Year: 2012
Type: article
Abstract: The term immunosenescence is used to describe the decreased function of the immune system with age, and also to describe the phenotypic alterations in immune cells and cytokines that develop with age.The most dramatic phenotypic change is seen in the T cell compartment, where the percentage of cells with an effector memory phenotype increases, and the number and diversity of naïve cells decrease.In particular, large, often oligoclonal accumulations of CD28-CD8+ T cells develop.This hallmark change is largely attributable to CMV infection; the accumulating cells are the enormous "inflationary" virus-specific T cell population that are responding to this lifelong, smouldering, subclinical infection.In many populations, at least 80% of the elderly carry CMV, so CMV-driven changes in old age were easily ascribed to aging per se.There is broad agreement that CMV drives this characteristic phenotype of the aged immune system.There is also considerable evidence that the size of the CD8+CD28-population can be used to describe an "immune risk phenotype" which correlates with an increased inflammatory milieu ("inflammaging"), which may be a predictor of all cause mortality.However, the evidence that CMV contributes causally to the functional failings of the immune system in old age, rather than innocently providing a convenient biomarker, is much less convincing.This important question needs to be addressed with studies including enough CMV seronegative individuals to provide statistically valid data.
Source: Open Longevity Science
Author: Angela M. Tatum
Institution: Oregon Health & Science University
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W1988344580