Smoking has long-term effects on the immune system.
- In 2022, France still had nearly 12 million daily smokers.
- Smoking disrupts not only mechanisms of innate immunity but also certain mechanisms of adaptive immunity, according to a new study.
- “This is the first time that we have highlighted the long-term influence of smoking on immune responses,” explains the author.
Smoking has long-term effects on the immune system. This is what a team from the Pasteur Institute has just highlighted, the results of which are published in the journal Nature.
The immune system varies enormously from one individual to another, acting more or less effectively in the face of microbial attacks. How can we explain such variability? What are the factors that induce these differences?
Smoking and the immune system: research methodology
“It is to answer this big question that we set up the Midi Interior cohort in 2011, which brings together 1,000 healthy individuals aged 20 to 70,” begins Darragh Duffy, head of the Translational Immunology unit at the Institut Pasteur and author of the study. “We already know that certain factors such as age, sex or genes have a strong impact on the immune system, but with this new study, we wanted to know which other factors had the most influence”, she adds.
His team therefore exposed blood samples taken from individuals in the Midi Interior cohort to a wide diversity of microbes (viruses, bacteria, etc.) and observed how the immune system reacted by measuring cytokine levels.(1) secreted.
Having a lot of information on the members of the cohort, the team was then able to observe which variables among the 136 retained (body mass index, smoking, number of hours of sleep, physical activity, diseases childhood, vaccinations, place of living, etc.) had the most influence on the immune responses studied.
Three variables then stood out: smoking, latent cytomegalovirus infection(2) and body mass index. “These three factors could have as much influence on certain immune responses as age, sex or genetic variables,” underlines Darragh Duffy.
Effects on the immune system even after stopping smoking
Regarding smoking, data analysis also demonstrated that the activity of certain cells involved in immune memory was altered. In other words, this study shows that smoking not only disrupts mechanisms of innate immunity but also certain mechanisms of adaptive immunity.
“By comparing the immune responses of smokers and ex-smokers, we found that the inflammatory response quickly returned to normal after stopping smoking but that the impact on adaptive immunity persisted over time, that is to say for 10 or 15 years”, reports Darragh Duffy. “This is the first time that we have demonstrated the long-term influence of smoking on immune responses. she continues.
“This is an important discovery to better understand the impact of smoking on the immunity of healthy individuals but also, by comparison, on the immunity of individuals suffering from various pathologies,” concludes Violaine Saint-André.
In 2022, the France still had nearly 12 million daily smokers.
(1) proteins secreted by a large number of immune cells to communicate with each other and participate in immune defenses.
(2) virus, often asymptomatic but dangerous for the fetus, which belongs to the Herpes family.
