Smoking May Compromise Immune Health, Even Years After Quitting - Scientific American (No paywall) Numerous factors shape how a person’s immune system reacts to infections and other challenges. Age, sex and genetics are fundamental contributors—as the COVID pandemic highlighted. Now a new study shows that smoking has an equally important impact on certain immune responses, with some of its effects possibly lasting well beyond when a person quits.To explore which environmental factors had the biggest role, researchers measured the production of cytokines—key messenger molecules that mediate inflammation—in the blood of 1,000 healthy people after exposing the samples to either bacteria, fungi, antibodies or other agents known to elicit an immune response. Smoking was found to greatly alter both the innate response—the body’s general and immediate first line of defense—and the slower, more threat-specific adaptive response. The data suggest that the cytokine secretion in the innate immune response rapidly returns to the level of nonsmokers after a person quits smoking but that the effects on the adaptive response appear to endure for years or decades through a process called epigenetic memory. The results were published today in Nature.
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