april 2020 • Journal of Allergy and Clinical Immunology

Association of respiratory allergy, asthma, and expression of the SARS-CoV-2 receptor ACE2

Daniel J. Jackson, William W. Busse, Leonard B. Bacharier, et al.

DOI: 10.1016/j.jaci.2020.04.009

Content curated by::Tiago Rama

Key message

As infecções víricas são causas frequentes de exacerbações de asma. Por esta razão, inicialmente, assumiu-se que a asma deveria ser considerada como factor de risco para doença grave por SARS-COV-2. Este vírus invade as células através da enzima conversora da angiotensina II (ECA2). Nesta carta ao editor, que reflete estudos de quantificação de RNA em 3 coortes distintas, os autores demonstraram que as células epiteliais das vias aéreas de doentes com asma e, ou rinite alérgicas expressam menos ECA2, quando comparados com doentes com asma não alérgica, ou com indivíduos sem asma e sem sensibilização alérgica. Por outro lado, salientam que a expressão de ECA2 diminui após exposição aos alergénios a que os doentes estão sensibilizados. Conclui-se que a aparente reduzida prevalência de asma nas diversas séries de casos de COVID-19 pode resultar de uma menor expressão de ECA2, que se verifica nestes doentes.

Abstract

The novel coronavirus SARS-CoV-2 (COVID-19) was recognized in December 2019 as a cause of severe pneumonia and has now led to a global pandemic.Respiratory illnesses caused by COVID-19 cover a range of severity. The identification of risk and protective factors for disease severity from COVID-19 is critical to direct development of new treatments and infection prevention strategies. Early large case series haveidentified a number of risk factors for severe disease, including older age, hypertension, diabetes, cardiovascular disease, tobacco exposure, and chronic obstructive pulmonary disease.The US Centers for Disease Control and Prevention lists asthma as a risk factor for severe COVID-19 illness, which is logical given that many respiratory viruses have been well established to cause more serious illnesses in those withchronic airway diseases such as asthma. However, asthma and respiratory allergy have not been identified as significant risk factors for severe COVID-19 illness in case series from China. These preliminary reports led us to question whether we could identify features of allergy and/or asthma that could be associated with potential for reduced severity of COVID-19 illness.