Neural mechanisms in the pyrogenic and acute-phase responses to interleukin-1

It has become increasingly apparent over the past several decades that the hypothalamus, among other brain regions, plays an important part in the modulation of the immune system (reviewed in Korneva et al., 1985; Roszman & Brooks, 1985; Jankovic & Spector, 1986; Cotman et al., 1987). Since the hypothalamus also mediates the fever and various other acute-phase responses characteristic of the early stages of infection (reviewed in Hellon & Townsend, 1983; Blatteis, 1984, 1985; Cooper, 1987), it is possible that the localization within a common brain region of the controllers of several, different host defense reactions is not a happenstance, but represents a highly organized neuronal network serving to coordinate them. Indeed, pyrogenic, inflammatory, and immune responses do interact in the defense of the host against infection (reviewed in Dinarello, 1984). It is not yet known how immune responses are integrated centrally, but some data are available on the neural mechanisms controlling fever and certain components of the acute-phase reaction. The purpose of this paper is to review these briefly in the hope that a background can be provided against which features that may be common to neuroimmunomodulation and to the control of acute-phase reactions might be revealed.