What is the effect of aging on the immune system?

What is the effect of aging on the immune system?

• A. Decreased risk for infections
• B. Increased risk for infections and autoimmune diseases; reduced function of neutrophils and macrophages; slower immune responses
• C. No effect
• D. Enhanced immune competence

Answer: (B)

Aging brings immunosenescence, a gradual decline in immune system performance with a concurrent, low-grade inflammatory state. This combination means the elderly are more prone to infections and often respond less robustly to vaccines, because the generation of new, diverse T cells declines (thymic involution) and B cell function becomes less efficient. At the same time, immune regulation can become imbalanced, increasing susceptibility to autoimmune phenomena. In this context, neutrophils and macrophages show functional declines—neutrophil chemotaxis and killing can be reduced, and macrophage phagocytosis and antigen presentation may be impaired. These changes slow the overall immune response to new pathogens and contribute to the higher infection risk seen with aging. So the description that aging increases risk for infections and autoimmune diseases while reducing neutrophil and macrophage function and slowing immune responses best reflects how the immune system changes over time. The other options—suggesting no effect, decreased infection risk, or enhanced immunity—do not align with the well-documented decline in immune competence with age.

Aging brings immunosenescence, a gradual decline in immune system performance with a concurrent, low-grade inflammatory state. This combination means the elderly are more prone to infections and often respond less robustly to vaccines, because the generation of new, diverse T cells declines (thymic involution) and B cell function becomes less efficient. At the same time, immune regulation can become imbalanced, increasing susceptibility to autoimmune phenomena.

In this context, neutrophils and macrophages show functional declines—neutrophil chemotaxis and killing can be reduced, and macrophage phagocytosis and antigen presentation may be impaired. These changes slow the overall immune response to new pathogens and contribute to the higher infection risk seen with aging.

So the description that aging increases risk for infections and autoimmune diseases while reducing neutrophil and macrophage function and slowing immune responses best reflects how the immune system changes over time. The other options—suggesting no effect, decreased infection risk, or enhanced immunity—do not align with the well-documented decline in immune competence with age.