Quitting smoking does not prevent changes in the immune system caused by smoking.
To acquaintances carcinogenic effects and other health damage caused by smokea study carried out by the Pasteur Institute added that Smoking changes the human defense system and that this change persists long after the habit has been given up. The results were published in the latest issue of the journal. Nature.
Team led Darragh Duffy And Violaine Saint-André, from the French institute studied the influence of 136 environmental factors on the variability of immune responses in blood samples from 1,000 people.
The authors specifically considered cytokine secretionproteins that are released when the body encounters a pathogen and regulate the body’s inflammatory responses.
The work is part of an effort to determine why immune responses vary so much from person to person. In addition to tobacco, the study found that higher levels body mass index previous infection with a usually benign virus (cytomegalovirus) also affects the immune response.
Among the environmental factors studied, smoking had the greatest effect on immune responses. It affects both innate and adaptive immunity: the first is a general response, and the second is more specialized and specific to the pathogen.
Although the effects on innate immune responses were temporary, the effects on adaptive immune responses persisted for years after smoking cessation.
Although the effects on innate responses, such as increased inflammation, were temporary and disappeared after smoking cessation, the effects of the adaptive response persisted for years after smoking cessation, altering blood levels of smoking. cytokines released by infection or other immune problems.
As Violaine Saint-André, the first signatory and co-author of the study, explains to SINC, “Immune responses vary between individuals: the same immune stimulus can cause different responses. Some people develop severe symptoms, while others remain asymptomatic. We see this with SARS-CoV-2 infection and it is mainly due to age, gender and geneticsbut environmental factors such as Life style “They may also contribute to this variability, as we demonstrated in our study.”
In particular, this computational biologist emphasizes that her research shows that “smoking short term effects on innate immunity, with increased levels of the cytokine CXCL5 in smokers compared to non-smokers. “We did not identify any cellular mediation of this mechanism, but rather an association with CEACAM6, which is a blood-soluble protein involved in inflammatory processes and which has been proposed as a clinical biomarker for multiple cancers.”
Long-term effects on adaptive immunity are consistent with increased cytokine levels in smokers and ex-smokers. They are also related to the number of B lymphocytes and regulatory T lymphocytes.
Violaine Saint-André
— Co-author – Pasteur Institute
Concerning long term consequences Regarding adaptive immunity, Saint-André points out that “they correspond to increased levels of the cytokines IL2 and IL13 in smokers and ex-smokers compared to non-smokers. These levels are related to the amount B lymphocytes and T lymphocytes regulators and epigenetic changes”
In fact, he notes, “we observed that the effect of smoking on cytokine levels after T cell stimulation is associated with DNA methylation levels near genes that encode signal transactivators or metabolic regulators.”
Gene methylation
Saint-André notes that they found “more methylation in the genes of current and former smokers compared to those who did not smoke. This correlates with how many years have people smoked And number of cigarettes. After cessation of consumption, methylation around these genes is restored, but this may take several decades,” he emphasizes.
This indicates that the original study design “consisted of a cohort having homogeneous genetic origin detect these genetic associations to the greatest extent possible and, by limiting genetic diversity, be better able to detect environmental impacts.”
The author tells SINC that they are now conducting a 10-year longitudinal study with the same cohort. “Ten years later, we will be able to obtain blood samples from 415 of the original 1,000 people and study the evolution of their immune responses over time, depending on the various changes or pathologies they experienced,” he notes.
The team is repeating the study with another 1,000 people in Hong Kong to compare results between people with different genetic backgrounds and different sociocultural habits.
In addition, the team is reproducing “in collaboration with the Pasteur network a study of an additional 1,000 people in Hong Kong to compare results between people of different genetic backgrounds and different sociocultural habits,” he emphasizes.
As for the implications her work could have for public health, Violaine Saint-André says the study makes a case for the long-term effects of smoking. “This message for people who smoke to quit as soon as possible. This is further evidence of the health impact of this habit and we hope this will help prevent it,” he concludes.
Link: D. Duffy, V. St. André and others – “Smoking alters adaptive immunity with lasting effects.” Magazine Nature, 2023 | DOI: 10.1038/s41586-023-06968-8.