Understanding immune system variation between and within individuals may offer insight into healthy aging and disease. Here, Smithmyer et al. report longitudinal data collected from 100 healthy individuals over 2 years to identify immunological parameters that were constant within an individual but could distinguish between individuals. Using these parameters, the authors identified four immunotypes that reliably separated participants over time. They found that immunotypes based on peripheral blood samples translated into different immune cell behavior in vitro, suggesting that the immunotypes have functional consequences. These data offer insights into the healthy immune system and offer a resource to better understand perturbations caused by disease.
