"Comparisons of immune responses in smokers and ex-smokers showed that the inflammatory response quickly returns to normal levels after smoking cessation, and the effects on adaptive immunity persist for 10 to 15 years," Darragh Duffy, head of the Translational Immunology Unit at the Institut Pasteur and the final author of the study, said in a statement. "This is the first time that we have been able to demonstrate the long-term effects of smoking on immune responses."



Smoking appears to cause long-term changes in the immune system by affecting gene expression, the researchers said.

"This is an important discovery that allows us to understand how smoking affects immunity in healthy people, and, for comparison, in people with different diseases," said Violaine Saint-André, a biologist at the Institut Pasteur and the study's lead author.

The scientists noted that further research is needed to identify the protein and gene interactions affected by smoking.

"These results provide new insights into the impact of smoking on human health and the role of modifiable environmental influences on immune response variability," the authors concluded.