposed for the development of atopic eczema and asthma.

OBJECTIVE

However, it is unknown whether hay fever with a peak incidence around late school age to adolescence is similarly determined very early in life.

METHODS

In the Protection against Allergy-Study in Rural Environments (PASTURE) birth cohort potentially relevant exposures such as farm milk consumption and exposure to animal sheds were assessed at multiple time points from infancy to age 10.5 years and classified by repeated measure latent class analyses (n = 769). Fecal samples at ages 2 and 12 months were sequenced by 16S rRNA. Hay fever was defined by parent-reported symptoms and/or physician's diagnosis of hay fever in the last 12 months using questionnaires at 10.5 years.

RESULTS

Farm children had half the risk of hay fever at 10.5 years (adjusted odds ratio [aOR] 0.50; 95% CI 0.31-0.79) than that of nonfarm children. Whereas early life events such as gut microbiome richness at 12 months (aOR 0.66; 95% CI 0.46-0.96) and exposure to animal sheds in the first 3 years of life (aOR 0.26; 95% CI 0.06-1.15) were determinants of hay fever, the continuous consumption of farm milk from infancy up to school age was necessary to exert the protective effect (aOR 0.35; 95% CI 0.17-0.72).

CONCLUSIONS

While early life events determine the risk of subsequent hay fever, continuous exposure is necessary to achieve protection. These findings argue against the notion that only early life exposures set long-lasting trajectories.

Evaluation of long-term sequelae by cardiopulmonary exercise testing 12 months after hospitalization for severe COVID-19

BACKGROUND

Cardiopulmonary exercise testing (CPET) is an important clinical tool that provides a global assessment of the respiratory, circulatory and metabolic responses to exercise which are not adequately reflected through the measurement of individual organ system function at rest. In the context of critical COVID-19, CPET is an ideal approach for assessing long term sequelae.

METHODS

In this prospective single-center study, we performed CPET 12 months after symptom onset in 60 patients that had required intensive care unit treatment for a severe COVID-19 infection. Lung function at rest and chest computed tomography (CT) scan were also performed.

RESULTS

Twelve months after severe COVID-19 pneumonia, dyspnea was the most frequently reported symptom although only a minority of patients had impaired respiratory function at rest. Mild ground-glass opacities, reticulations and bronchiectasis were the most common CT scan abnormalities. The majority of the patients (80%) had a peak O₂ uptake (V'O₂) considered within normal limits (median peak predicted O₂ uptake (V'O₂) of 98% [87.2-106.3]). Length of ICU stay remained an independent predictor of V'O₂. More than half of the patients with a normal peak predicted V'O₂ showed ventilatory inefficiency during exercise with an abnormal increase of physiological dead space ventilation (VD/Vt) (median VD/VT of 0.27 [0.21-0.32] at anaerobic threshold (AT) and 0.29 [0.25-0.34] at peak) and a widened median peak alveolar-arterial gradient for O₂ (35.2 mmHg [31.2-44.8]. Peak PetCO₂ was significantly lower in subjects with an abnormal increase of VD/Vt (p = 0.001). Impairments were more pronounced in patients with dyspnea. Peak VD/Vt values were positively correlated with peak D-Dimer plasma concentrations from blood samples collected during ICU stay (r² = 0.12; p = 0.02) and to predicted diffusion capacity of the lung for carbon monoxide (D_LCO) (r² =  - 0.15; p = 0.01).

CONCLUSIONS

Twelve months after severe COVID-19 pneumonia, most of the patients had a peak V'O₂ considered within normal limits but showed ventilatory inefficiency during exercise with increased dead space ventilation that was more pronounced in patients with persistent dyspnea.

TRIAL REGISTRATION

NCT04519320 (19/08/2020).

Trajectories of cough without a cold in early childhood and associations with atopic diseases

BACKGROUND

Although children can frequently experience a cough that affects their quality of life, few epidemiological studies have explored cough without a cold during childhood.

OBJECTIVES

The objective of the study was to describe the latent class trajectories of cough from one to 10 years old and analyse their association with wheezing, atopy and allergic diseases.

