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What is immune resilience? -

Immune resilience is defined as a person's ability to maintain a robust, youthful immune system.

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Restoring immune balance -

To elaborate, immune resilience is the capacity to control inflammation and rapidly restore immune balance following a disease challenge.

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The benefits of robust immune resilience -

Individuals with optimum levels of immune resilience are most likely to live longer. They are also more likely to resist diseases and infections, and have a better chance of surviving diseases when they develop.

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The survival-associated pattern -

This survival-associated pattern is related to the immune system's ability to function swiftly and restore activities that encourage disease resistance.

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What are the signs of a strong immune system? -

Besides allowing the body to recover quickly from illnesses and infections, there are several other indicators that reveal a strong immune system.

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High energy levels -

When the immune system functions well, people have more energy and feel less tired. This is because a strong immune system helps combat viruses and bacteria that can promote fatigue.

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Infrequent illnesses and infections -

Another indicator of a robust immune system is infrequent illnesses, things like colds, influenza, and other infections. This is due to the body's ability to fight off pathogens quickly and efficiently.

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Fewer or no allergies -

Allergies and immune system function are inherently linked. Allergic reactions cause inflammation throughout your body. People with fewer or no allergies generally possess a stronger, more effective immune system.

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Why do some people live longer? -

Researchers have found that certain gene signatures make people more likely to bounce back from disease and live longer.

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Measuring immune resilience -

Immune resilience plays a critical role in promoting long-term health and extending life. But how is immune resilience measured? In other words, why do humans manifest vast differences in lifespan, health, and susceptibility to infectious diseases?

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Preserving and restoring immune resilience -

Some persons preserve and/or restore optimal immune resilience regardless of age. Identifying why this is so is key to understanding why some people remain healthier throughout life than others.

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CD8+ and CD4+ T-cells -

Scientists can measure immune resilience in two ways. The first is based on the relative quantities of two types of immune cells, CD4+ T cells and CD8+ T cells, both of which are types of white blood cells.

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CD4+ T-cells -

CD4+ T cells coordinate the immune system's response to pathogens. They are often used to measure immune health. Higher levels of CD4+ T cells typically suggest a stronger immune system.

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CD8+ T cells -

Conversely, a low level of CD8+ T cells is also an important indicator of immune health.  CD8+ T cells are responsible for killing damaged or infected cells.

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An immune-boosting combo -

A combination of high levels of CD4+ T cells and low levels of CD8+ T cells reinforces immune resilience, a fact identified by scientists during the pandemic when patients with SARS-CoV-2 infection who carried this immune-boosting combo were least likely to develop severe COVID-19 symptoms. These findings were published in 2021 in the Journal of Allergy and Clinical Immunology.

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Gene expression signatures -

In the same study, researchers identified a second measure of immune resilience. This involves two gene expression signatures correlated with an infected person's risk of death. Gene expression is the process by which the information encoded in a gene is turned into a function.

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The difference between life and death -

One of the signatures, which included genes related to inflammation, was linked to a higher risk of death. The other, which included genes related to keeping inflammation in check, was linked to a greater chance of survival.

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The optimal combination -

Researchers found that participants who expressed the optimal combination of genes lived longer.

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Further study involving the TCF7 gene -

In April 2025, results of a further study posted by Neuroscience News found that immune resilience, particularly involving the TCF7 gene, protects against chronic inflammation, immunosenescence (the gradual deterioration of the immune system, brought on by natural age advancement), and cell death.

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Longevity marker -

The TCF7 (transcription factor 7) gene serves as a longevity marker and helps preserve immune cell regeneration and function.

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Mitigating the biological aging process -

Chronic inflammation, immunosenescence, and cell death are three major factors of aging and mortality. Immune resilience mitigates these biological aging processes and more, and confers survival advantages.

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Protective power -

A key takeaway from the study indicated that individuals in midlife with high immune resilience had a 69% lower mortality rate and a biological age advantage of up to 15.5 years. In other words, poor immune resilience at 40 equals the mortality risk of someone aged in their mid-fifties. A person of the same age with optimal immune resilience can therefore be expected to live nearly 16 years longer than a poorly resilient person.

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Resilience at any age -

Maintaining optimal immune resilience preserves youthful immune profiles at any age. Doing so enhances vaccine responses and significantly reduces the burden of cardiovascular disease, Alzheimer’s disease, and severe infections.

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Declining immune efficiency -

Over time, however, immune resilience decreases as our immune systems are subjected to multiple respond-and-recover cycles.

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What happens after age 70? -

In fact, after age 70, mortality rates converge between resilient and non-resilient groups, suggesting biological limits on lifespan extension.

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How to enhance immunity -

The study's findings underscore the importance of early midlife interventions to boost immune resilience to maximize health span. But how can you enhance immunity?

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Keep up to date with vaccines -

Vaccines, for example the flu shot, build immunity against specific diseases. These should be administered at an early age.

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Adopt healthy eating habits -

Adopting healthy and well-balanced eating habits in childhood and maintaining them throughout adulthood can also strengthen and improve the immune system.

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Quit smoking -

The harmful effects of smoking cannot be underestimated. If you smoke, quit! The benefits of turning your back on tobacco are immeasurable, not least the boost given to the immune system. Likewise, avoid excessive alcohol use.

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Keep active -

Being physically active and maintaining a healthy weight is known to keep your immune system in good shape. Exercise also relieves stress.

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Get enough sleep -

And it goes without saying that getting enough sleep is vital in order to strengthen and maintain immune resilience.

Sources: (Big Think) (Nature) (Advanced Science News) (National Institute on Aging) (ScienceDirect) (Journal of Allergy and Clinical Immunology) (Neuroscience News)

See also: What is microsleep, and why does it happen?

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