Hidden herpes virus reactivation in the lung of asthma: a new potential marker of severity and exacerbation of asthma

Published online: March 20, 2021

Viruses are believed to play important roles in the development and exacerbation of asthma. However, the presence or alteration of the commensal airway viral flora and their roles in asthma are not clearly understood. Virome refers to a collection of all viruses in and on the human body, which constitutes a large part of the human microbiome. Recently, virome studies demonstrated that the viral flora might be a critical factor in host health and diseases. However, the virome has not been extensively studied because of the technical challenges involved in virome experiments and analyses.

In a recent research article in The Journal of Allergy and Clinical Immunology (JACI), Choi et al. successfully characterized the airway virome. They uncovered its relationships with asthma morbidity and exacerbation using induced sputum from healthy participants (n=12) and asthma patients (non-severe, n=15; severe, n=15). To analyze the viral and bacterial composition in the lung, the mixture of DNA/RNAs were sequenced using metagenomics techniques.

Choi et al. found a striking difference in the composition of the lung virome between healthy controls and asthmatic patients. While bacteriophages were the most abundant viruses in the healthy controls, herpesviruses accounted for the majority of airway commensal viruses in the asthma group. Specifically, the two herpesvirus species, cytomegalovirus (CMV) and Epstein-Barr virus (EBV), were most abundant in the severe asthma group up to 10-fold higher abundancies than those in the healthy group. In addition, the abundance of these herpesviruses was nicely correlated with asthma exacerbation and reduced lung function. In contrast to the virome difference, no striking difference was observed in the bacterial composition between healthy controls and asthma patients.

In summary, alteration of airway commensal viruses in asthma patients was evident and reflected the severity and exacerbation of asthma. These findings suggest that the reactivation of human herpesvirus in the lungs could be considered as a new potential biomarker of severity and exacerbation in asthmatic patients.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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