METHODS

Questions about cough, wheeze and allergic diseases were asked at 1, 1.5, 2, 3, 4, 5, 6 and 10 years of age in the European prospective cohort of Protection against Allergy: STUdy in Rural Environment (PASTURE). Specific IgE assays were performed at 10 years of age. Questions regarding a cough without a cold were used to build a latent class model of cough over time.

RESULTS

Among the 961 children included in the study, apart from the never/infrequent trajectory (59.9%), eight trajectories of cough without a cold were identified: five grouped acute transient classes (24.1%), moderate transient (6.8%), late persistent (4.8%) and early persistent (4.4%). Compared with the never/infrequent trajectory, the other trajectories were significantly associated with wheezing, asthma and allergic rhinitis. For asthma, the strongest association was with the early persistent trajectory (OR_a  = 31.00 [14.03-68.51]), which was inversely associated with farm environment (OR_a  = 0.39 [0.19-0.77]) and had a high prevalence of cough triggers and unremitting wheeze. Late and early persistent trajectories were also associated with food allergy. Atopic sensitization was only associated with the late persistent trajectory.

CONCLUSION

Late and early persistent coughs without a cold are positively associated with atopic respiratory diseases and food allergy. Children having recurrent cough without a cold with night cough and triggers would benefit from an asthma and allergy assessment. Growing up on a farm is associated with reduced early persistent cough.

[Markers of severity and predictors of response to treatment in severe asthma]

Asthma is a multifactorial disease with complex pathophysiology. Knowledge of its immunopathology and inflammatory mechanisms is progressing and has led to the development over recent years of increasingly targeted therapeutic strategies. The objective of this review is to pinpoint the different predictive markers of asthma severity and therapeutic response. Obesity, nasal polyposis, gastroesophageal reflux disease and intolerance to aspirin have all been considered as clinical markers associated with asthma severity, as have functional markers such as bronchial obstruction, low FEV1, small daily variations in FEV1, and high FeNO. While sinonasal polyposis and allergic comorbidities are associated with better response to omalizumab, nasal polyposis or long-term systemic steroid use are associated with better response to antibodies targeting the IL5 pathway. Elevated total IgE concentrations and eosinophil counts are classic biological markers regularly found in severe asthma. Blood eosinophils are predictive biomarkers of response to anti-IgE, anti-IL5, anti-IL5R and anti-IL4R biotherapies. Dupilumab is particularly effective in a subgroup of patients with marked type 2 inflammation (long-term systemic corticosteroid therapy, eosinophilia≥150/μl or FENO>20 ppb). Chest imaging may help to identify severe patients by seeking out bronchial wall thickening and bronchial dilation. Study of the patient's environment is crucial insofar as exposure to tobacco, dust mites and molds, as well as outdoor and indoor air pollutants (cleaning products), can trigger asthma exacerbation. Wider and more systematic use of markers of severity or response to treatment could foster increasingly targeted and tailored approaches to severe asthma.

Result of one-year, prospective follow-up of intensive care unit survivors after SARS-CoV-2 pneumonia

Introduction

Survivors of viral ARDS are at risk of long-term physical, functional and neuropsychological complications resulting from the lung injury itself, but also from potential multiorgan dysfunction, and the long stay in the intensive care unit (ICU). Recovery profiles after severe SARS-CoV-2 pneumonia in intensive care unit survivors have yet to be clearly defined.

Material and methods

The goal of this single-center, prospective, observational study was to systematically evaluate pulmonary and extrapulmonary function at 12 months after a stay in the ICU, in a prospectively identified cohort of patients who survived SARS-CoV-2 pneumonia. Eligible patients were assessed at 3, 6 and 12 months after onset of SARS-CoV-2. Patients underwent physical examination, pulmonary function testing, chest computed tomography (CT) scan, a standardized six-minute walk test with continuous oximetry, overnight home respiratory polygraphy and have completed quality of life questionnaire. The primary endpoint was alteration of the alveolar–capillary barrier compared to reference values as measured by DLCO, at 12 months after onset of SARS-CoV-2 symptoms.

