Expression of circulating angiotensin‐converting enzyme 2 in children with asthma and the effects of inhaled corticosteroids

BACKGROUND: The global spread of coronavirus disease 2019 (COVID‐19) has resulted in a significant disease burden, yet asthma patients do not have the expected high morbidity and mortality rates in the pandemics of COVID‐19. OBJECTIVE: To find the difference of angiotensin‐converting enzyme 2 (ACE2) in asthma and nonasthma children and evaluate the effect of inhaled corticosteroids (ICS) on its expression. METHODS: The ACE2, immunoglobulin E (IgE), and eosinophils were tested in different children. RESULTS: A total of 157 children aged 3–16 years were enrolled. The expression of ACE2 in asthma children were lower than nonasthma children (T = −2.512, p = .013). Allergic nonasthma children had a significant higher ACE2 expression than children with allergic asthma (p = .013) and nonallergic asthma (p = .029). The expression of ACE2 had no significant difference between first‐diagnosed asthma children and that had been treated with ICS for ≥6 months (F = 0.028, p = .598). The allergic asthma children showed a significantly higher eosinophils cells (EC) count than the allergic nonasthma (W = 200, p < .001) and nonallergic nonasthma children (W = 1089, p < .001). Nonallergic asthma children also had a significant higher EC count than the allergic non‐asthma (W = 182.5, p < .001) and nonallergic non‐asthma (W = 200.5, p < .001) children. There was no significant difference in IgE levels between asthmatic children and non‐asthmatic children (W = 2792.5, p = .18). CONCLUSION: Circulating ACE2 levels in asthmatic children were lower than those in non‐asthmatic children and ICS treatment for ≥6 months did not affect the expression of ACE2 in peripheral blood in the asthma children.