Researchers at Washington University School of Medicine (WashU Medicine), in collaboration with Nationwide Children’s Hospital and King’s College London, have identified an immune cell ratio that may help predict healthy aging and future disease risk. Published in Immunity on October 9, the study analyzed approximately 12.4 million immune cells from 2,609 adults aged 20 to over 90 across multiple international cohorts.

The researchers focused on two types of white blood cells: granzyme B-producing and granzyme K-producing CD8 T cells. While granzyme B-producing cells help destroy diseased cells, granzyme K-producing cells may support immune signaling and coordinate responses. The findings suggest that a higher proportion of granzyme K-producing cells is associated with healthier aging, whereas granzyme B dominance may indicate immune dysfunction and an increased risk of chronic diseases.

To investigate long-term health outcomes, the team also analyzed data from approximately 50,000 UK Biobank participants, whose health records were tracked for up to 15 years. Individuals with a greater proportion of granzyme B-associated immune activity showed a higher risk of death and were more likely to develop conditions such as type 2 diabetes, hypertension, liver disease, and kidney failure.

The study highlights how immune systems can age along different biological trajectories, even among people of the same chronological age. These differences may help explain why some individuals remain healthy into older age while others develop age-related conditions earlier.

The researchers are now working toward developing a simpler, more affordable blood test to assess immune aging. Such a tool could support healthy aging, preventive healthcare, longevity research, and early disease-risk detection, potentially allowing clinicians to identify signs of immune dysfunction before symptoms emerge. Further validation is needed before this approach can be used routinely in clinical practice.

Source: https://medicine.washu.edu/news/immune-cell-map-uncovers-how-individual-aging-trajectories-diverge/