Results

In total, 85 patients (median age 68.4 years, (interquartile range [IQR] = 60.1–72.9 years), 78.8% male) participated in the trial. The median length of hospital stay was 44 days (IQR: 20–60) including 17 days in ICU (IQR: 11–26). Pulmonary function tests were completed at 3 months (n = 85), 6 months (n = 80), and 12 months (n = 73) after onset of symptoms. Most patients showed an improvement in DLCO at each timepoint (3, 6, and 12 months). All patients who normalized their DLCO did not subsequently deteriorate, except one. Chest CT scans were abnormal in 77 patients (96.3%) at 3 months and although the proportion was the same at 12 months, but patterns have changed.

Conclusion

We report the results of a comprehensive evaluation of 85 patients admitted to the ICU for SARS-CoV-2, at one-year follow-up after symptom onset. We show that most patients had an improvement in DLCO at each timepoint.

Trial registration: Clinical trial registration number: NCT04519320.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-00997-8.

The most interesting findings were that most patients showed an improvement in their DLCO at 3, 6, and 12 months, and all patients but one who normalized their DLCO did not deteriorate afterwards. Only 11% of patients had persistent impairment of DLCO at 1 year.

Prevalence and Characteristics of Sleep Apnea in Intensive Care Unit Survivors After SARS-CoV-2 Pneumonia

BACKGROUND

Sleep apnea (SA) was reported as possibly exacerbating symptoms of COVID-19, a disease induced by SARS-CoV-2 virus. The same comorbidities are common with both pathologies. This study aimed to estimate the prevalence, characteristics of SA and variation in AHI three months after severe COVID-19 requiring intensive care unit (ICU) admission.

METHODS

A prospective cohort of patients admitted to ICU for severe COVID-19 underwent an overnight home polygraphy 3 months after onset of symptoms, as part of a comprehensive follow-up program (pulmonary function tests, 6-minute walk tests and chest CT-scan). Patients with an apnea hypopnea index (AHI) ≥5 were considered as having SA. We performed a comparative descriptive analysis of 2 subgroups according to the existence, severity of SA and indication for effective SA treatment: patients with absent or mild SA (AHI <15) vs patients with moderate to severe SA (AHI ≥15).

RESULTS

Among 68 patients included, 62 (91%) had known comorbidities (34 hypertension, 21 obesity, 20 dyslipidemia, 16 type 2 diabetes). It has been observed a preexisting SA for 13 patients (19.1%). At 3 months, 62 patients (91%) had SA with 85.5% of obstructive events. Twenty-four patients had no or a mild SA (AHI <15) and 44 had moderate to severe SA (AHI ≥15). Ischemic heart disease exclusively affected the moderate to severe SA group. Except for thoracic CT-scan which revealed less honeycomb lesions, COVID-19 symptoms were more severe in the group with moderate to severe SA, requiring a longer curarization, more prone position sessions and more frequent tracheotomy.

CONCLUSION

SA involved 91% of patients in our population at 3 months of severe COVID-19 and was mainly obstructive type. Although SA might be a risk factor as well as consequences of ICU care in severe COVID-19 infection, our results underline the importance of sleep explorations after an ICU stay for this disease.

Activation of Resolution Pathways to Prevent and Fight Chronic Inflammation: Lessons From Asthma and Inflammatory Bowel Disease

Formerly considered as a passive process, the resolution of acute inflammation is now recognized as an active host response, with a cascade of coordinated cellular and molecular events that promotes termination of the inflammatory response and initiates tissue repair and healing. In a state of immune fitness, the resolution of inflammation is contained in time and space enabling the restoration of tissue homeostasis. There is increasing evidence that poor and/or inappropriate resolution of inflammation participates in the pathogenesis of chronic inflammatory diseases, extending in time the actions of pro-inflammatory mechanisms, and responsible in the long run for excessive tissue damage and pathology. In this review, we will focus on how resolution can be the target for therapy in "Th1/Th17 cell-driven" immune diseases and "Th2 cell-driven" immune diseases, with inflammatory bowel diseases (IBD) and asthma, as relevant examples. We describe the main cells and mediators stimulating the resolution of inflammation and discuss how pharmacological and dietary interventions but also life style factors, physical and psychological conditions, might influence the resolution phase. A better understanding of the impact of endogenous and exogenous factors on the resolution of inflammation might open a whole area in the development of personalized therapies in non-resolving chronic inflammatory diseases.

