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Posted on Sep 05, 2006, 7 a.m.
By Bill Freeman
Imbalances in the immune systems of people aged over 65 make them more prone to illnesses like flu or bacterial infections as a result of cuts and falls. Thousands of infections could be prevented each year in older people and hospital stays reduced following findings from two studies which show that imbalances in the immune systems of people aged over 65 make them more prone to illnesses like flu or bacterial infections as a result of cuts and falls.
Imbalances in the immune systems of people aged over 65 make them more prone to illnesses like flu or bacterial infections as a result of cuts and falls.
Thousands of infections could be prevented each year in older people and hospital stays reduced following findings from two studies which show that imbalances in the immune systems of people aged over 65 make them more prone to illnesses like flu or bacterial infections as a result of cuts and falls.
The separate studies carried out at the University of Birmingham and the Royal Free and University College Medical School were both funded by the Biotechnology and Biological Sciences Research Council (BBSRC) as part of its Science of Ageing and Experimental Ageing Research Initiatives.
Researchers at the University of Birmingham looked at the immune systems of older patients suffering from hip fractures. They found that the most abundant form of white blood cells, whose job it is to defend against invading microbes, are only half as effective in people aged over 65 as they are in younger people, suggesting that older people respond to stress differently.
When responding to physical stress like a hip fracture, people's bodies produce two hormones, cortisol which suppresses the immune defence system and DHEAS which stimulates it.
The researchers found that in patients over the age of 65, their levels of cortisol were higher than their levels of DHEAS, suggesting that their bodies were actually lowering their defence systems and making them prone to infections by impairing the function of their white blood cells.
"What is particularly exciting about this finding is that in laboratory experiments we can improve the efficiency of white blood cells by adding DHEAS," explains lead researcher Professor Janet Lord. "We are now going to explore whether treating patients with this hormone can help them fight infections."
In a separate study, researchers from the Royal Free and University College Medical School, looked specifically at skin infections in older people, studying the role of T lymphocytres, a type of white blood cell crucial in fighting infection.
By introducing minor infections to the skin of old and young volunteers, the researchers found that cells from older people had fewer receptors to direct the T lymphocytes to where they are needed, than younger people. This deficit resulted in less T lymphocytes reaching the infection site.
Professor Arne Akbar who led the study, says that older people are more susceptible to skin infections, skin cancers and poor wound healing which can result in lengthy hospital stays.
"Our research shows that in some circumstances, older people have a specific immune response deficit in their skin, not necessarily a generalised lack of immunity. This is a new and exciting concept, the challenge now is to understand what the deficiency is and how to reverse it."
