Aging Changes in Immunity

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Effect of changes

There is a slow, steady decrease in immunity after young adulthood. When the body is exposed to bacteria or other microorganisms (by an actual exposure or by immunization), fewer protective antibodies may be formed or they may be formed at a slower rate.

Flu shots or other immunizations may be less effective, and protection may not last as long as expected.

Later in life, the immune system also seems to become less tolerant of the body's own cells. Sometimes an autoimmune disorder develops -- normal tissue is mistaken for non-self tissue, and immune cells attack certain organs or tissues.

The immune system becomes less able to detect malignant cells, and cancer risk also increases with age as a result.

The immune system also becomes less able to detect foreign particles, and infection risk is greater.

Other things also increase the risk of infections. Sensation changes, gait changes , changes in the skin structure, and other "normal aging changes" increase the risk of injury in which bacteria can enter broken skin. Illness or surgery can further weaken the immune system, making the body more susceptible to subsequent infections. Diabetes, which is also more prevalent with age, can also lead to decreased immunity.

Besides slightly decreasing immunity, aging also affects inflammation and wound healing. Inflammation is an immune response -- when the immune system thinks there is trouble, it sends more cells to the site of the problem and this causes swelling, pain, redness, warmth and irritation, which are the hallmarks of inflammation. Inflammation often indicates infection, but may also occur due to autoimmune attack on "self" tissue as well.

Many older people heal more slowly. This may be directly related to changes in the immune system, or it may be a consequence of other problems such as diabetes or arteriosclerosis, which leads to decreased blood flow to some parts of the body such as the lower extremities.

Also, many older people take anti-inflammatory medications (to control conditions such as arthritis) and these are also known to slow wound healing.