FACS - based isolation of human eosinophils allows purification of high quality RNA

Here we extensively describe a FACS-based protocol for isolating intact non-stained human eosinophils from peripheral blood; a stop forward from our recently published initial study. This method of purification could be accomplished in <3 h with only small volumes of whole blood necessary, even in healthy subjects generally exhibiting low levels of circulating eosinophils. Eosinophil activation during the isolation steps appeared to be minimal and this purification procedure yielded high quality RNA. Moreover, these FACS-isolated eosinophils had prolonged viability in culture and were suitable for further activation assays.

Early Intravascular Events Are Associated with Development of Acute Respiratory Distress Syndrome. A Substudy of the LIPS-A Clinical Trial

RATIONALE

Acute respiratory distress syndrome (ARDS) is a devastating illness with limited therapeutic options. A better understanding of early biochemical and immunological events in ARDS could inform the development of new preventive and treatment strategies.

OBJECTIVES

To determine select peripheral blood lipid mediator and leukocyte responses in patients at risk for ARDS.

METHODS

Patients at risk for ARDS were randomized as part of a multicenter, double-blind clinical trial of aspirin versus placebo (the LIPS-A [Lung Injury Prevention Study with Aspirin] trial; NCT01504867). Plasma thromboxane B2 (TXB2), aspirin-triggered lipoxin A4 (15-epi-LXA4, ATL), and peripheral blood leukocyte number and activation were determined on enrollment and after treatment with either aspirin or placebo.

MEASUREMENTS AND MAIN RESULTS

Thirty-three of 367 subjects (9.0%) developed ARDS after randomization. Baseline ATL levels, total monocyte counts, intermediate monocyte counts, and monocyte-platelet aggregates were associated with the development of ARDS. Peripheral blood neutrophil count and monocyte-platelet aggregates significantly decreased over time. Of note, nine subjects developed ARDS after randomization yet before study drug initiation, including seven subjects assigned to aspirin treatment. Subjects without ARDS at the time of first dose demonstrated a lower incidence of ARDS with aspirin treatment. Compared with placebo, aspirin significantly decreased TXB2 and increased the ATL/TXB2 ratio.

CONCLUSIONS

Biomarkers of intravascular monocyte activation in at-risk patients were associated with development of ARDS. The potential clinical benefit of early aspirin for prevention of ARDS remains uncertain. Together, results of the biochemical and immunological analyses provide a window into the early pathogenesis of human ARDS and represent potential vascular biomarkers of ARDS risk. Clinical trial registered with www.clinicaltrials.gov (NCT01504867).

Towards targeting resolution pathways of airway inflammation in asthma

Asthma is a chronic disorder characterized by persistent inflammation of the airways with mucosal infiltration of eosinophils, T lymphocytes, and mast cells, and release of proinflammatory cytokines and lipid mediators. The natural resolution of airway inflammation is now recognized as an active host response, with highly coordinated cellular events under the control of endogenous pro-resolving mediators that enable the restoration of tissue homeostasis. Lead members of proresolving mediators are enzymatically derived from essential polyunsaturated fatty acids, including arachidonic acid-derived lipoxins, eicosapentaenoic acid-derived E-series resolvins, and docosahexaenoic acid-derived D-series resolvins, protectins, and maresins. Functionally, these specialized pro-resolving mediators can limit further leukocyte recruitment, induce granulocyte apoptosis, and enhance efferocytosis by macrophages. They can also switch macrophages from classical to alternatively activated cells, promote the return of non-apoptotic cells to lymphatics and blood vessels, and help initiate tissue repair and healing. In this review, we highlight cellular and molecular mechanisms for successful resolution of inflammation, and describe the main specialized pro-resolving mediators that drive these processes. Furthermore, we report recent data suggesting that the pathobiology of severe asthma may result in part from impaired resolution of airway inflammation, including defects in the biosynthesis of these specialized pro-resolving mediators. Finally, we discuss resolution-based therapeutic perspectives.

