The facts that nearly all of the p75 NTR -expressing cells were found in close vicinity to a possible entry point for PNS-resident Schwann cells, and that they clearly resemble normal Schwann cells morphologically might suggested that this CNS population of p75 NTR -expressing cells is most probably constituted by invading Schwann cells originating from the PNS. No immunoreactivity was present within the adjacent normally appearing neuroparenchyma.
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