Cellular infiltrates in skin and sural nerve of patients with polyneuropathies

Introduction: The aim of this study was to determine the diagnostic usefulness of skin punch biopsies with emphasis on visualization and quantification of T-cells and macrophages in patients with polyneuropathies. Methods: We quantified inflammatory cells in skin samples (lower leg, upper thigh) in 187 patients and compared data with counts in their sural nerve biopsies and with skin biopsies from 32 healthy volunteers. Results: Vessel-bound T-cells and macrophages were increased in proximal and distal skin samples of neuropathy patients compared with controls (P < 0.001 in both). Patients with vasculitic neuropathy had increased T-cell and macrophage counts in distal skin compared with controls (P < 0.01; for scattered macrophages/mm² diagnostic sensitivity 71% and specificity 79%). In patients with vasculitic neuropathy, distal skin perivascular inflammatory cell counts also correlated with those in sural nerve biopsies (P < 0.001). Conclusion: Neuropathy per se may lead to skin inflammation. In cases of possible vasculitic neuropathy, skin biopsy may be an additional tool to support the diagnosis. Muscle Nerve 55: 884–893, 2017.