Fever in the elderly. Production of leukocytic pyrogen by monocytes from elderly persons.

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.