Involvement of cell-mediated immunity in the pathogenesis of CIDP is supported by evidence that activated T cells cross the blood-nerve barrier and that various T cell associated cytokines such as TNFα, IFNα and IL-2 are expressed in abundance in the perineurium, endoneurium and endoneurial blood vessels in patients with CIDP (101). Here, TNF is linked to chronic inflammatory demyelinating polyradiculoneuropathy.