Smoking Has Long-Term Effects on the Immune System

Like other factors such as age, sex and genetics, smoking has a major impact on immune responses. 

This is the finding recently made by a team of scientists at the Institut Pasteur using the Milieu Intérieur cohort of 1,000 healthy volunteers, established to understand variability in immune responses. 

In addition to its short-term impact on immunity, smoking also has long-term consequences. For many years after they have quit the habit, smokers are left with effects on some of their bodies’ defense mechanisms acquired while smoking. 

These findings, which for the first time reveal a long-term memory of the effects of smoking on immunity, are published in the journal Nature.

Individuals’ immune systems vary significantly in terms of how effectively they respond to microbial attacks. But how can this variability be explained? What factors cause these differences?  “To answer this key question, we set up the Milieu Intérieur cohort comprising 1,000 healthy individuals aged 20 to 70 in 2011,” comments Darragh Duffy, Head of the Translational Immunology Unit at the Institut Pasteur and last author of the study. 

While certain factors such as age, sex and genetics are known to have a significant impact on the immune system, the aim of this new study was to identify which other factors had the most influence.”

The scientists exposed blood samples taken from individuals in the Milieu Intérieur cohort to a wide variety of microbes (viruses, bacteria, etc.) and observed their immune response by measuring levels of secreted cytokines. 

Using the large quantities of data gathered for individuals in the cohort, the team then determined which of the 136 investigated variables (body mass index, smoking, number of hours’ sleep, exercise, childhood illnesses, vaccinations, living environment, etc.) had the most influence on the immune responses studied. Three variables stood out: smoking, latent cytomegalovirus infection and body mass index. 

As regards smoking, an analysis of the data showed that the inflammatory response, which is immediately triggered by infection with a pathogen, was heightened in smokers, and moreover, the activity of certain cells involved in immune memory was impaired. 

In other words, this study shows that smoking disrupts not only innate immune mechanisms, but also some adaptive immune mechanisms. 

Sources:

Violaine Saint-André, Bruno Charbit, Anne Biton, Vincent Rouilly, Céline Possémé, Anthony Bertrand, Maxime Rotival, Jacob Bergstedt, Etienne Patin, Matthew L. Albert, Lluis Quintana-Murci, Darragh Duffy, Laurent Abel, Andres Alcover, Hugues Aschard, Philippe Bousso, Nollaig Bourke, Petter Brodin, Pierre Bruhns, Nadine Cerf-Bensussan, Ana Cumano, Christophe D’Enfert, Caroline Demangel, Ludovic Deriano, Marie-Agnès Dillies, James Di Santo, Gérard Eberl, Jost Enninga, Jacques Fellay, Ivo Gomperts-Boneca, Milena Hasan, Gunilla Karlsson Hedestam, Serge Hercberg, Molly A. Ingersoll, Olivier Lantz, Rose Anne Kenny, Mickaël Ménager, Frédérique Michel, Hugo Mouquet, Cliona O’Farrelly, Antonio Rausell, Frédéric Rieux-Laucat, Lars Rogge, Magnus Fontes, Anavaj Sakuntabhai, Olivier Schwartz, Benno Schwikowski, Spencer Shorte, Frédéric Tangy, Antoine Toubert, Mathilde Touvier, Marie-Noëlle Ungeheuer, Christophe Zimmer. Smoking changes adaptive immunity with persistent effects. Nature, 2024; DOI: 10.1038/s41586-023-06968-8

Institut Pasteur. (2024, February 14). Smoking has long-term effects on the immune system. ScienceDaily. Retrieved February 15, 2024 from www.sciencedaily.com/releases/2024/02/240214122022.htm

Image from: https://unsplash.com/photos/a-man-smoking-a-cigarette-in-the-dark-wQv94mB3TcY