University of California Irvine Study Sheds Light on Why Older Adults Are More Susceptible to Infectious Diseases

Some diseases are more severe in extremes of ages. Malaria, pneumonia, and diarrhea are more severe in under-fives while cardiovascular diseases, diabetes, and arthritis worsen with increasing age. This may be a result of an immature immune system in very young children, with wear out of the immune system and tissue deterioration in the aged. The efficacy of immunization has been noted to be on the decline with increasing age, further increasing infection risk in the older population.

Old Man Walking

Old Man Walking

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One of the recent pandemics, SARS-CoV2 was noted to affect the elderly in a more severe way than young adults.

This disease severity among older adults has been a cause of concern for many people, leading to research to find out the cause, and maybe profer a solution to it. The University of California, Irvine school of medicine has also carried out research in line with this.

The immune system’s quarterback

Lymphocytes help the body to fight infections with the B lymphocytes forming the humoral or antibody-mediated immune system. The T lymphocytes form the cell-mediated immune system which produces killer, helper, and suppressor cells.

The T lymphocyte is the quarterback of the immune system, overseeing the immune system in fighting off infection.

Research carried out by the UCI team showed that T cell immunity declines with aging which in turn causes an increase in infectious disease severity and mortality as one gets older. This can be attributed to the increased addition of carbohydrate chains which are complex and branched, to proteins. This addition causes the suppression of T cells’ function.

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With increasing age, the production of the sugar metabolite N-acetylglucosamine in T cells increases. Also, the T cell cytokine, interleukin 7, increases its signaling as we get older. These two, according to this research, have been shown to cause an increase in the branched carbohydrate chains (glycan) with age, thus, leading to T cell function suppression in the older populations. This occurs more in females than males.

According to this study, immune dysfunction associated with aging (immunosenescence) can be reduced by decreasing the branched glycans elevation. This process in old female mice reduced the severity of Salmonella infection.

Further research to improve the immune system in the elderly has led to the discovery of some already existing drugs that can reverse the decline of the immune system. In 2012, it was discovered that the immune response of some research participants to flu vaccination was improved by about 20%. Here, low-dose courses of everolimus, a variant of rapamycin were given for six weeks to elderly participants. The drug was well-tolerated and safe, with improved function of the immune system.

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Clinical significance

It is no longer news that the older one becomes, the more the decline in the major organ systems of the body. The immune system is not an exception. Hence, older adults are at increased risk of infectious diseases than young adults. The protective effect of vaccination is also reduced in older adults.

With improvements in technology, people tend to live longer. Therefore, it is necessary to study ways of improving the immune system in the elderly to enable them to lead healthier lives. In this study, the effect of reduction in the production of branched glycans in the elderly improved T cell function. Since T cell is the quarterback of the immune system, improving its function in the elderly will lead to reduced morbidity and mortality from infectious diseases in this age group.

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It is important to find out ways of improving the age-dependent progressive deterioration of the immune system. Enhancing the T cell function by decreasing branched glycans production in old age proves promising. The need for further clinical trials cannot be overemphasized.


Age-associated impairment of T cell immunity is linked to sex-dimorphic elevation of N-glycan branching



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