Comparative features of eosinophilic and non‐eosinophilic asthma

Abstract

To the Editor, Studies looking specifically at the prevalence of eosinophilic phenotypes in mild asthma are required. In patients with corticosteroidnaïve asthma, we reported that high eosinophil counts do not necessarily translate into clinical symptoms or lower lung function. 1 However, in asthma of all severities, eosinophils are linked to the worst outcomes. 2 As such, early identification of mild/very mild asthma patients with significant eosinophilia could be a marker of increased risk of such events to modulate therapeutic intervention.This study aimed to compare the features of eosinophilic and non-eosinophilic asthma in patients with asthma of various severities and compare the characteristics of patients according to the intensity of eosinophilia. We hypothesized that patients with an eosinophilic phenotype would demonstrate a more active form of the disease, regardless of its severity.We conducted a retrospective, cross-sectional study based on data from subjects included in the Quebec Heart and Lung Institute-Laval University asthma databank between March 1999 and June 2017. All subjects enrolled for participation in research studies on asthma pathophysiology or treatment, or attending the asthma out-

A clustering analysis of eosinophilic asthmatics: Two clusters with sharp differences in atopic status and disease severity

“…3 While eosinophils are usually thought to be potent inflammatory cells and active contributors to asthma severity, some authors have suggested that lung tissue may actually harbour a population of regulatory eosinophils, the function of which might be to dampen airway inflammation. 4 A recent study has highlighted the existence of a group of patients with mild asthma and high sputum eosinophil count 5 questioning the detrimental action of eosinophils in shaping disease severity and perhaps suggesting heterogeneity in their functional roles.…”

Interleukin‐33 increases type 2 innate lymphoid cell count and their activation in eosinophilic asthma

“…Patients with EA exhibit worse symptoms than those with non-EA (non-eosinophilic asthma (NEA)), regardless of asthma severity. 1 Recent studies have confirmed the crucial involvement of innate lymphoid cells (ILC2s), a rare group of lymphocytes, in innate immune responses to allergic diseases. 2 Innate lymphoid cells lack antigen recognition receptors and produce IL-13 and IL-5, both of which are involved in EA pathogenesis.…”

“…Asthma, a prevalent chronic airway illness, is classified into the eosinophilic asthma (EA), neutrophilic asthma, mixed asthma, and paucigranulocytic asthma based on the counts of eosinophils and neutrophils in the sputum. Patients with EA exhibit worse symptoms than those with non‐EA (non‐eosinophilic asthma (NEA)), regardless of asthma severity 1 . Recent studies have confirmed the crucial involvement of innate lymphoid cells (ILC2s), a rare group of lymphocytes, in innate immune responses to allergic diseases 2 …”