Cytokines, first described as products of the cells of the inflammatory/immune system, are increasingly recognised as acting on non-inflammatory cells as well as being produced by non-inflammatory cells. Nowhere is this more apparent than with cells of the peripheral (PNS) and central (CNS) nervous systems. Studies have clearly indicated that neuroglial cells are targets of cytokines produced by infiltrating immune/inflammatory cells in inflammatory diseases of the PNS and CNS, and are not simply passive targets of lytic destructive processes. In addition there is evidence to show that neuroglial cells, in particular astrocytes, Schwann cells and microglia (cells of the monocyte/macrophage lineage), respond to cytokines by changes in function and phenotype and can themselves produce many of the classically described inflammatory cell cytokines. Perhaps even more interesting are recent studies showing that such cytokines, particularly when produced by cells that are endogenous to the PNS and CNS, are important in PNS and CNS development and perhaps in protection and regeneration of the PNS and CNS in inflammatory, traumatic and even some degenerative diseases.
We and others have been interested in the interactions of Schwann cells and cytokines in the pathogenesis of diseases, modulation and recovery from disease, and regeneration, as well as in normal PNS development and function. Schwann cell–cytokine interactions can be studied in various ways: examining tissue obtained at different stages of development, and at different phases of experimental and naturally occurring diseases, including human disorders of the PNS, and employing different in vitro models.