Immunological and pathological effects of electronic cigarettes

Electronic cigarettes (E‐cigarettes) are considered a preferable alternative to conventional cigarettes due to the lack of combustion and the absence of tobacco‐specific toxicants. E‐cigarettes have rapidly gained in popularity in recent years amongst both existing smokers and previous non‐smokers. However, a growing literature demonstrates that E‐cigarettes are not as safe as generally believed. Here, we discuss the immunological, and other, deleterious effects of E‐cigarettes on a variety of cell types and host defence mechanisms in humans and in murine models. We review not only the effects of complete E‐cigarette liquids, but also each of the main components—nicotine, humectants and flavourings. This MiniReview thus highlights the possible role of E‐cigarettes in the pathogenesis of disease and raises awareness of the potential harm that E‐cigarettes may cause.