Correlation between Serum IL-23 and Pulmonary Functions in a group of Asthmatic Children

Abstract

Background: Bronchial asthma (BA) is a chronic inflammatory airway disease characterized by episodic reversible airway obstruction. BA is classified into T2 high asthmatic endotype with increased Eosinophils (Eos) and Non-T2/T2 low asthmatic endotype with increased Th17 cells and neutrophils. Interleukin-23 (IL-23) has a pivotal role in BA through the maintenance and activation of Th2 and Th17 cells which are contributors to the pathogenesis and severity of BA. Pulmonary function tests (PF) give information about the mechanics of moving air to and from the alveoli through the trachea-bronchial tree in an objective way.

Aim of the work:  to evaluate serum IL-23 levels in asthmatic children compared with healthy controls and to correlate them to PF.

Subjects and methods: A cross-sectional study including 90 children aged from 1 to 12 years old was performed, 50% of children were asthmatic (group 1) and 50% were healthy children serving as a control group (group 2). Asthmatic children were recruited from Allergy and Pulmonology clinic, Children's Specialty Hospital, Cairo University. These patients were divided according to age into 3 subgroups (A, B, and C) with 15 patients in each: (A) those aged between 1- 2.5 years old performed infant PF, (B) those aged between 4- 6 years old performed Impulse Oscillometry (IOS) and (C) those aged between 6- 12 years old performed Spirometry. Clinical data were recorded, and a complete blood picture (CBP) including Absolute Eosinophilic count (Eos), total serum Immunoglobulin E (IgE), and serum IL-23 were performed.

Results: IL-23 was significantly higher in asthmatic children than in controls. In subgroup (A); minute ventilation inversely correlated to total serum IgE but not to IL-23. In subgroup (B), IL-23 was higher in patients with abnormal PF, however, it didn't correlate to any PF parameters. In subgroup (C), IL-23 inversely correlated to each of the following post-bronchodilator parameters: FEV1, MEF50, and MEF75.

Conclusion: Serum IL-23 is high in asthmatic children and it strongly and inversely correlated to some post-bronchodilator PF parameters in asthmatic children aged 6-12 years.