Unusual immune cells may help supercentenarians stay healthy
People who live to 110 years or more, known as supercentenarians, are of particular interest to scientists seeking to understand the mechanisms behind exceptional longevity. A new study has identified an unusual type of immune cell that becomes more abundant in supercentenarians and may help protect them against cancer and other age-related threats, according to EFE.
The study, published in Cell Reports by researchers at Osaka University in Japan, examined blood samples from 28 Japanese adults divided into three age groups: 70–99, 100–109 and 110 years or older, CE Report quotes AGERPRES.
The participants included 20 women and eight men. All 10 supercentenarians in the study were women, reflecting the extreme rarity of men reaching this age, researcher Kosuke Hashimoto told EFE.
The researchers focused on T cells, an important component of the immune system. While T cells are generally divided into helper cells, which coordinate immune responses, and killer cells, which destroy infected or cancerous cells, supercentenarians were found to have unusually high levels of a hybrid type known as cytotoxic CD4 T cells.
These cells are rare during most of a person's life but appear to expand dramatically around the age of 100. Their average proportion increased from 4 percent among people aged 70–99 to 9.6 percent among those aged 100–109 and 17.6 percent among supercentenarians.
“We analyzed a rare cell population that is abundant in supercentenarians and found signs of immune remodeling at extremely advanced ages,” Hashimoto said. According to the researcher, the cells remain highly active rather than showing signs of immune exhaustion.
Many of the cells had undergone clonal expansion, meaning that individual cells multiplied to produce large populations of genetically similar cells. This suggests that they may have repeatedly encountered the same targets over the course of a person's life.
The researchers also made a surprising discovery: the molecular receptors found on these cells were largely similar to those identified in immune cells associated with cancer patients, even though the supercentenarians in the study had no history of cancer.
This raises the possibility that the cells could help the immune system recognize tumors before they become clinically detectable. However, the researchers stressed that this remains a hypothesis requiring further investigation.
The study could not establish whether there are significant differences between men and women because of the small sample size. Hashimoto noted, however, that a 2019 study involving male supercentenarians also observed an increase in cytotoxic CD4 T cells.
Researchers now want to determine where these unusual immune cells are located in the body and exactly what they recognize.
The scientists emphasized that the findings do not prove that cytotoxic CD4 T cells directly cause exceptional longevity. Nevertheless, the study provides new insight into how the immune system adapts in people who reach extraordinarily advanced ages and could contribute to a better understanding of healthy ageing and protection against age-related diseases.
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