Smoking permanently affects the immune system

Smoking permanently affects the immune system

People who smoke have a weaker armor when it comes to dealing with diseases and pathogens. A study conducted by the Pasteur Institute and the University of Oxford and published yesterday in the journal Nature points to smoking as one of the factors most influential on human immune responses. As this analysis reveals, smoking causes some temporary changes in the immune system, and other changes that, on the other hand, can continue even years after quitting the habit. “Tobacco may have as much or greater impact on the immune system than factors such as genetics or age,” suggests the work led by Darragh Duffy and Violin Saint-André.


The research was based on an analysis of 1,000 individuals. As the authors explain, on the one hand, blood samples were collected from volunteers, and on the other hand, information was collected about socio-demographic and environmental variables, such as age, gender, weight, or habits such as smoking. From there, they analyzed blood samples, simulated exposure to various viruses and bacteria in laboratories, and analyzed the secretion of cytokines (proteins released when the body encounters pathogens that play a key role in fighting infection or disease). With all this information, scientists put the pieces of the puzzle together and identified the factors that most influence the functioning of the immune system.

The disruptors

Analyzes point to smoking as one of the main factors that disrupt the immune system. This phenomenon is experienced at different levels. On the one hand, changes have been discovered in the functioning of innate immunity, which is the first barrier that our body creates to deal with external threats. On the other hand, there are also failures in the functioning of adaptive immunity, which relates to our immune system's memory of remembering past infections and creating barriers to avoid future infections. “In people who smoke, the levels of cytokines released change,” scientists say.

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According to the scientists who led this analysis, some changes return to normal after quitting smoking. Especially those related to innate immunity. Those that modify the specific response to certain viruses and bacteria continue to behave in an altered manner even “years after smoking cessation.” In this case, experts say more studies are needed to understand whether these damages to the immune system are permanent or return to normal over time. For now, these findings allow us to understand the extent to which this habit can weaken the armor needed to deal with disease and infection.

The results of this study should help to understand, for example, “why tobacco is an important risk factor in the development of tumors in organs other than the lung,” commented Ignacio J. Molina, professor of immunology at Columbia University. Granada, in statements to the Scientific Media Center portal in Spain.

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