[New inflammatory pathways in asthma: the pathophysiology of asthma revisited]

In the same way, the clinical presentation of asthma may differ from one individual to another, it has been demonstrated that the nature and extent of bronchial inflammation in asthma also varies among subjects. Thus, the composition of the bronchial inflammatory infiltrate makes it possible to distinguish at least two molecular signatures, each with a distinct pathophysiology. A "Th2" profile, the most frequent, with increased total E immunoglobulin levels, the presence of eosinophils and "Th2" cytokines (IL-4, IL-5 and IL-13) in the airways. It includes classical allergic asthma related to an abnormal adaptive immune response but also a subtype of non-allergic asthma where eosinophil accumulation is under the control of the innate immune system via a newly identified cell population, called type 2 innate lymphoid cells (ILC2); type 2-driven asthma is thus an emerging nomenclature for a common subtype of asthma. And a "non-Th2" profile, including the accumulation of neutrophils in the airways, with new pathways beginning to be uncovered.

Natural killer cell-mediated inflammation resolution is disabled in severe asthma

Severe asthma is typically characterized by chronic airway inflammation that is refractory to corticosteroids and associated with excess morbidity. Patients were recruited into the National Heart, Lung, and Blood Institute-sponsored Severe Asthma Research Program and comprehensively phenotyped by bronchoscopy. Bronchoalveolar lavage (BAL) cells were analyzed by flow cytometry. Compared with healthy individuals (n = 21), patients with asthma (n = 53) had fewer BAL natural killer (NK) cells. Patients with severe asthma (n = 29) had a marked increase in the ratios of CD4⁺ T cells to NK cells and neutrophils to NK cells. BAL NK cells in severe asthma were skewed toward the cytotoxic CD56^dim subset, with significantly increased BAL fluid levels of the cytotoxic mediator granzyme A. The numbers of BAL CD56^dim NK cells and CCR6^-CCR4^- T helper 1-enriched CD4⁺ T cells correlated inversely with lung function [forced expiratory volume in 1 s (FEV₁) % predicted] in asthma. Relative to cells from healthy controls, peripheral blood NK cells from asthmatic patients had impaired killing of K562 myeloid target cells despite releasing more cytotoxic mediators. Ex vivo exposure to dexamethasone markedly decreased blood NK cell lysis of target cells and cytotoxic mediator release. NK cells expressed airway lipoxin A₄/formyl peptide receptor 2 receptors, and in contrast to dexamethasone, lipoxin A₄-exposed NK cells had preserved functional responses. Together, our findings indicate that the immunology of the severe asthma airway is characterized by decreased NK cell cytotoxicity with increased numbers of target leukocytes, which is exacerbated by corticosteroids that further disable NK cell function. These failed resolution mechanisms likely contribute to persistent airway inflammation in severe asthma.

[Omalizumab: Beyond anti-IgE properties]

INTRODUCTION

Omalizumab is used as a treatment for severe allergic asthma. Its intended mechanism of action is based on its anti-IgE proprieties. However, recent studies have highlighted other mechanisms of action.

STATE OF THE ART

Omalizumab treatment is associated with a decrease in the number of dendritic cells, T and B lymphocytes and eosinophils. This anti-inflammatory activity is characterized by a decrease in the levels of several cytokines involved in the recruitment, activation and survival of eosinophils and mastocytes, and in a Th2 orientation of the immune response. A modulation of bronchial remodeling by omalizumab has recently been shown. A decrease in the production of extracellular matrix components and in the proliferation of smooth muscle cells could be involved in this modulation. These mechanisms of action could explain in part the clinical efficiency of omalizumab in non-allergic conditions such as non-allergic asthma, non-allergic urticaria or nasal polyposis.

CONCLUSION

A precise knowledge of the mechanisms of action of omalizumab could allow the identification of biomarkers predictive of efficacy of this treatment. These could be useful tools in the phenotyping of severe asthma.

