Why does immune system weaken with age

We live in a time of high average life expectancies. However, our long evolutionary history has adapted us for different lifestyles and even life expectancies , and these have changed drastically.

As a result, immunity not only weakens in older age; it also becomes imbalanced. Chronic, low-grade inflammation is associated with almost all conditions linked to older age, including type 2 diabetes, cardiovascular disease, cancer, and dementia.

It also plays a leading role in certain autoimmune conditions that are more common in older adults, such as rheumatoid arthritis. Meanwhile, the loss of adaptive immunity that comes with older age not only makes people more susceptible to infections; it can also reactivate dormant pathogens that were previously suppressed.

In addition, the weaker adaptive immunity of older adults means that their bodies respond less strongly to vaccinations, such as the annual flu shot. The authors of a study in the journal Frontiers in Immunology explain:.

When inflammation becomes prolonged and persists, it can become damaging and destructive. This does not appear to happen as effectively in older adults. Senescent cells have shorter telomeres, which are the protective caps at the tips of chromosomes.

Just as the plastic caps on the ends of shoelaces prevent them from fraying, telomeres prevent vital genetic material from becoming lost when the chromosome is copied during cell replication. Telomeres get a little shorter every time a cell divides, until, eventually, division has to stop completely. If the cell survives, it becomes steadily more dysfunctional. Senescent immune cells produce more immune signaling molecules called cytokines, which promote inflammation.

Scientists have linked high levels of IL-6 and TNF-alpha to disability and mortality in older adults. They have a particularly strong association with type 2 diabetes, cardiovascular disease, neurodegenerative disease, and cancer.

As the number of pro-inflammatory cells increases, there is an increase in the number of immune cells called M1 macrophages more pro-inflammatory and a decrease in the number of M2 macrophages more immunoregulatory.

These changes in the frequency of M1 and M2 cells seem to be associated with an increased risk of developing plaques comprising fat and debris, which block the arteries in atherosclerosis. Through adaptive immunity, the immune system learns to recognize and neutralize particular pathogens. A type of immune cell known as a T cell plays a crucial role in adaptive immunity.

They then differentiate into cells that are specialized to mount future immune responses against the same pathogen. As you grow older, your immune system does not work as well. The following immune system changes may occur:. McDevitt MA. Aging and the blood. Brocklehurst's Textbook of Geriatric Medicine and Gerontology. Philadelphia, PA: Elsevier; chap Clinical immunology: immune senescence and the acquired immunodeficiency of aging.

Walston JD. Common clinical sequelae of aging. Older people have smaller amounts of complement proteins Complement System One of the body's lines of defense immune system involves white blood cells leukocytes that travel through the bloodstream and into tissues, searching for and attacking microorganisms and Although the amount of antibody produced in response to an antigen remains about the same overall, the antibodies become less able to attach to the antigen. This change may partly explain why pneumonia Overview of Pneumonia Pneumonia is an infection of the small air sacs of the lungs alveoli and the tissues around them.

Pneumonia is one of the most common causes of death worldwide. Often, pneumonia is the final It causes a fever, runny nose, sore throat, cough, headache, muscle aches myalgias , and a general Infective endocarditis occurs when bacteria enter the bloodstream and travel The toxin makes muscles contract involuntarily and become rigid.

Tetanus usually develops after a wound or These changes may also partly explain why vaccines are less effective in older people and thus why it is important for older people to get booster shots which are available for some vaccines. These changes in immune function may contribute to the greater susceptibility of older people to some infections and cancers.

Avoid excessive alcohol consumption — that means five or more drinks on one occasion during five or more days in a day period. Drinking boosts your risk of infection. Heavy drinkers also make up more than one-third of those with tuberculosis.

While excessive drinking is detrimental, occasional consumption of red wine, in small amounts, is compatible with the anti-inflammatory Mediterranean diet plan. Avoid exposing your skin to too much sunlight. While vitamin D from sunlight does help support healthy immune function, too much UV radiation can alter your DNA, ultimately boosting your risk of cancer. You also may get more cold sores. Avoid burning coal and or cooking too much with charcoal. Also avoid man-made chemicals, including hydrocarbons, as much as possible.

A weakened immune system is one result.