Study finds unusually high levels of killer T cells in people over 110
Researchers discovered that individuals aged 110 and older possess markedly elevated numbers of rare CD4 cytotoxic T lymphocytes, which may reflect ongoing immune adaptation.
Blood from 28 participants aged 70 to beyond 110 was examined, showing that CD4 cytotoxic T lymphocytes increase from about 4% in the youngest group to 17.6% among supercentenarians. The cells frequently undergo clonal expansion, with some individuals harboring a single clone that makes up more than half of the CD4 CTL population. Sequence comparisons linked many dominant clones to cancer-associated receptors, although the study subjects had no cancer diagnoses.
Lead author Kosuke Hashimoto notes that such immune remodeling may help counter the rise of senescent and malignant cells that accompany aging. The work, published in Cell Reports, was supported by multiple Japanese research foundations and institutions. Future research will aim to track how these killer T cells behave within body tissues and whether they contribute directly to exceptional longevity.
Why it matters
Understanding immune changes in the oldest people could inform strategies to promote healthy aging and cancer prevention.
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