Electronic-Cigarette Use alters Nasal Mucosal Immune Response to Live-attenuated Influenza Virus.

Introduction:
This article presents the results of a clinical trial examining the impact of electronic cigarette (e-cigarette) use on the nasal mucosal immune response to live-attenuated influenza virus (LaIV) inoculation. The trial compares viral load, immune-mediator gene expression and protein levels, and nasal mucosal antibody production among three groups of young adults: nonsmokers, smokers, and e-cigarette users.

Key Points:

* The study found that e-cigarette use altered nasal LaIV-induced immune responses, including gene expression, cytokine and chemokine release, and LaIV-specific Iga levels.
* There were no significant differences in viral load among the three groups, but LaIV-induced gene-expression changes in nasal biopsy specimens differed in cigarette smokers and e-cigarette users as compared with nonsmokers, with a greater number of genes changed in e-cigarette users, mostly resulting in decreased expression.
* The top downregulated genes in cigarette smokers were SMPD3, NOS2a, and KLRB1, and the top downregulated genes in e-cigarette users were MR1, NT5E, and hRaS.
* LaIV-induced cytokine levels in nasal epithelial-lining fluid differed among the three groups, including decreased antiviral host-defense mediators (IFN g, IL6, and IL12p40).
* Sex interacted with tobacco-product exposure to modify LaIV-induced immune-gene expression.
* The study suggests that e-cigarette use could increase the risk of suppressed host-defense functions in the context of respiratory viral infections, with important public health implications during influenza season and respiratory-virus pandemics.

Main Message:
The study highlights the potential risks associated with e-cigarette use, particularly in the context of respiratory viral infections. The findings suggest that e-cigarette use may impair the nasal mucosal immune response, potentially increasing the risk of respiratory infections and their severity. The results underscore the importance of continued research into the health effects of e-cigarette use and the need for appropriate regulatory measures to protect public health.

Rebuli ME, Glista-Baker E, hoffman JR, et al. Electronic-Cigarette Use alters Nasal Mucosal Immune Response to Live-attenuated Influenza Virus. a Clinical Trial. american journal of respiratory cell and molecular biology. 2021;64(1):126-137. doi:10.1165/rcmb.2020-0164OC