[How to consider triggers and comorbid conditions in severe asthma in adults]

Triggers and precipitating factors as well as comorbid conditions are associated with asthma and severe asthma. They interfere with the potential to control the disease and represent an additional burden for the patients. Allergen exposure is well known to induce loss of control and exacerbations. Comorbid conditions belong to various fields of medicines including cardiovascular diseases, osteoporosis, obesity and sleep apneas and GERD. They should be diagnosed and treated for themselves according to the best state of the art. Their precise role et their contribution to severe asthma pathophysiology is largely unknown and longitudinal cohort studies are needed to better understand and treat the patients with severe asthma.

Innate immunity is a key factor for the resolution of inflammation in asthma

The resolution of inflammation is an integral and natural part of the physiological response to tissue injury, infection and allergens or other noxious stimuli. Resolution is now recognised as an active process with highly regulated cellular and biochemical events. Recent discoveries have highlighted that innate inflammatory cells have bimodal effector functions during the inflammatory response, including active roles during the resolution process. Several mediators displaying potent pro-resolving actions have recently been uncovered. Lipoxin A4, the lead member of this new class of pro-resolving mediators, has anti-inflammatory actions on type 2 innate lymphoid cells and pro-resolving actions through natural killer cells in asthma immunobiology. Eosinophils are also able to control crucial aspects of resolution through the generation of pro-resolving mediators. Uncontrolled asthma has been associated with a defect in the generation of specialised pro-resolving mediators, including lipoxin A4 and protectin D1. Thus, bioactive stable analogue mimetics of these mediators that can harness endogenous resolution mechanisms for inflammation may offer new therapeutic strategies for asthma and airway inflammation associated diseases.

A new, faster, and safe nasal provocation test method for diagnosing mite allergic rhinitis

BACKGROUND

Diagnosing house dust mite (HDM) allergic rhinitis is difficult. The nasal provocation test (NPT) has been shown to be the most pertinent, but several methods are available. According to guidelines, the NPT requires a skin end-point titration and an objective measurement of nasal patency. Hence, NPT is time consuming and its use is limited.

OBJECTIVE

To evaluate the sensitivity, specificity, and safety of a new, more rapid, and simple alternative NPT (NPT-R) to HDM.

METHODS

Eighty-eight patients with from rhinitis (49 allergic to HDM and 39 controls with and without atopy) were included. Allergic rhinitis to HDM was confirmed by a "classic" NPT based on the Lebel score and rhinomanometry. After a period of 4 weeks, NPT-R was performed and only the clinical score was measured.

RESULTS

The study population was young (mean ± SD, 27.7 ± 8.5 years old), composed mostly of women (61 vs 27 men), and 24% reported asthma. The sensitivity and specificity of NPT-R were 83.7% and 100%, respectively. The correlation between the NPTs was statistically significant (0.833, P < .0001, n = 88) and the 2 NPTs were completely safe. Performing NPT-R was more rapid (mean ± SD, 22 ± 8 minutes) than the classic NPT (97 ± 20 minutes).

CONCLUSION

The NPT-R is safe and easier and faster than the classic NPT. This new method appears to be a very useful tool in the diagnosis of HDM allergic rhinitis when the diagnosis is uncertain or before initiating immunotherapy.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT01485523.

Lipoxin A4 regulates natural killer cell and type 2 innate lymphoid cell activation in asthma

Asthma is a prevalent disease of chronic inflammation in which endogenous counterregulatory signaling pathways are dysregulated. Recent evidence suggests that innate lymphoid cells (ILCs), including natural killer (NK) cells and type 2 ILCs (ILC2s), can participate in the regulation of allergic airway responses, in particular airway mucosal inflammation. We have identified both NK cells and ILC2s in human lung and peripheral blood in healthy and asthmatic subjects. NK cells were highly activated in severe asthma, were linked to eosinophilia, and interacted with autologous eosinophils to promote their apoptosis. ILC2s generated antigen-independent interleukin-13 (IL-13) in response to the mast cell product prostaglandin D2 alone and in a synergistic manner with the airway epithelial cytokines IL-25 and IL-33. Both NK cells and ILC2s expressed the pro-resolving ALX/FPR2 receptors. Lipoxin A4, a natural pro-resolving ligand for ALX/FPR2 receptors, significantly increased NK cell-mediated eosinophil apoptosis and decreased IL-13 release by ILC2s. Together, these findings indicate that ILCs are targets for lipoxin A4 to decrease airway inflammation and mediate the catabasis of eosinophilic inflammation. Because lipoxin A4 generation is decreased in severe asthma, these findings also implicate unrestrained ILC activation in asthma pathobiology.

