The negative effect of smoking on the immune system remains for years after the last cigarette, in people who make the big (right) decision to stop this harmful habit. This was shown by a study of the immune response of 1,000 people which was published in the scientific journal “Nature”.
The remaining factors that affect immunity in the long term
The new large-scale analysis is part of an effort by scientists to determine why the immune response varies so much between different people. Based on the findings, in addition to smoking, the main factors that seemed to “mark” the immune system for a long time were a high Body Mass Index as well as a previous infection with a generally “innocent” virus, the cytomegalovirus.
Large differences between different individuals
The COVID-19 pandemic has demonstrated starkly how different people can have different immune responses to the same virus – some people became and are still severely ill while
some others show no symptoms. Previous studies have shown that gender, genetic background and age explain to some extent these differences in immune response, but until now the role of other parameters has not been fully elucidated.
The study
Computational biologist Violène Saint-André from the Institut Pasteur in Paris and her colleagues analyzed blood samples and questionnaires collected by the Milieu Intérieur consortium from 1,000 healthy people living in Brittany, France. The researchers exposed the blood samples to molecules, bacteria and viruses known to activate the immune system. They then measured the effect of each molecule separately on the production of cytokines, proteins that regulate the body’s inflammatory response.
The scientists combined these results with information on 136 demographic, environmental and clinical characteristics of each volunteer. They found that three characteristics were most strongly associated with cytokine response: smoking, BMI, and prior cytomegalovirus infection.
Strong effect on cytokines
The smoking data were particularly strong: this is because the effect of smoking on cytokines was as great as that of age, gender and genetic background. And in fact, this effect appeared to last for years after quitting smoking.
The “puzzle” of personalized medicine is complex
It was even remarkable that individual environmental factors affected different cytokines to a different degree. This suggests that the puzzle of targeted therapies and personalized medicine is even more complex than we think.
“Opening” of the study
In any case, these findings need to be replicated to ensure that the conclusions drawn can be generalized, noted Dr. Saint-Andre. For this reason, it is necessary to “open” the “reservoir” of participants to include more ethnic and racial groups. Already the research team has expanded their study to include volunteers from Senegal and Hong Kong. At the same time, he has collected new blood samples from 415 volunteers of the original study 10 years after it began to analyze the immune response over time.
#Smoking #marks #immune #system #years #quitting
