Substance P immunoreactive astrocytes are present in multiple sclerosis plaques.

Substance P (SP)-like immunoreactive cells were identified in postmortem white matter tissue from patients with multiple sclerosis (MS). Labelled cells, which by morphologic criteria could be identified as astrocytes, were located at the edge of both active (e.g. inflammatory) and inactive (e.g. non-inflammatory) MS lesions. By contrast, SP-immunoreactive astrocytes were not found in normal controls and were only occasionally present in other conditions associated with astrogliosis. These data suggest that SP, a potent mediator of vasodilatation and local immune responses, may play a role in the genesis of the MS plaque. These results also extend the repertoire of potential interactions which may occur between astrocytes and cells of the immune system.