“…In many PNS diseases, even in non-in¯ammatory PNS diseases like hereditary polyneuropathy, ischemic neuropathy or axonal degeneration after sciatic nerve transection, mononuclear cell in®ltration is involved during the development of pathological changes (Cornblath et al, 1990;Venezie et al, 1995). Since CK play a pivotal role in leukocyte traf®cking into the CNS (Proost et al, 1996;Baggiolini, 1998), it has been hypothesized that they play a similar role in the PNS (Adamus et al, 1997;Eng et al, 1996;Godiska et al, 1995;Karpus et al, 1995;Glabinski et al, 1997;Ransohoff et al, 1996). The PNS is comprised of relatively fewer cell elements than the CNS: Schwann cells, peripheral nerve axons, ®broblasts, endothelia, pericytes and macrophages (Thomas et al, 1993).…”