Schwann cells and myelin in human peripheral nerve: Major protein components vary with age, axon size and pathology.

Peripheral nerve SC and myelin have varied molecular phenotypes, related to age, axon size and nerve pathology. In normal adult peripheral nerve, myelin has two different patterns of molecular composition. MBP is mostly absent from myelin around a population of intermediate-sized axons, whereas P0 is present in myelin around all axons. Denervated SCs have a molecular signature that differs from normal SC types. With acute denervation, SCs may stain for both NCAM and MBP. Chronically denervated SCs often stain for both NCAM and P0.