Axon cytoskeleton ultrastructure in chronic inflammatory demyelinating polyneuropathy
Résumé
Introduction: To detail the extent and pattern of axon cytoskeleton alterations in chronic inflammatory demyelinating polyneuropathy (CIDP).Methods: Nerve biopsies from 7 cases of CIDP, including 4 cases with severe fiber loss, were compared with 5 controls by morphometric transmission electron microscopy (TEM).Results: Despite demyelination of single fibers, myelin ultrastructure was otherwise normal. Contrary to immunolabeling, TEM revealed a decrease in neurofilament (NF) density in every case, although there were pronounced variations among fibers even in the same sample. The NF decrease reached the same extent in large- and small-diameter fibers. It was observed in normally myelinated fibers, suggesting they were demyelinated at a distance from the section. Minimal inter-NF distance increased roughly inversely to NF density. Microtubules increased in 3 cases previously characterized by increased growth-associated protein (GAP-43) immunolabeling.Conclusion:These data demonstrate the severity and constancy of axonal lesions, and especially of NF, in residual fibers in our cases of CIDP. Muscle Nerve 44: 332–339, 2011