Serum-induced demyelination: an electrophysiological and histological study

Serum from rabbits with EAN in the acute phase of the disease has been injected into rat sciatic nerve, and compared to control rabbit serum and serum from patients with demyelinating neuropathy and to normal human control serum. Electrophysiological studies were performed on all rat sciatic nerves so injected, and the nerve was then removed and examined histologically. Control rabbit and human serum and neuropathic human serum, when injected in a 20 microL quantity through a 30 gauge needle, did not produce significant electrophysiological abnormalities. EAN serum, however, produced significant dispersion of the muscle action potential and conduction block. All serum produced some histological evidence of demyelination but that seen with EAN serum was quite profound compared to all other sera. It is concluded that humoral factors are present within animals with EAN which has potent demyelinating potential. We were not able to demonstrate the same effect from patients with demyelinating neuropathy in this test system.