Biomarkers for severe allergic asthma in children: could they be useful to guide disease control and use of omalizumab?

Management of eosinophil-associated inflammatory diseases: the importance of a multidisciplinary approach

Elevated eosinophil counts in blood and tissue are a feature of many pathological processes. Eosinophils can migrate and accumulate in a wide variety of tissues and, by infiltrating a target organ, can mediate the development of several inflammatory diseases. The normalization of eosinophilia is a common biomarker of a treatable trait and can also be used as a prognostic and predictive biomarker since it implies a reduction in type 2 inflammation that contributes to disease pathogenesis. Biological therapies targeting this cell type and its proinflammatory mediators have been shown to be effective in the management of a number of eosinophilic diseases, and for this reason they constitute a potential common strategy in the treatment of patients with various multimorbidities that present with type 2 inflammation. Various biological options are available that could be used to simultaneously treat multiple target organs with a single drug, bearing in mind the need to offer personalized treatments under the umbrella of precision medicine in all patients with eosinophil-associated diseases (EADs). In addition to reviewing these issues, we also discuss a series of perspectives addressing the management of EAD patients from a multidisciplinary approach, with the collaboration of health professionals from different specialties who manage the different multimorbidities that frequently occur in these patients. We examine the basic principles of care that this multidisciplinary approach must cover and present a multidisciplinary expert opinion regarding the ideal management of patients with EADs, from diagnosis to therapeutic approach and follow-up.

Predictive biomarkers for response to omalizumab in patients with severe allergic asthma: a meta-analysis

BACKGROUND

Predicting omalizumab treatment response has been a challenge and significant aspect for selecting suitable severe allergic asthma patients for omalizumab use.

OBJECTIVE

To determine which domains of pretreatment baseline characteristics predict omalizumab treatment response among asthmatic patients.

METHODS

Electronic bases were searched for eligible studies that reported potential biomarkers that could predict omalizumab responsiveness and efficacy. Patients who accepted omalizumab treatment were stratified into responders and non-responders. WMD, OR, and their 95%CI were used to access the differences between those omalizumab receivers. Sensitivity analysis and subgroup analysis were conducted for potential heterogeneity.

RESULTS

A total of 41 studies evaluating efficacy predictors of omalizumab were included in this meta-analysis. The pooled results showed that omalizumab responders had significantly younger age in the adult subgroup, higher pretreatment total serum IgE level, percent predicted FEV₁ and FeNO than that non-responder. We further confirmed that higher blood eosinophil counts and total serum IgE levels are useful markers for selecting asthma patients who may benefit more from omalizumab.

CONCLUSIONS

Pre-treatment blood eosinophil counts and total serum IgE level can be a useful efficacy predictor in selecting allergic asthma patients for omalizumab treatment.

Blood eosinophil cationic protein and eosinophil-derived neurotoxin are associated with different asthma expression and evolution in adults

BACKGROUND

Eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) are proteins released by activated eosinophils whose role in adult asthma remains unclear.

OBJECTIVE

To study associations between ECP, EDN and various asthma characteristics in adults from the Epidemiological Study on the Genetics and Environment of Asthma (EGEA).

METHODS

Plasma ECP and EDN levels were measured by ELISA. Cross-sectional analyses were performed in 941 adults (43±16 years old, 39% with asthma) at EGEA2 (2003-2007). Longitudinal analyses investigated the associations between EDN level at EGEA2 and changes in asthma characteristics between EGEA2 and EGEA3 (2011-2013, n=817). We used generalised estimated equations adjusted for age, sex, smoking status and body mass index to take into account familial dependence.

RESULTS

At EGEA2, both high ECP and EDN levels were associated with current asthma (adjusted OR (aOR) (95% CI): 1.69 (1.35-2.12) and 2.12 (1.76-2.57)). Among asthmatics, high EDN level was associated with asthma attacks (aOR: 1.50 (1.13-1.99)), wheezing and breathlessness (aOR: 1.38 (1.05-1.80)), use of asthma treatments (aOR: 1.91 (1.37-2.68)) and bronchial hyper-responsiveness (aOR: 2.03 (1.38-2.97)), even after further adjustment on ECP. High ECP level was associated with high neutrophil count and tended to be associated with chronic bronchitis. High EDN level at EGEA2 was associated with persistent asthma (aOR: 1.62 (1.04-2.52)), nocturnal symptoms (aOR from 2.19 to 3.57), worsening wheezing and breathlessness (aOR: 1.97 (1.36-2.85)) and nocturnal shortness of breath (aOR: 1.44 (1.04-1.98)) between EGEA2 and EGEA3.

