Researchers at Yale School of Medicine have found that exaggerated responses of the immune system explain why the elderly succumb to viral infections more readily than younger people. Published in the November 19 Cell Host & Microbe, the study bucks the general belief that declining immune responses are to blame for susceptibility to viral infections.
Illness and death caused by viral infections tend to increase with age, indicating that aging impairs immunity, but the underlying mechanisms are unclear. To understand how aging modifies inflammatory response to viral infection, a research team led by Daniel R. Goldstein, M.D., associate professor of internal medicine and cardiology at Yale School of Medicine, infected young (2-4 months), middle-aged (8-10 months), and aged (18-20 months) mice with the herpes virus. This led to a rapid increase in inflammatory mediators, or cytokines, called interleuken 17. When the team examined the blood for inflammatory substances and examined the liver, they saw evidence of damage in only the aged cohort.