According to a new  study  published in  Lancet eBiomedicine, centenarians, or people who live to be 100 years or older, may have a unique "blueprint" in their immune cells that contributes to their "exceptional longevity."

Study details and key findings

For the study, researchers analyzed immune cells circulating in the blood from seven North American centenarians. The mean age of these participants was 106 years. They then compared this information to data from publicly available single cell RNA-sequencing datasets, which included seven additional centenarians and 52 younger individuals (ages 20-89).

Overall, the researchers found that the centenarian participants had immune profiles that did not follow patterns typically associated with natural aging.

For example, the researchers found that centenarians have substantial changes in the composition of their immune cells with age, including novel changes in the M14, M16, mDC, and pDC myeloid cell types. The researchers also discovered changes in the composition of T and B cells in centenarians.

When examining age-related changes in gene expressions, the researchers uncovered that centenarians had a unique protein signature that was not seen in younger participants. Some genes, such as those that are linked to mitochondrial and metabolic regulation, were also expressed differently in centenarians, which could play a role in their longevity compared to others.

"Based on gene expression changes, we identified cell type-specific transcriptional signatures of extreme longevity that include aging-related changes as well as unique gene changes in the immune profiles of centenarians," the researchers wrote.

Commentary

According to Paola Sebastiani, director of the  Center for Quantitative Methods and Data Science, as well as the  Institute for Clinical Research and Health Policy Studies, at  Tufts Medical Center and a senior author on the study, the study's findings "provide support to the hypothesis that centenarians are enriched with protective factors that increase their ability to recover from infections."

In general, the immune system weakens with age, making it more difficult for older people to fight off infections. However, centenarians may have a more robust immune system or unique immunological traits that help them stay healthy and live longer.

Stefano Monti, an associate professor of medicine, biostatistics, and bioinformatics at  Boston University's school of medicine and one of the study's senior authors, said it's currently unclear whether centenarians' unique immunological traits are genetic, naturally occurring, or due to a several outside factors.

"The answer to what makes you live longer is a very complex one," Monti said. "There's multiple factors, there's the genetics – what you inherit from a parent, there's lifestyle, there's luck."

Going forward, the researchers said they hope the study's findings can be used with existing research to help develop therapeutics for the world's aging population.

"Centenarians, and their exceptional longevity, provide a 'blueprint' for how we might live more productive, healthful lives," said senior author George Murphy, associate professor of medicine at Boston University's school of medicine. (Rodriguez, USA Today, 4/3; Karagiannis et al., Lancet eBiomedicine, 3/31)