The Basics of the Immunological Theory of Aging

Theory Proponents Point to Changes in Immune Function as Cause of Aging

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The immunological theory of aging asserts that the process of human aging is, in fact, a mild and generalized form of prolonged auto-immune phenomenon. Simply put, the theory holds that the rate of aging, a highly complex series of processes, is largely controlled by the immune system. The process of aging is an incredibly complex phenomenon and it is not fully understood in the medical and science communities.

As we get more familiar with the process itself, we still have not uncovered the primary cause, which is where theories like the immunological theory of aging come in.

Basics of the Immunological Theory of Aging 

As humans age, we experience a whole host of changes to almost all of our physiological functions, including immunity and immune system function. Medical experts have proven that immune function does indeed decrease with age, which contributes to a whole host of well-known issues among seniors from increased health risks posed by common infections like a cold or the flu to greater occurrence of chronic inflammatory diseases. While the data suggests that changes in immune system function in the elderly could be a symptom of the aging process, proponents of the immunological theory of aging reverse the relationship. These theorists believe that our common symptoms of aging like chronic disease are caused by changes in the immune system.

The Aging Immune System

It is commonly known that the immune system changes that seem to accompany old age can have a direct impact on a person's longevity. The immune system is important in keeping our bodies healthy. Not only does it protect us against viruses and bacteria, it also helps to identify and remove cancer cells and toxins.

As we age, the potential for these elements to cause damage in our bodies increases.

But what is not known is what triggers these changes in immune system function and how they develop and progress. There is some strong human data that suggests that old age-related immune system dysfunction may, at least in part, cause and/or explain some aspects of the known aspects of the aging processes.

How Immune System Changes Might Affect the Body

Beyond being more prone to common viruses and bacterial infections, these immune system changes have much greater impacts. 

We know that as we age, the numbers of critical cells in the immune system decrease and become less functional. We also know that starting before age 20, the thymus (which is the area of the brain that is responsible for producing certain immune cells) begins to shrink. But when it comes to the immunological theory of aging, some in the medical science community point to increasing immunogenetic diversification of human cells as the culprit.

The theory holds that this increased diversification or cell mutation in old age may eventually led to a failure of cell recognition and the breakdown of certain physiological systems, which ultimately triggers autoimmune-like reactions like chronic inflammation.

Today, chronic inflammation is believed to contribute to a whole host of chronic and terminal diseases from cancer to Alzheimer's.

The Science of Aging

The immunological theory of aging is but one theory that attempts to explain why and how we age. While it is certainly a convincing one, it deals with extremely complex processes and systems (aging and immunity) that we don't fully understand. To learn more about why we age, be sure to check out our article, Why We Age: Theories and Effects of Aging.


Aging Under the Microscope; National Institutes of Health, National Institute of Aging.

Franceschi, C., and J. Campisi. "Chronic Inflammation (Inflammaging) and Its Potential Contribution to Age-Associated Diseases." The Journals of Gerontology Series A: Biological Sciences and Medical Sciences69.Suppl 1 (2014)

Fulop, T., JM Witkowski, G. Pawelec, C. Alan, and A. Larbi. "On the Immunological Theory of Aging." Interdisciplinary Topics in Gerontology39 (2014): 163-76. 

Walford, Roy L. "The Immunologic Theory of Aging." The Gerontologist 4.4 (1964): 195-97.

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