even after quitting, cigarettes affect the immune system, study finds

A study by the Pasteur Institute shows that cigarettes alter immunity in the long term, even after weaning.

Numerous studies have already proven that smoking impairs the immune system. In other words, when a person smokes, their protection mechanisms, in the event of infection, are less effective than when they do not smoke. This is called the inflammatory response. Smoking weakens this reaction, which can therefore lead to complications in the event of illness, or more aggressive symptoms. Immunity, called innate, is impaired and when a smoker stops smoking, this innate immunity, present from birth, returns to normal fairly quickly.

The other side of our defense system is adaptive immunity, which develops more slowly over the course of life. It is the one that remembers the pathogens that have already affected the body, which allows a faster defense reaction. According to the Institut Pasteur study published in the journal Nature, Wednesday February 14, smoking alters this adaptive immunity in the long term, for 10 to 15 years, after stopping smoking, according to the researchers’ hypothesis. . It affects the way certain genes are expressed, but also T lymphocytes, these key cells in the immune response.

All ages affected

The researchers reached this conclusion, thanks to a group of 1,000 people followed since 2011, aged 20 to 70. Their blood samples were analyzed and exposed to a wide diversity of microbes. The scientists were able to analyze cytokines, these molecules which act as messengers for cells of the immune system.

The researchers’ goal was to explain why defense systems vary so much from one individual to another. Smoking in addition to sex or age is therefore an explanatory factor, but it is obviously not the only one. Two other variables can affect the immune system. These are body mass index and being affected by cytomegalovirus, a virus belonging to the herpes family.