Researchers built a human immune aging clock using single-cell multi-omics data from nearly 1.2 million peripheral blood mononuclear cells across 230 people. T cell gene expression was the strongest predictor of immune age, capturing known hallmarks like loss of naive T cells and contraction of T cell clones. The model highlighted the transcription factor RUNX1, whose expression falls with age in T cells. Deleting RUNX1 in young T cells triggered senescence, while restoring it in aged CD8+ T cells reduced senescent features in lab cultures and in living animal models. The work offers a quantitative way to measure immunosenescence and nominates RUNX1 as a candidate target for rejuvenating aged immunity. These findings are preclinical, and no human treatment has been tested.
