Epidermal nerve fiber density in sensory ganglionopathies: Clinical and neurophysiologic correlations

We assessed the involvement of somatic unmyelinated fibers in sensory gangl ionopathies by skin biopsy and quantitative sensory testing (QST). Sixteen patients with ganglionopathy, 16 with axonal neuropathy, and 15 normal cont rols underwent skin biopsy at the proximal thigh and the distal leg. Intrae pidermal nerve fibers (IENF) were immunostained by anti-protein gene produc t 9.5, and their linear density was quantified under light microscopy. Conf ocal microscopy studies with double staining of nerve fibers and basement m embrane were also performed. Healthy subjects and neuropathy patients showe d the typical proximodistal gradient of IENF density; in neuropathies, valu es were significantly lower at the distal site of the leg, confirming the l ength-dependent loss of cutaneous innervation. Conversely, ganglionopathy p atients with hyperalgesic symptoms did not show any change of IENF density between the proximal thigh and the distal leg. The distinct pattern of epid ermal denervation seen in sensory ganglionopathy reflected the degeneration of somatic unmyelinated fibers in a fashion that was not length-dependent, which was consistent with both clinical and neurophysiologic observations and supported the diagnosis. (C) 2001 John Wiley & Sons, Inc.