Osaka University researchers identify immune cell link to extreme longevity

Researchers at Osaka University have identified a potential biological mechanism behind extreme longevity in supercentenarians, individuals aged 110 and older. According to a study published in the journal Cell Reports, these individuals exhibit a significant increase in a rare type of immune cell known as CD4 cytotoxic T lymphocytes (CD4-CTL).

Unlike traditional T cells, which are divided into helper cells that coordinate responses and killer cells that destroy targets, CD4-CTLs are rare hybrid cells. They possess the ability to both coordinate immune responses and directly attack infected or cancerous cells. The study, which analyzed blood samples from 28 Japanese participants across different age groups, found that these hybrid cells make up approximately 4% of T cells in those under 100, increasing to 9.6% in centenarians and reaching 17.6% in supercentenarians.

Lead researcher Kosuke Hashimoto noted that this represents an immune system “remodeling” in extreme old age. Rather than showing signs of exhaustion, the immune systems of supercentenarians appear to adapt by expanding this specific cell population to defend against tumors and other age-related diseases.