Relationship between longitudinal changes in type-2 inflammation and clinical outcomes in young asthmatics

Abstract

<b>Background:</b> Asthma biomarkers may be of advantage in diagnosis and therapy monitoring. However the changes in asthma biomarkers over time has not been extensively investigated. <b>Aim:</b> To study longitudinal changes in inflammatory biomarkers and clinical outcomes, and the association of these changes, in young asthmatics. <b>Methods:</b> Asthmatics ( age 10-35, n=253) were examined at baseline and follow-up visit, 43 [23-65] median [range] months later. Subjects were analysed using the multi-allergen tests Phadiatop and fx5 (ImmunoCAP) and grouped based on IgE-concentration at baseline: &lt; 0.10, 0.10-0.34 and ≥ 0.35 kU_A/L.&nbsp;The relationship between changes (Δ values) in type-2 biomarkers ( individualized fraction of exhaled NO (FeNO%), blood eosinophil (B-Eos) count), and lung function (% of predicted FEV₁ and FEV₁/FVC) and Asthma Control Test (ACT) score were determined. <b>Results:</b> At follow-up, FEV₁ and FEV₁/FVC had decreased (93.6% vs. 95.8% and 93.4% vs. 94.7% of predicted respectively, (p&lt;0.001 both), whereas ACT score had increased (21.6 vs. 20.6, p=0.001). A significant decline in lung function was seen in subjects with IgE ≥ 0.1 kU_A/L, but not in&nbsp;those with undetectable IgE below 0.10 kU_A/L. In univariate analysis, significant negative correlations between ΔB-Eos count and FeNO% and lung function was seen, but multivariate analysis showed and independent relationship only between ΔFeNO% and both ΔFEV₁ (p&lt;0.05) and ΔFEV₁/FVC (p&lt;0.01). <b>Conclusion:</b> Clinically relevant associations between longitudinal changes in lung function and individualized FeNO were found in young asthmatics. A lung function decline was seen only in patients with detectable IgE-antibody level&nbsp;at baseline.