ACE2 expression in allergic airway disease may decrease the risk and severity of COVID-19

Abstract

The coronavirus disease (COVID-19) is caused by Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and presents with respiratory symptoms which can be life threatening in severe cases. At the start of the pandemic, allergy, asthma, and chronic obstructive pulmonary disease (COPD) were considered as risk factors for COVID-19 as they tend to exacerbate during respiratory viral infections. Recent literature has not shown that airway allergic diseases is a high-risk factor or that it increases the severity of COVID-19. This is due to a decrease in Angiotensin-converting enzyme 2 (ACE2) gene expression in the nose and bronchial cells of allergic airway diseases. Conventional asthma treatment includes inhaled corticosteroids (ICS), allergen immunotherapy (AIT), and biologics, and should be continued as they might reduce the risks of asthmatics for coronavirus infection by enhancing antiviral defence and alleviating inflammation. Keywords Allergic rhinitis • Asthma • SARS-CoV-2 • COVID-19 • Angiotensin-converting enzyme 2 (ACE2) • Transmembrane protease serine 2 (TMPRSS2) • Inhaled corticosteroids (ICS) • Allergen immunotherapy (AIT)

An Overview of Asthma and COVID-19: Protective Factors Against SARS-COV-2 in Pediatric Patients

“…Many risk factors such as diabetes, obesity and cardiovascular diseases are associated with COVID-19. Surprisingly, despite being a chronic respiratory disease, asthma would not seem a risk factor for COVID-19 either in childhood or in adulthood ( 1 , 2 , 12 ). In this mini-review, we will describe the current literature regarding protective factors against COVID-19 in children with asthma based on the evidence available at this time.…”

“…In the first week following symptoms, the primary antibody response determines an increased amount of virus-specific IgM followed by production of virus-specific IgGs ( 14 ). If the adaptive immune responses are insufficient, innate immune responses can be reinforced through a cytokine storm that is responsible for severe multi-organ damage ( 1 , 2 ). In case of low-dose virus infection, efficient T- and B-cells responses and neutralizing antibodies could lead to rapid viral clearance.…”

“…Asthma remains one of the highest causes for school absence and hospital admissions, imposing a high socioeconomic burden, and impairing quality of life of children and their families ( 16 , 17 ). Allergic asthma is the most common type, where exposure to allergens in sensitized subjects specifically triggers a type 2 (T2) inflammatory response ( 1 , 2 ). Because of the tendency for disease exacerbation elicited by common respiratory viruses including Rhinovirus, Respiratory Syncytial Virus, Influenza virus, Parainfluenza virus, Adenovirus, human Bocavirus, and Coronaviruses ( 18 ) and a deficient antiviral immune response that is evident in asthmatic patients ( 2 , 19 , 20 ), the latter should potentially have increased vulnerability to SARS-COV-2 infection.…”

“…Coronaviruses are a family of single-stranded RiboNucleoid Acid (RNA) viruses able to infect humans, other mammals, and avian species. Human coronaviruses usually cause seasonal and mild respiratory tract infections which spread predominantly by droplets, aerosols and contact transmission, even though severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2, which have appeared over the past 20 years, are considered highly pathogenic ( 1 , 2 ). The infection caused by SARS-CoV-2, also recognized as Coronavirus Disease 2019 (COVID-19), began in Wuhan (China) and quickly spread all over the globe, so that this outbreak was proclaimed a pandemic on March 11, 2020, by the World Health Organization ( 3 ).…”

“…The infection caused by SARS-CoV-2, also recognized as Coronavirus Disease 2019 (COVID-19), began in Wuhan (China) and quickly spread all over the globe, so that this outbreak was proclaimed a pandemic on March 11, 2020, by the World Health Organization ( 3 ). COVID-19 presents with general and respiratory symptoms (fever associated with fatigue, myalgia, anorexia, dry cough, dyspnea), from mild to severe, which can be associated with a so-called “cytokine storm” ( 1 , 2 ). Indeed, some patients show fast progression of the disease, ending in acute lung damage and multiple organ failure, whereas many infected people show mild or no symptoms.…”