[Pathophysiology of multiple chemical sensitivity]

INTRODUCTION AND BACKGROUND

Multiple chemical sensitivity (MCS) is a complex clinical entity that includes a large number of non-specific symptoms, associated in a univocal manner in each patient and triggered by exposure to various chemicals at low concentrations, well below those known to cause toxic effects. However, no objective test exists currently to diagnose this syndrome. One of the main reasons is that the pathophysiology is poorly understood. However, many explanatory hypotheses have been proposed.

VIEWPOINTS AND CONCLUSIONS

Patients with symptoms of MCS are often encountered by pulmonologists. Their suffering is undeniable but, unfortunately, the lack of understanding of the pathophysiological mechanisms makes treatment difficult and empirical.

Indoor dust and air concentrations of endotoxin in urban and rural environments

SIGNIFICANCE AND IMPACT OF THE STUDY

Rural dairy farming is associated with high exposure to indoor endotoxins as compared to rural nonfarming houses and urban houses. The time spent on the mattress (7 h for an adult) and of the proximity of the contaminated source should be taken into account with the other causes of exposure. Studies in European children from a farming background have shown that these children have a reduced risk of asthma and atopic sensitization compared to their urban counterparts. It has been suggested that this might be due to exposure to high levels of endotoxin in the farming environment. The aim of this study was to compare indoor endotoxin concentrations in air and dust samples from randomly selected urban and rural dwellings. In the rural area, endotoxins were analysed in farmhouses and nonfarmhouses as well as housing characteristics, lifestyle factors and agricultural practices likely to influence air and dust endotoxin levels. Endotoxin levels were significantly higher in floor (6600 ± 6100 vs 3600 ± 5600 and 3800 ± 17,000 ng g⁻¹; P < 0·001) and mattress dust (2900 ± 4100 vs 1100 ± 2400 and 800 ± 2600 ng g⁻¹; P < 0·001) from farmhouses compared to other rural and urban homes. However, no difference was observed between endotoxin concentrations in the air of urban and rural houses, and airborne endotoxin levels did not correlate to dust levels. Lack of ventilation and direct entry into the house were correlated with an increase in dust endotoxin levels. These results confirm that dairy farming is associated with high exposure to endotoxins in indoor dust samples. No difference was observed between indoor airborne concentrations between urban and rural houses. These results suggest that measuring endotoxin in dust is the most relevant method to assess endotoxin exposure.

Nonallergic airway hyperresponsiveness and allergen-specific IgE levels are the main determinants of the early and late asthmatic response to allergen

BACKGROUND

Conflicting results have been reported in studies of predictive factors for airway responsiveness to allergens during bronchial challenges.

OBJECTIVE

The aim of this study was to assess determinants of airway responsiveness to 3 different allergens during standardized bronchial challenges.

METHODS

Data were collected from asthmatic patients who participated in allergen challenge trials between 2000 and 2006 (cat, n = 37; house dust mite [HDM], n = 35; grass pollen, n = 27). PD20 (provocative dose causing a 20% fall in forced expiratory volume in the first second) methacholine, PD20 allergen, allergen skin test endpoint, allergen-specific immunoglobulin (Ig) E levels, and late asthmatic response were analyzed for each allergen group.

RESULTS

During the early asthmatic response, a significant relationship was found between PD20 allergen and PD20 methacholine (P < .01 for cat, HDM, and grass pollen), as well as between PD20 allergen and allergen-specific IgE levels (P < .05 for cat and HDM). No relationship was observed between PD20 allergen and allergen skin test endpoint (P > .05). Late asthmatic response was significantly more frequent after HDM challenge than after cat or grass pollen challenges (57.1% vs16.2% and 33.3%, P < .01). Dual responders during HDM challenges had significantly higher allergen-specific IgE levels (P < .05) and higher nonallergic airway responsiveness (P < .05).

