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According to an American study, people reaching the age of 100 and over have one thing in common: a unique immunity that helps them achieve this exceptional longevity.
What is the secret of people who blow out a hundred candles? The answer lies with their immune system, according to a new study conducted in Boston and published March 31 in the journal Lancet eBiomedicine.
Is the secret of centenarians to be found in their immune system?
The team of researchers from Boston University Chobanian & Avedisian School of Medicine started from a logical observation: in the general population, one of the determining characteristics of aging is the decline in the optimal functioning of the immune system.
Centenarians, a rare population of individuals who reach 100 or more, experience delays in age-related disease and mortality.
Based on this observation, the researchers wanted to know if their immune system remained functional until a very advanced age, having adapted to the diseases of existence.
An immune response that persists into old age
To identify immune patterns specific to aging and human longevity in these centenarians, the researchers performed single-cell sequencing on peripheral blood mononuclear cells (PBMCs) (a category of immune cells circulating in the blood) taken from seven centenarians, registered at the New England Centenarian Study.
They then integrated this dataset with two publicly available single-cell RNA sequencing (scRNA-seq) database sets of PBMCs to study and compare compositional and transcriptional changes in circulating immune profiles throughout human life and at a very advanced age.
Finally, they applied advanced computational techniques to analyze the combined data, to assess how cell type composition (the proportion of different cell types) and activity change with age, and whether centenarians manifest profiles escaping the expected age progression.
Their analysis confirms previous observations on aging but also identifies new cell-type-specific compositional and transcriptional changes in centenarians that indicate an optimal immune response even in old age.
“Our data support the hypothesis that centenarians have protective factors that allow them to recover from illness and reach old age,” says the study’s lead author, Tanya Karagiannis.
Decades of exposure to infections that make a difference?
So when people are exposed to and recover from infections, their immune system learns to adapt, but this ability tends to decline with age. “
“The immune profiles we observed in centenarians confirm a long history of exposure to infections and their ability to recover from them and support the hypothesis that centenarians benefit from protective factors that increase their ability to recover from infections. infection”said Paola Sebastiani, co-author
It remains to be seen how and why this “elite” has different protective factors that have evolved in their own way throughout life. Going further, the researchers believe these findings provide a basis for studying immune resilience mechanisms likely contributing to longevity.
“Centenarians, and their exceptional longevity, provide a ‘model’ for how we might lead more productive and healthier lives. We hope to continue to learn all we can about resilience against disease and extending one’s lifespan”said George J. Murphy also co-author.