末梢神経疾患の神経病理

Modern Perspectives on Peripheral Neuropathology

近年，ニューロパチー研究の分野では，電気生理や自己抗体探索などの非侵襲的な手法が多く用いられるようになり，さまざまなニューロパチーの病態が明らかになっている。これに対して，末梢神経の標本を用いた病理学的検討が行われる機会は少なくなっているが，現代の視点から末梢神経病理所見を検討すると，以前には同じものを見ていてもわからなかったことが理解できるようになることも多い。本論ではこのような観点から，末梢神経の病理所見に関する最新の知見について概説する。

Abstract

Recent advances in genetic and antibody testing have limited pathological examination of peripheral nerve specimens. However, when examining peripheral neuropathological findings from a modern perspective, there is often an opportunity to comprehend previously unnoticed observations upon re-examining the same specimen. For example, electron microscopy studies have suggested that the components that distinguish between nodal regions and internodes play a pivotal role in the behavior of macrophages that initiate myelin phagocytosis in the demyelinating form of Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP). Conversely, some patients previously diagnosed with CIDP were found to possess distinctive mechanisms initiated by autoantibodies against paranodal junction proteins such as neurofascin 155 leading to the emergence of the concept of autoimmune nodopathy. In vasculitis, the roles of neutrophils in antineutrophil cytoplasmic antibody-associated vasculitis, eosinophils in eosinophilic granulomatosis with polyangiitis, and complements in nonsystemic vasculitic neuropathy in tissue damage have also been demonstrated when viewed from a modern perspective. Furthermore, mechanisms attributable to predominant small-fiber loss in hereditary transthyretin amyloidosis have been clarified at an ultrastructural level.