A new clock that analyzes the age of the immune system may be the next big thing in aging biomarkers.
Measuring the age of your immune system
As we age, our immune systems begin to decline due to many factors, including the thymus shrinking and producing ever-fewer T cells, the ever-increasing chronic inflammation called “inflammaging”, dysfunctional immune cells doing more harm than good, and a lifetime of microbial burden taking its toll. This gradual decline of the immune system is known as immunosenescence.
This is no surprise, considering the many functions that the immune system performs and all of the cell types that perform them. From repelling invading pathogens and facilitating wound healing to clearing away cellular garbage, the immune system is the workhorse of the body and essential to life.
In a new study, researchers have published the details of a new aging clock that measures how well the immune system is working. It could be a valuable tool for interventions that target the aging processes in order to prevent age-related diseases .
It is currently a challenge to accurately ascertain the state of an individual’s immune system, but these researchers claim that IMM-AGE can be used to analyze the immune system to give an accurate prediction of disease risk and life expectancy.
IMM-AGE is a biological clock that may help track the immune decline that occurs in old age, which is known as immunosenescence. The research team believes that it could provide an “immune age” and be used alongside chronological age to help inform healthcare and drug development.
Immune responses generally decline with age. However, the dynamics of this process at the individual level have not been characterized, hindering quantification of an individual’s immune age. Here, we use multiple ‘omics’ technologies to capture population- and individual-level changes in the human immune system of 135 healthy adult individuals of different ages sampled longitudinally over a nine-year period. We observed high inter-individual variability in the rates of change of cellular frequencies that was dictated by their baseline values, allowing identification of steady-state levels toward which a cell subset converged and the ordered convergence of multiple cell subsets toward an older adult homeostasis. These data form a high-dimensional trajectory of immune aging (IMM-AGE) that describes a person’s immune status better than chronological age. We show that the IMM-AGE score predicted all-cause mortality beyond well-established risk factors in the Framingham Heart Study, establishing its potential use in clinics for identification of patients at risk.
If this new clock proves reliable, it could take its place alongside the gold standard for aging biomarkers, the epigenetic clock, along with the newer ribosomal clock. It may prove useful in the development of drugs and vaccines as well as clinical trials in which the aging processes are the focus of therapies. There is certainly a need for more aging biomarkers, so this could potentially be added to the toolkit to help our industry develop therapies.
 Alpert, A., Pickman, Y., Leipold, M., Rosenberg-Hasson, Y., Ji, X., Gaujoux, R., … & Furman, D. (2019). A clinically meaningful metric of immune age derived from high-dimensional longitudinal monitoring. Nature Medicine, 1.