Somewhere in Olmsted County, Minnesota, there are people who blew past their 100th birthday without ever developing heart disease, cancer, or dementia. They are not just lucky. According to converging research from the Mayo Clinic Study of Aging and several independent longevity cohorts, these individuals share a distinct set of genes that remain active in their immune cells long after those same genes have gone quiet in most people. The pattern, built from decades of blood sample analysis and cutting-edge single-cell profiling, is reshaping how scientists think about extreme healthy aging: not as the mere absence of disease, but as an active biological program that can be measured, studied, and potentially replicated.
What decades of blood samples revealed
The Mayo Clinic Study of Aging (MCSA) has tracked thousands of adults in Olmsted County since 2004, assembling one of the most detailed longitudinal datasets on how cognition, biomarkers, and disease trajectories shift with age. A peer-reviewed paper from this cohort, published in 2025, examined breakpoints in Alzheimer’s biomarkers across the aging spectrum, confirming the study’s ability to distinguish healthy agers from those sliding toward disease. Paired with stored plasma from the Mayo Clinic Biobank, that infrastructure has let researchers measure molecular markers of cellular senescence in both living tissue and circulating blood.
One of the sharpest molecular findings involves a protein called IL-23R. In a 2024 study published in Nature Aging, Mayo-linked researchers identified IL-23R as a senescence-associated biomarker that rises steadily in typical adults as damaged, “zombie” senescent cells accumulate and drive chronic inflammation. “We were surprised by how consistently IL-23R tracked with senescent cell burden across tissue types,” the study’s senior author, Nathan LeBrasseur, told Mayo Clinic’s research communications team. In people who age without major disease, that inflammatory escalation appears blunted. The gene expression patterns behind it look fundamentally different from what researchers observe in average older adults, and the differences are not scattered randomly. They cluster in immune pathways that govern how aggressively the body responds to stress, infection, and tissue damage.
Separate from the Mayo cohort, single-cell profiling of blood cells across the human lifespan has added another dimension. In a study whose findings were highlighted by the U.S. National Institutes of Health, investigators led by Kosuke Hashimoto and colleagues used multi-modal single-cell profiling, published in 2023, to map which genes stay switched on or off in the immune cells of extremely long-lived individuals compared with younger adults. The result was striking: centenarians maintained immune cell compositions and gene activity patterns that more closely resembled those of people decades younger. They retained robust populations of certain T cells and natural killer cells that typically wither with advancing years. The NIH summary emphasized that centenarians often show a more diverse and flexible immune repertoire, suggesting their bodies keep a youthful-like capacity to respond to new threats.
A pilot transcriptomics study published in Frontiers in Genetics reinforced these findings from a different angle. Researchers compared healthy centenarians aged 100 to 104 against mid-life controls and asked a pointed question: do disease-associated risk alleles behave differently in people who carry them but never get sick? The answer was yes. Centenarians harbored many of the same genetic risk variants as everyone else, but the expression levels of those variants differed in ways that appear protective. The same genetic cards, played differently.
The concept of aging without major disease has also been formalized outside Mayo. The Super-Seniors Study, published in BMC Geriatrics in 2013, recruited exceptionally healthy older adults with no major diseases at enrollment and tracked their health over a decade. Now more than 12 years old, that study found the absence of disease was not random but correlated with identifiable genetic factors, reinforcing the idea that healthy extreme aging has a measurable biological basis. These individuals are not merely survivors. They appear to possess active protective mechanisms encoded in their genomes and immune systems.
The big questions that remain open
No single published paper from the MCSA has yet released a definitive list of the specific genes that remain active in centenarians. The converging evidence from multiple cohorts points toward immune-related gene sets, including genes governing T-cell maintenance, natural killer cell function, and inflammatory signaling pathways such as the IL-23/IL-17 axis, but the exact catalog, the regulatory networks connecting them, and the thresholds that separate a longevity signature from normal aging have not been consolidated into one public dataset. Different studies emphasize slightly different pathways, and the field has not agreed on a standardized panel that clinicians could order as a test. The headline claim of “specific genes” reflects the direction of the research rather than a finished inventory.
Whether these gene expression differences cause healthy aging or result from it is also unresolved. A study from the New England Centenarian Study, published in PLOS ONE, found that long-lived individuals carry specific genetic signatures rather than simply lacking risk alleles. That distinction matters: it suggests longevity is an active genetic program, not just the absence of harmful variants. But proving causation requires interventional studies that have not been completed in humans. No one has yet altered key longevity-linked genes or pathways in mid-life and shown that doing so reliably extends healthy lifespan.
The longitudinal IL-23R data from Mayo-linked biobank samples demonstrates that senescence biomarkers can be measured in stored plasma, but repeated measurements of the same individuals across the full span of the study have not been published. Most molecular aging work relies on cross-sectional comparisons between age groups rather than tracking one person from middle age into extreme old age. That gap limits how confidently researchers can claim a gene expression pattern observed in a centenarian was present decades earlier, rather than emerging late in life as a downstream effect.
Direct testimony from centenarian participants confirming lifelong absence of major disease is limited in the published literature. Cohort studies like the Super-Seniors Study use strict inclusion criteria at recruitment, but full medical histories before enrollment depend on records that may be incomplete. “Without major disease” should be understood as “without documented major disease by study criteria” rather than an absolute guarantee.
There is also the question of environment and lifestyle. Many centenarians report moderate physical activity, strong social ties, and low exposure to smoking, but quantifying those factors over a century of life is extraordinarily difficult. Protective gene variants might only confer benefits in certain dietary or social contexts, and harmful variants might be neutralized by favorable environments. Current datasets are not yet rich enough to untangle these layers with high confidence.
Why immune aging research is converging on centenarians
The practical stakes are significant. Mayo Clinic researchers are already testing senolytic drugs, compounds designed to clear senescent cells from the body, in early-phase human trials. If the gene expression patterns identified in healthy centenarians can be mapped precisely, they could serve as targets for therapies that mimic the centenarian immune profile in ordinary people. The goal would not be to make everyone live to 100 but to compress the period of disease and disability that typically precedes death.
For now, no consumer genetic test can tell you whether your immune system is aging like a centenarian’s. The research is still in the phase of identifying and validating biomarkers, not deploying them clinically. But the trajectory is clear: what once looked like an inscrutable gift of fortune is turning out to be a set of molecular switches that science can read and, eventually, may learn to flip.
The biology of healthy centenarians is best understood not as a solved puzzle but as a map whose key landmarks have been sketched. The finer details, the specific gene lists, the causal proof, the life-course data, are still being filled in. What the Mayo Clinic study and its companion research have established, as of mid-2026, is that the map is real and worth following.
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*This article was researched with the help of AI, with human editors creating the final content.
