Viral infections and asthma: an inflammatory interface?

Abstract

Asthma is a chronic inflammatory disease of the airways in which the majority of patients respond to treatment with corticosteroids and b 2 -adrenoceptor agonists. Acute exacerbations of asthma substantially contribute to disease morbidity, mortality and healthcare costs, and are not restricted to patients who are not compliant with their treatment regimens. Given that respiratory viral infections are the principal cause of asthma exacerbations, this review article will explore the relationship between viral infections and asthma, and will put forward hypotheses as to why virus-induced exacerbations occur. Potential mechanisms that may explain why current therapeutics do not fully inhibit virus-induced exacerbations, for example, b 2 -adrenergic desensitisation and corticosteroid insensitivity, are explored, as well as which aspects of virus-induced inflammation are likely to be attenuated by current therapy. @ERSpublications Why do virus-induced asthma exacerbations occur? Mechanisms and interventions

Inhaled corticosteroids and COVID-19: a systematic review and clinical perspective

“…In vitro models suggest that there is impaired interferon production and other antiviral innate immune responses to experimental rhinovirus and influenza infection in both asthma and COPD, and this could potentially increase susceptibility to viral infections including COVID-19. However, not all studies have replicated these findings [3]. For instance, a study of the response of asthmatic children to natural colds, including some due to coronavirus, showed an appropriate innate response [4].…”

“…Therefore, the use of ICS must either reduce the risk of becoming infected or modify the subsequent inflammatory response and lung damage. In vitro, corticosteroids inhibit rhinovirus and respiratory syncytial virus-induced cytokine release [3] but the timing of exposure to ICS appears important with pre-treatment less effective than administration at the time of infection [23].…”

Effect of enterovirus infections on asthma in young children: A national cohort study

“…Moreover, the risk of incident asthma was higher in patients with a higher frequency of admission. The damage caused by EV infection was reported to aggravate chronic inflammation in the airway among infants and young children, thus contributing to the development of incident asthma among these patients. Moreover, the seroprevalence of the EV71 IgE Ab is increased in patients with asthma, supporting this finding.…”

Respiratory Viral Infections in Exacerbation of Chronic Airway Inflammatory Diseases: Novel Mechanisms and Insights From the Upper Airway Epithelium

“…Rhinovirus (RV) and respiratory syncytial virus (RSV) are the predominant viruses linked to the development and exacerbation of chronic airway inflammatory diseases (Jartti and Gern, 2017). Other viruses such as parainfluenza virus (PIV), influenza virus (IFV) and adenovirus (AdV) have also been implicated in acute exacerbations but to a much lesser extent (Johnston et al, 2005;Oliver et al, 2014;Ko et al, 2019). More recently, other viruses including bocavirus (BoV), human metapneumovirus (HMPV), certain coronavirus (CoV) strains, a specific enterovirus (EV) strain EV-D68, human cytomegalovirus (hCMV) and herpes simplex virus (HSV) have been reported as contributing to acute exacerbations .…”