CONCLUSIONS

EDN and ECP were associated with different asthma expression in adults. EDN could be a potential biomarker to monitor asthma evolution in adults.

A Current Perspective of Allergic Asthma: From Mechanisms to Management

Asthma is a result of heterogenous, complex gene-environment interactions with variable clinical phenotypes, inflammation, and remodeling. It affects more than 330 million of people worldwide throughout their educational and working lives, while exacerbations put a heavy cost/burden on productivity. Childhood asthma is characterized by a predominance of allergic sensitization and multimorbidity, while in adults polysensitization has been positively associated with asthma occurrence. Despite significant improvements in recent decades, asthma management remains challenging. Recently, a group of specialists suggested that the term "asthma" should be preferably used as a descriptive term for symptoms. Moreover, type 2 inflammation has emerged as a pivotal disease mechanism including overlapping endotypes of specific IgE production, while type 2-low asthma includes several disease endotypes. Optimal asthma control requires both appropriate pharmacological interventions, tailored to each patient, as well as trigger avoidance measures. Regular monitoring for maintenance of symptom control, preservation of lung function, and detection of treatment-related adverse effects are warranted. Allergen-specific immunotherapy and the advent of new targeted therapies for patients with difficult to control asthma offer diverse treatment options. The current review summarizes up-to-date knowledge on epidemiology, definitions, diagnosis, and current therapeutic strategies.

Serum ECP as a diagnostic marker for asthma in children less than 5 years: A systematic review and meta-analysis

BACKGROUND

Currently, there are no clear-cut clinical or laboratory parameters to diagnose asthma in young children. Spirometry or the lung function tests cannot be reliably measured in children less than 5 years. The purpose of this study is to evaluate the efficacy of serum eosinophilic cationic protein (sECP) in diagnosing asthma among children less than 5 years of age.

METHODS

A systematic review was performed in PubMed, EMBASE, and Web of Science databases to identify studies investigating the role of sECP in diagnosing childhood asthma. The quality of each study was assessed using quality assessment of diagnostic accuracy studies 2 scale. A meta-analysis was conducted using the RevMan 5.3 application.

RESULTS

A total of eight studies meeting the eligibility criteria were included in the systematic review and five studies in the meta-analysis. There was a degree of clinical heterogeneity between studies primarily related to the definition of asthma and the time of assessment of sECP levels. Pooled sensitivity was 0.79 (95% confidence interval [CI]: 0.66-0.88), pooled specificity was 0.79 (95% CI: 0.54-0.92), and the pooled diagnostic odds ratio was 14.73 (95% CI: 3.58-60.58).

CONCLUSION

Overall, this review found insufficient evidence to support the role of sECP levels in diagnosing early childhood asthma.

The concepts of asthma endotypes and phenotypes to guide current and novel treatment strategies

INTRODUCTION

Asthma, a common, non-communicable chronic disease affects over 300 million individuals worldwide. The Western world lifestyle is claimed to be responsible for this high and increasing prevalence. Asthma has been defined as a syndrome with various phenotypes and endotypes, allergic asthma and type 2 asthma being the most frequent. A great increase in prevalence of allergic diseases has necessitated intensive investigations both for understanding the underlying mechanisms and for the development of novel therapy options with long-term efficacy and limited side-effects. Allergic patients demonstrate unique presentations with variable visible characteristics and disease outcomes depending on different molecular mechanisms, related to influence of genes and epigenetic control by micro- and macro-environment. Areas covered: This article reviews the definition of asthma phenotypes and possible endotypes, advances in allergy-immunology field and contemporary personalized therapy options for asthma. Expert commentary: Better understanding of the complex immune network of allergic inflammation and key players of immunity is continuously being provided for clarification of asthma sub-types. Successful therapy of asthma requires better definition of underlying pathogenesis, which sequentially could end up with 'custom-tailored' individualized, evidence-based and more precise therapy options; a new era termed as 'precision medicine'. Endotype, phenotype, theratype and biomarker terms arise as major keywords in precision/personalized medicine.