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Fever in the elderly. Production of leukocytic pyrogen by monocytes from elderly persons
Abstract:
In an attempt to explain the diminished febrile response of the elderly, we studied the first step in fever generation, that of production of leukocytic pyrogen (LP) by monocytes. Monocytes from 25 healthy elderly volunteers (ages 65-91) and 24 healthy young volunteers (ages 17-38) were stimulated with Staphylococcus epidermidis to release LP; LP activity in the culture supernatants was assayed by measuring the pyrogenic response in rabbits and rats and the fall in plasma iron and zinc in rats. Monocytes from elderly volunteers produced slightly less LP than monocytes from young volunteers, but the difference was not statistically significant. The amount of LP produced was not correlated with age. Therefore, the diminished febrile response of the elderly is not the result of an intrinsic defect in the monocyte's ability to make LP. Other explanations relating to the central effect of LP and the effector response to LP in the elderly should be sought.
Insights
Elderly individuals show a reduced fever response because their monocytes produce similar amounts of leukocytic pyrogen (LP) compared to younger adults. This suggests the issue isn't with LP production but other factors.
Area of Science:
- Immunology
- Gerontology
Background:
- The elderly often exhibit a diminished febrile response to infections.
- Fever generation involves the production of leukocytic pyrogen (LP) by monocytes.
Purpose of the Study:
- To investigate if reduced LP production by monocytes contributes to the blunted febrile response in the elderly.
Main Methods:
- Monocytes from elderly (65-91 years) and young (17-38 years) healthy volunteers were stimulated with Staphylococcus epidermidis.
- Leukocytic pyrogen (LP) activity was assessed by pyrogenic response in rabbits/rats and plasma iron/zinc levels in rats.
Main Results:
- Monocytes from elderly volunteers produced amounts of LP comparable to those from younger volunteers.
- No statistically significant difference in LP production was observed between the age groups.
- LP production did not correlate with individual age.
Conclusions:
- The diminished febrile response in the elderly is unlikely due to an intrinsic defect in monocyte LP production.
- Further research should explore central LP effects and effector responses in the elderly to explain reduced fever.