Relationship between longitudinal changes in type‐2 inflammation, immunoglobulin E sensitization, and clinical outcomes in young asthmatics

Abstract

Background Asthma is a heterogeneous condition where biomarkers may be of considerable advantage in diagnosis and therapy monitoring. However, the changes in asthma biomarkers and immunoglobulin E (IgE) over the course of life has not been extensively investigated. Objective To study longitudinal changes in type‐2 inflammatory biomarkers, IgE, and clinical outcomes, and the association between these changes, in young asthmatics. Methods Asthmatics (age 10–35 years, n = 253) were examined at baseline and at a follow‐up visit, 43 [23–65] (median [range]) months later. Subjects were analyzed using the multi‐allergen tests Phadiatop and fx5 (ImmunoCAP) and grouped based on the baseline allergen‐specific IgE antibody (sIgE) concentration: <0.10, 0.10–0.34, and ≥0.35 kUA/L. The relationship between changes (Δ values) in type‐2 biomarkers (individualized fraction of exhaled nitric oxide [FeNO%], blood eosinophil [B‐Eos] count, total IgE [tIgE] and sIgE, lung function [% predicted forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC)], and Asthma Control Test [ACT]) score were determined. Results At follow up, FEV1 and FEV1/FVC had decreased (93.6% vs. 95.8%, and 93.4% vs. 94.7% of predicted, respectively [p < 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 sIgE ≥ 0.10 kUA/L, but not in those with undetectable sIgE (<0.10 kUA/L). Furthermore, tIgE and sIgE declined over time (p < 0.001 all) whereas FeNO% and B‐Eos count were not significantly changed. In univariate analysis, significant negative correlations between ∆B‐Eos count and ∆FeNO%, on one hand, and changes in lung function, on the other hand, were seen, and multivariate analysis showed an independent relationship between ΔFeNO%, and ΔFEV1 (p < 0.05) and ΔFEV1/FVC% (p < 0.01). Sex‐specific analysis showed that the independent association between ΔFeNO%, and ΔFEV1 remained only in females (p = 0.005), and there was a significant interaction with sex (p = 0.02). Conclusion In young asthmatics, IgE levels declined over 43 months, whereas FeNO and B‐Eos remained unchanged. In spite of improved asthma control, an accelerated lung function decline was seen in patients with detectable sIgE at baseline, and the decline correlated with changes in type‐2 biomarkers. Particularly, the increase in individualized FeNO associated independently with decline in FEV1 in females.

Probiotics in Children with Asthma

“…These events result from type-2 immune response [ 75 ]. Therefore, it is important to take preventive measures aimed at restoring a physiological immune response [ 76 ].…”

Phenotyping, Precision Medicine, and Asthma

“…63 A paucity of literature examining the longitudinal predictive value of IgE exists, with asthma control studies showing mixed results. 64,65 In addition, total IgE levels have not been shown to predict response to IgE targeted therapy making its utility as a singular biomarker questionable. Although upregulation of IgE is undoubtedly a sign of underlying activation of type 2 inflammation, it appears unlikely that serum IgE alone will ever be used as a reliable marker for Th2 inflammation.…”

ERS technical standard: Global Lung Function Initiative reference values for exhaled nitric oxide fraction (FENO50)

“…Unlike other pulmonary function tests, where results are related to population norms and expressed as percent predicted or z scores, FENO50 is usually expressed as high cut-off values (6)(7)(8)(9). Cut-offs are used since population-based studies of 'healthy' individuals consistently show that the distribution of FENO50 values is right-skewed, with significant overlap between the distribution in people with stable or controlled asthma.…”