The Aging Immune System

The immune system changes that seem to accompany old age can have a direct impact on a person's longevity. Not only does your immune system protect you against viruses and bacteria, but it also helps identify and remove cancer cells and toxins. As you get older, the potential for these elements to cause damage in your body increases.

This is confirmed. What triggers these changes in immune system function (and how they develop and progress) is not. Research suggests that old-age-related immune system dysfunction, sometimes known as "inflamm-aging," may, at least in part, cause and/or explain some of the known aspects of the aging processes. In fact, chronic inflammation is believed to contribute to a whole host of chronic and terminal diseases from cancer to Alzheimer's disease.

Cellular Changes

The immune system is made up of cells, substances, and organs. The thymus, spleen, tonsils, bone marrow, and lymphatic system produce, store, and transport cells and substances, such as antibodies, interleukins, and interferon.

As you age, critical cells in the immune system decrease in number and become less functional. Those that are of special interest to gerontologists (scientists who study aging) are the class of white blood cells called lymphocytes, which fight invading bacteria and other foreign cells.

Lymphocytes fall into two major classes:

• B-cells mature in the bone marrow. One of their functions is to secrete antibodies in response to infectious agents or antigens.
• T-cells develop in the thymus, which shrinks after puberty. There are two subtypes: Cytotoxic T-cells attack infected or damaged cells directly. Helper T-cells produce powerful chemicals, called lymphokines, which mobilize other immune system substances and cells.

While the number of T-cells remains fairly constant as you age, the portion of them that proliferate and function declines. Furthermore, T-cells destroyed by cancer treatments such as chemotherapy and radiation take longer to renew in older people than they do in younger people.

Beyond making you more prone to common viruses and bacterial infections, such immune system changes can have a much greater impact.

Interleukins—of which there are more than 20—serve as messengers, relaying signals that regulate the immune response. Some, like interleukin-6, rise with age, and it is speculated that they interfere with the immune response in some way. Others, like interleukin-2, which stimulates T-cell proliferation, tend to decrease with age.

When it comes to the immunological theory of aging, some research points to increasing immunogenetic diversification of human cells as the culprit, as opposed to the shifting numbers of cells.

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

Scientists continue to discover the complexities of the aging body and the many interdependent and interconnecting genetic, biochemical, and physiological processes involved. As this understanding grows, their findings could lead to better health, less disability, and greater independence in later life, and potentially longer lifespans. 

Learn More: Click Here