Plate Nº 94 · recorded October 10, 2026
Health & Medicine ResearchReported finding
Immune System Ages in Bursts Around 40 and 60, Study Finds
The immune system ages in sharp bursts around 40 and 60, not gradually, a study of 3.8 million immune cells finds — and the changes differ between men and women.
By Elena Vasquez4 min read861 words
In brief
- Researchers analyzed 3.8 million immune cells from nearly 2,000 healthy people aged 19 to 97.
- Immune aging accelerates around age 40 and again after 60, with major shifts in gene activity.
- T cells showed the most pronounced aging-related changes, and different T cell types drive each wave.
- More than 600,000 people in Singapore, about 11% of the population, live with autoimmune diseases.
- The study was published in Nature Communications in 2026 (DOI: 10.1038/s41467-026-76737-4).
The human immune system does not age gradually — it undergoes sharp bursts of accelerated aging around age 40 and again after 60, according to a large new study of 3.8 million individual immune cells published in Nature Communications.
Researchers at Duke-NUS Medical School in Singapore found that major shifts in gene activity cluster at these two ages, and that the changes unfold differently in men and women. The findings offer a potential explanation for a long-standing puzzle in age-related medicine: women live longer than men, yet they develop age- and immune-related conditions, including many autoimmune diseases, more often.
What did the researchers actually find?
The team, led by senior author Jacques Behmoaras, an associate professor at Duke-NUS's Center of Biomedical Data Science, analyzed the genetic activity of 3.8 million immune cells drawn from nearly 2,000 healthy people aged 19 to 97. The dataset included people of Asian ethnicity, among them Singaporeans. The researchers combined publicly available datasets into a single integrated "immune atlas" — one of the largest and most diverse resources of its kind.
At the two aging peaks, roughly at 40 and after 60, the fundamental machinery inside cells declines most. The genes hit hardest are those responsible for producing RNA and proteins — the molecules that carry out nearly every function a cell performs. When that production machinery falters, cells work less efficiently overall.
T cells, a type of white blood cell that coordinates the body's defense against germs, showed the most pronounced changes. People in their 40s displayed strong shifts in gene activity in one set of T cells; after 60, a second wave of changes appeared, driven by different T cell types. That difference suggests these cells play specialized roles at different stages of life.
The way these specialized T cells change their activity across the lifespan also differs between men and women.
Why does this matter for autoimmune disease?
The stakes are concrete in Singapore, where more than 600,000 people — about 11% of the population — live with autoimmune diseases such as lupus and rheumatoid arthritis. In these conditions, the immune system turns against the body and attacks major organs. Both age and sex strongly influence who develops them, and women bear the greater burden.
Behmoaras said the results challenge the common picture of aging as a slow, steady slide:
"We tend to think of aging as a gradual process, but our findings show that the immune system does not simply decline at a steady rate. Instead, we see distinct periods of rapid change, particularly around 40 and again after 60, with T cells playing a major role."
He added that understanding what drives these windows of immune aging could eventually help identify when, and for whom, interventions might do the most good — and could shed light on why some autoimmune conditions disproportionately affect women.
How could this lead to personalized treatments?
The study's central contribution is a detailed map of how the immune system changes across the lifespan — and, crucially, how those trajectories diverge by sex. Professor Sheemei Lok, Duke-NUS's interim vice dean for research, said this knowledge is fundamental to abandoning a one-size-fits-all approach to aging in favor of more precise strategies for maintaining health.
The researchers went a step further and used their data to build AI models that predict biological age — an estimate of the body's "true" age, which can differ from the number of years a person has lived. They hope to use this tool to study specific biological pathways and time windows in which interventions could be tailored to a patient's sex.
Study author Antonio Bertoletti, a professor in Duke-NUS's Emerging Infectious Diseases Signature Research Program, said the work builds on earlier evidence that T cells are among the immune cells most affected by aging. He also pointed to a practical implication:
"Changes in T cell function may help explain why older adults are more susceptible to infections and inflammatory conditions."
The next research step, he noted, is understanding what drives these nonlinear changes in T cells over time.
What are the study's limits?
The findings come from healthy participants, so they describe normal immune aging rather than disease progression. The cell data came from publicly available datasets that the researchers combined and integrated, rather than from a single cohort followed over time. Whether the aging bursts measured in blood circulating cells fully reflect immune aging elsewhere in the body, such as in organs and tissues, remains an open question.
Still, the scale of the atlas — millions of cells from nearly 2,000 people spanning eight decades of life — gives scientists an unusually rich foundation for future work on sex-specific approaches to healthy aging.
The research was conducted at Duke-NUS's Center of Biomedical Data Science in collaboration with the school's Signature Research Programs in Cardiovascular and Metabolic Disorders, Cancer and Stem Cell Biology, and Emerging Infectious Diseases, along with partners at NUS Yong Loo Lin School of Medicine. The paper, by Harry Park and colleagues, appears in Nature Communications (DOI: 10.1038/s41467-026-76737-4).
via Medical Xpress (Source)