Supercentenarians possess exceptionally high levels of specialised cancer-fighting immune cells that could explain their remarkable longevity, according to a study by researchers at Osaka University in Japan.
The research team, led by Kousuke Hashimoto, detected unusually high concentrations of cytotoxic CD4 T lymphocytes in individuals aged 110 and older. The findings suggest that the human immune system may not inevitably deteriorate in extreme old age, but instead enter a state of adaptation to counter heightened health risks such as cancer.
Hashimoto and his team had previously identified the specific cell, known as a CD4 CTL lymphocyte, as a distinctive biological marker among people who live past 110. Cytotoxic T lymphocytes are white blood cells that form a key component of the adaptive immune system, responsible for scanning the body to target and destroy abnormal cells or pathogens.
In their latest study, the scientists aimed to quantify how the presence of these protective cells changes across different stages of aging. They examined blood samples from three distinct age groups: eight people between 70 and 99 years old, ten people between 100 and 109, and ten supercentenarians aged 110 or older.
Blood tests show immune cell spike
Addressing the size of the study, Hashimoto explained that Japan has only around 150 living supercentenarians, making a cohort of ten participants highly significant for longevity research.
The blood tests revealed a sharp increase in CD4 CTL levels corresponding with advanced age. The specialized cells accounted for roughly 4 percent of total T lymphocytes in participants aged 70 to 99, nearly 10 percent in centenarians aged 100 to 109, and more than 17 percent in supercentenarians. This means supercentenarians hold double or triple the proportion of these defense cells compared to younger elderly cohorts.
Crucially, the analysis showed that these lymphocytes displayed no signs of cellular exhaustion. Despite the advanced age of the host, the cells maintained their full capacity to destroy cancerous cells and virus-infected targets.
Implications for anti-cancer treatments
Researchers believe these lymphocytes expand in response to immune challenges that accumulate over decades, including cellular anomalies and reactivated latent viruses. The team noted that understanding why these cells proliferate in certain exceptionally long-lived individuals, and pinpointing their exact targets, could help scientists replicate the beneficial immune response in the broader population.
The Japanese findings align with research conducted in Europe on exceptionally long-lived individuals. In September of last year, researcher Manel Esteller of the Sant Pau Research Institute in Barcelona published a detailed investigation into María Branyas Morera, who was recognized as the world's oldest living person until her death in 2024 at the age of 117 years and 168 days.
Barcelona study on world's oldest woman
Esteller observed that supercentenarians are enriched with specialized immune cells equipped to attack biological threats, including potential cancer cells. He pointed out that Branyas had overcome numerous infections throughout her long life.
Notably, Branyas became the oldest known person in Spain to contract COVID-19, surviving the virus while remaining completely asymptomatic. Esteller highlighted her case as evidence of the powerful immune defenses present in supercentenarians.
