Sputum biomarkers during acute severe asthma attacks in children-a case-control study.

Abstract

To study sputum mediator profiles pattern in children with acute severe asthma, compared with stable asthma and healthy controls. The mechanisms of acute severe asthma attacks, such as biomarkers cascades and immunological responses, are poorly understood. We conducted a prospective observational case-control study of children aged 5 to 17years, who presented to hospital with an asthma attack. Children with stable asthma were recruited during outpatient asthma clinic visits. Control children without an asthma diagnosis were recruited from surgical wards. Sputum mediator profiles were measured, and sputum leukocyte differential cell counts were generated. Sputum data were available in 48 children (acute asthma; n=18, stable asthma; n=17, healthy controls; n=13). Acute-phase biomarkers and neutrophil attractants such as IL-6 and its receptor, IL-8 and cytokines linked with bacterial signals, including TNF-R1 and TNF-R2, were elevated in asthma attacks versus stable asthma and healthy controls. T-cell attractant cytokines, associated with viral infections, such as CCL-5, CXCL-10 and CXCL-11, and CXCL-9 (secreted from eosinophils after a viral trigger) were also raised. Mediator profiles consistent with bacterial and viral respiratory infections, and T2 inflammation markers co-exist in the sputum of children with acute severe asthma attacks.