Japanese researchers at Osaka University led by Kosuke Hashimoto have discovered that supercentenarians possess high levels of specialized immune cells that actively fight cancer.
Blood analyses revealed that individuals aged 110 and older carry more than four times the proportion of CD4 cytotoxic T-lymphocytes found in younger elderly adults, according to findings reported by New Scientist.
The specialized immune cells, known as CD4 CTLs, recognize and destroy health threats including cancer cells and reactivated viruses. Kosuke Hashimoto said he considered it remarkable that the human immune system retains the capacity to adapt to accumulating challenges even after more than a century of life.
Immune cell changes across age groups
To quantify how these protective cells change across different stages of aging, the research team examined blood samples from three distinct age brackets. The study evaluated eight individuals aged between 70 and 99 years, ten individuals aged between 100 and 109 years, and ten supercentenarians aged 110 years or older.
Hashimoto emphasized that ten supercentenarians represents a significant sample size, noting that Japan's national census lists only about 150 people nationwide who have reached the age of 110. In human biology, supercentenarians are individuals who have lived to 110 years or beyond, an achievement reached by an extremely small fraction of the global population.
The blood tests demonstrated a steady increase in the proportion of CD4 CTLs relative to total T-cells as participants aged. The cells accounted for 4 percent of total T-cells in the group aged 70 to 99, rising to almost 10 percent in centenarians aged 100 to 109, and exceeding 17 percent among supercentenarians aged 110 and older.
Critically, tests showed that these immune cells exhibited no signs of T-cell exhaustion, a state where immune cells lose their functional capacity to kill cancerous or virus-infected cells. Hashimoto said the results indicate that CD4 CTLs may contribute directly to maintaining immune control over cancer in extreme old age.
Potential for medical applications
As the human body ages, challenges to the immune system such as abnormal cell growth and dormant viral reactivations become far more frequent. Hashimoto explained that researchers believe CD4 CTLs multiply in direct response to these age-related threats. He noted that if scientists can determine why these cells proliferate in certain elderly individuals and identify their specific targets, medical science may eventually replicate the beneficial immune response in broader populations.
The findings align with independent research conducted in September last year by Manel Esteller of the Sant Pau Research Institute in Barcelona, Spain. Esteller performed a detailed study on Maria Branyas Morera, who was recognized as the world's oldest living person prior to her death in 2024 at the age of 117 years and 168 days.
Esteller stated that Hashimoto's research confirms that people who live past 100 possess an enriched set of immune cells capable of attacking immune threats and cancer cells. He noted that Morera had contracted numerous infections during her long life but successfully defended against all of them, including an asymptomatic case of COVID-19 when she was the oldest known infected person in Spain.
The report on supercentenarian immunity was published by Ukrainian news agency UNIAN alongside lifestyle health updates. Researchers hope that continuing studies into supercentenarian blood profiles will unlock new therapeutic targets for cancer prevention and immune preservation in aging populations worldwide.
