Axonal and perikaryal involvement in chronic inflammatory demyelinating polyneuropathy

Objectives-To assess the extent of loss of myelinated nerve fibres and spin al motor neuron loss in chronic inflammatory demyelinating polyneuropathy ( CIDP), a clinicopathological study was conducted on biopsied sural nerves a nd necropsied spinal cords from patients with CIDP. Methods-The myelinated fibre pathology of 71 biopsied sural nerves and moto r neuron pathology of nine necropsied spinal cords at L4 levels in patients with CIDP were quantitatively and immunohistochemically assessed. Results-Myelinated nerve fibre density was significantly diminished to 65.4 % of the control values (p <0.0001), correlating inversely with the extent of segmental demyelination and remyelination (r = -0.43, p < 0.0005) and du ration of illness (r = -0.31, p < 0.01). Numbers of large spinal motor neur ons in CIDP were variably but significantly diminished (range from 46.0 to 97.6% of the age matched control value (p < 0.005)), and reactive astroglio sis was evident in the ventral horn in CIDP. The frequency of ventral horn neurons exhibiting central chromatolysis and the accumulation of phosphoryl ated high molecular weight neurofilament protein was significantly higher i n CIDP than in controls (p<0.01 and p<0.05). Conclusions-The loss of nerve axons and spinal motor neurons is common in C IDP, and extensive in some cases. These neuronal and axonal losses may infl uence the functional prognosis in CIDP.