2024-04-13 20:19:53
An ingenious experiment, with 1,000 people from the same city analyzed in depth, reveals the unknown persistent effects of smoking
The coronavirus pandemic was a master class in understanding that each person has characteristic defenses against diseases. Some infected did not even realize it and others died in a matter of days. A little over a decade ago, Spanish biologist Lluís Quintana-Murci and his American colleague Matthew Albert began a bold experiment to understand the determining factors of this variability. They recruited 1,000 healthy people between 20 and 70 years old in the French city of Rennes, choosing 100 volunteers of each sex for each decade.
They all provided blood and stool samples and filled out a 44-page questionnaire about their lifestyle. Skin biopsies were even taken to grow their cells in the laboratory. The latest results are presented this Wednesday: smoking is the factor that most alters defenses, even years after having stopped smoking.
There are more than 100 reasons to reject tobacco, according to the count of the World Health Organization: the greater risk of suffering from cancer or a heart attack, bad body odour, the expense (more than 1,800 euros a year for pack-a-day smokers), wrinkles on the face, yellow teeth, damage to people exposed to second-hand smoke.
The president of the Spanish Society of Immunology, Marcos Lopez Hoyos, applauds the new work, in which he has not participated. “In many patients with chronic smoking and COPD (chronic obstructive pulmonary disease) we have always seen a clinical finding: we found hypogammaglobulinemia. [bajos niveles de anticuerpos], which is a cause of secondary immunodeficiency,” he points out. “In COPD with smoking there are more infections and there is more cancer.
The alteration of the cytokines that they have observed clearly indicates that it can favor an alteration in the regulation of the immune response and generate these diseases, although they do not prove it,” says López Hoyos, scientific director of the Marqués de Valdecilla Research Institute, in Santander. “It’s a beautiful experiment,” he celebrates.
The new results are “very interesting, but not surprising,” according to oncologist Alberto Ocaña, who emphasizes his caution. “The study only shows that tobacco alters the immune system, not that these alterations are the cause of cancer. Cancer is a genetic disease that also requires other added alterations, such as a dysfunctional immune system,” explains Ocaña, coordinator of the Experimental Cancer Therapies Unit at the San Carlos Clinical Hospital, in Madrid.
The Pasteur Institute team has grown cells from volunteers, put them in contact with different substances in the laboratory and analyzed how they behave. Immunologist África González, from the University of Vigo, is surprised by the duration of the effect of smoking.
“It is striking that this signature is persistently maintained in the immune system, as if saying: ‘You have smoked.’ And those cells, when they have been exposed to tobacco, are going to behave differently against a pathogen,” he reflects. “They cannot say categorically that this alteration increases your risk of cancer, but tobacco itself not only alters the immune response, but also has many substances that are carcinogenic in themselves,” he warns. González.
Source: El País