CONCLUSION

Nonallergic airway hyperresponsiveness and allergen-specific IgE levels were the main determinants of early and late asthmatic responses. HDM challenges were the most interesting model with regard to the occurrence of late asthmatic response. In contrast to previous publications and to the official statement on standardized challenge testing with sensitizing stimuli, skin sensitivity appears to be a poor predictor of the early asthmatic response.

EAACI consensus statement for investigation of work-related asthma in non-specialized centres

Work-related asthma (WRA) is a relevant problem in several countries, is cause of disability and socioeconomic consequences for both the patient and the society and is probably still underdiagnosed. A correct diagnosis is extremely important to reduce or limit the consequences of the disease. This consensus document was prepared by a EAACI Task Force consisting of an expert panel of allergologists, pneumologists and occupational physicians from different European countries. This document is not intended to address in detail the full diagnostic work-up of WRA, nor to be a formal evidence-based guideline. It is written to provide an operative protocol to allergologists and physicians dealing with asthma useful for identifying the subjects suspected of having WRA to address them to in-depth investigations in a specialized centre. No evidence-based system could be used because of the low grade of evidence of published studies in this area, and instead, 'key messages' or 'suggestions' are provided based on consensus of the expert panel members.

Thoracic manifestations of primary humoral immunodeficiency: a comprehensive review

Humoral immunodeficiencies, which are characterized by defective production of antibodies, are the most common types of primary immunodeficiency. Pulmonary changes are present in as many as 60% of patients with humoral immunodeficiency. Chronic changes and recurrent infections in the respiratory airways are the main causes of morbidity and mortality in those affected by a humoral immunodeficiency. Medical imaging, especially computed tomography (CT), plays a crucial role in the initial detection and characterization of changes and in monitoring the response to therapy. The spectrum of abnormalities seen at thoracic imaging includes noninfectious airway disorders, infections, chronic lung diseases, chronic inflammatory conditions (granulomatosis, interstitial pneumonias), and benign and malignant neoplasms. Recognition of characteristic CT and radiographic features, and correlation of those features with clinical and laboratory findings, are necessary to differentiate between the many possible causes of parenchymal and mediastinal disease seen in patients with primary humoral immunodeficiencies.

Sublingual-swallow immunotherapy with standardized 3-grass pollen extract: a double-blind, placebo-controlled study

BACKGROUND

Sublingual immunotherapy (SLIT) is accepted as a safe and effective route for the treatment of grass pollen allergy, but clarification of its clinical and biological efficacy requires more study.

OBJECTIVE

To evaluate the efficacy, safety, and compliance of SLIT with a standardized 3-grass pollen extract in patients with grass pollen seasonal allergic rhinoconjunctivitis, with or without mild asthma.

METHODS

This multicenter, randomized, double-blind study included 127 patients (aged 12-41 years; mean age, 24.9 years) with grass pollen seasonal allergic rhinoconjunctivitis, with or without mild asthma. They received either SLIT with a high-dose, standardized, 3-grass pollen extract or placebo for 10 months before and during the grass pollen season. The efficacy evaluation compared weekly clinical scores (defined as the sum of the symptom score and rescue medication score) to measure rhinoconjunctivitis and asthma for the first 8 weeks of the pollen season. We also evaluated safety and compliance and measured changes in anti-Dactylis specific IgG4 antibody levels.

RESULTS

There was a trend in favor of the study group in the mean adjusted clinical score. The groups were not comparable on inclusion (P = .02): the SLIT group included more subjects with asthma and had a higher mean IgG4 serum level. Additional exploration according to subgroups with and without asthma found that among the patients without asthma, the SLIT group had a significantly better clinical score (P = .045). Anti-Dactylis specific IgG4 levels increased significantly in the SLIT group.

CONCLUSION

SLIT with a standardized, high-dose, 3-grass pollen extract is safe and significantly improves the clinical score in patients with hay fever and without asthma during the pollen season.