People who live past 110 — supercentenarians — appear to share a distinctive immune feature: an abundance of a rare, dual-purpose T cell that may help keep them healthy.
Researchers at Osaka University, led by Kosuke Hashimoto, studied immune cells from 28 adults across three age bands (70–99, 100–109, and 110+). They found that CD4 cytotoxic T lymphocytes (CD4 CTLs) — hybrid cells combining features of helper and killer T cells — rose sharply with age: from about 4% of T cells in the younger group to 9.6% in centenarians and 17.6% in supercentenarians, nearly one-fifth of all circulating T cells. The findings were published in Cell Reports.
A possible role
The researchers theorize these cells may provide early immune responses against cancer — catching threats before tumors become clinically detectable — potentially contributing to longevity. “The selective expansion of certain T cells suggests that, even in extreme old age, the immune system may continue to adapt to age-related challenges,” Hashimoto said.
Why it matters — and the caveats
Immune aging is usually a story of decline, so signs of continued adaptation are intriguing. But this is a small study and the cells’ protective role is a hypothesis, not proof; it shows an association between these T cells and extreme longevity, not that boosting them would extend life. Still, it points to immune pathways worth exploring in aging research.