Mature & Aged Immune Systems and Common Ways to Boost Them

FROM THE LECTURE SERIES: AN INTRODUCTION TO INFECTIOUS DISEASES

By Barry C. Fox, M.D., University of Wisconsin

The immune system coordinates the complicated innate and adaptive immunity via cytokines. These are chemical messengers secreted by various immune system cells, acting on other cells, and coordinating perfect immune responses. But what effect does ageing have on the immune system?

Concept of vegetables that are useful for boosting immunity.
A healthy diet is one of the recommended methods to boost the immune system. (Image: Ekaterina Markelova/Shutterstock)

The Immature Immune System of Newborns

Much of a newborn’s immune system is dependent upon the transfer of immunity from the mother to the newborn before or during birth. For example, immunoglobulin protection is exclusive of the IgG type that is small enough to cross the placenta. The fetal immune system is derived from primitive stem cells, arising from inside the developing baby’s bone structure.

An illustration of a newborn baby reaching for a toy that looks like a virus.
The immune system of newborns is immature, making them more vulnerable to various infections. (Image: Nina Aleksandryuk/Shutterstock)

These stem cells later differentiate into specialized cells as the immune system matures. It takes the newborn’s immune system a minimum of four to six weeks to develop individual responsiveness.

The initial vaccination series of some infants aren’t usually complete until after one year. The reality is children before the age of one are much more vulnerable to infections.

This is a transcript from the video series An Introduction to Infectious Diseases. Watch it now, on Wondrium.

Concerns over the Hygiene Hypothesis

There are concerns known as the hygiene hypothesis—a potential disservice to the developing immune system by creating too clean of an environment. The developing immune system may need to be properly exposed to germs to function optimally. If the baby’s environment is too clean, for example, the production of T-helper cells may not be adequately stimulated. 

In a study conducted at Johns Hopkins, scientists also found that the timing of exposure to germs was crucial and that exposure during the first year of life was the most important. Their findings were based on an allergy and asthma study in inner-city environments where children were exposed to rodent and pet dander, household germs, and insect allergens. 

If exposed during their first year, the children were less likely to have allergy and asthma problems three years later. There also appears to be a slight benefit from growing up in a large family—with more germs—as well as growing up on a farm.

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Aging and Its Effect on the Immune System

While some people age healthily, the elderly are far more likely to contract infectious diseases. Respiratory infections, influenza, and particularly pneumonia are the leading causes of death in those over the age of 65. No one knows for sure why this happens, but most scientists agree that the increased risk correlates with a decrease in T-cells, possibly from the thymus shrinking with age and generating limited T-cells to fight off disease.

The aging body also responds more slowly to challenges by infectious agents. Changes in the overall immune system as the person ages are known as immunosenescence. Research has revealed that with age, the innate defenses lose some of their ability and the cells don’t communicate with each other like they used to. When this happens, it makes it difficult for cells to react quickly and appropriately to invading germs. 

As a consequence of reduced lymphocyte production, vaccination is not likely to generate a strong immune response—both B-cell and immunoglobulin. The response may even be below the threshold for protection. But despite the reduction in efficacy, vaccinations for influenza and pneumococcal pneumonia have significantly lowered the rates of sickness and death in older people when compared with non-vaccination.

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Benefits of Shingles Vaccination for the Elderly

An image of a man suffering from shingles with facial rashes/blisters
The elderly need to be aware of recognizing the signs of shingles within 72 hours of symptoms. (Image: VideoBCN/Shutterstock)

One exception to poor vaccine immune response is the shingles vaccine after 60. Since one in three individuals over the age of 60 will develop shingles, it’s important to get this vaccine. Shingles are a reactivation of chickenpox and rely on lymphocytes to remember prior viral exposure. 

In light of the immune reaction slowdown, the elderly need to be very careful and quite aware about recognizing the signs of shingles within 72 hours of symptoms. Why 72 hours? This is the window of opportunity for prescribing anti-viral shingles drugs. Medication may be effective in reducing both acute symptoms as well as incidence and severity of postherpetic neuralgia.

Learn more about respiratory and brain infections.

Signs and Symptoms of Shingles

Early twinging pains, itching, or unusual nerve sensitivity not attributable to injury. Burning of the skin (persistent in a limited area), followed by a red patch of skin without typical blisters. For eye or head shingles, a sensation that feels like something is irritating the eyes. 

In addition, one of the significant consequences of shingles, aside from the blisters and acute pain, is the dreaded postherpetic neuralgia, which occurs more frequently after 60. This is intermittent or continuous neural pain reactivated with infection. 

Antiviral medication cannot affect this type of pain if it’s not administered in the first 72 hours. Postherpetic neuralgia can last for many months and make normal daily activities very difficult. 

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Common Ways to Boost the Immune Systems of the Elderly

The most prevalent advice by doctors to boost the immune system is to eat a healthy diet full of vitamins and nutrients and to take exercise. Exercise is thought to benefit the immune system in several ways. It helps decrease stress, increases the circulation rate of antibodies and white blood cells, and surprisingly also brings about greater intestinal microbiome diversity. 

Moreover, people must avoid smoking, control their blood pressure, inject the annual flu shot, and get the shingles vaccine after 60 and the pneumonia vaccine after 65. Furthermore, one thing that has been added to the living healthy list is practicing meditation to reduce stress. Transcendental meditation has been recommended by the American Heart Association as a proven means to reduce blood pressure.

Common Questions about Mature and Aged Immune Systems and Common Ways to Boost Them

Q: What is the hygiene hypothesis?

The hygiene hypothesis happens when the environment is too clean for the immune system of newborns to develop. This hygienic environment can cause inadequate production of T-helper cells. The body may need to be exposed to germs in order for the immune system to function optimally.

Q: What happens to the immune system when people get older?

When people get older, the immune system becomes weaker and may not respond properly to infections. This happens because the thymus shrinks and consequently T-helper cell production decreases. Also, due to frailty, some cells lose their ability to communicate with one another.

Q: What are some common ways to boost the immune system?

The elderly have a weaker immune system compared to younger people. Hence, they need to boost their immunity through a healthy diet, exercise, doing meditation, reducing stress, and controlling blood pressure.

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