Clinicopathological study of vasculitic peripheral neuropathy

Objective To summarize the clinical features and neuropathological characteristics in patients with vasculitic peripheral neuropathy (VPN). Methods Clinical manifestations, laboratory examination and neuromuscular biopsy characteristics of 11 patients with VPN were retrospectively analyzed. The lesion of nerve, muscle and skin was observed under optical and electron microscope. Immunohistochemical analyses were carried out to detect neurofilament (NF), myelin basic protein (MBP), peripheral myelin protein 22 (PMP22) and S-100 protein (S-100) and further observing the neuropathy of neuraxon, myelin sheath and Schwann cells, and to detect human leukocyte antigen DR (HLA-DR), CD68, CD3 and CD20 to observe inflammatory cell infiltration. Immunofluorescent staining was used to detect the deposition of IgA, IgM, IgG and addiment C3 on vascular wall. The staining of periodic acid-Schiff (PAS), NADH-tetrazolium reductase (NADH-TR) and modified Gomori trichrome (MGT) were used to judge the myopathy. Results 1) Angiopathies were mainly manifested by small vessels of epineurium and perineurium, and infiltrated inflammatory cells were mainly CD3 + T cells. Three patients had active vasculitis, and 8 patients had non-active vasculitis. Among these 8 patients, 4 patients mainly presented fibrous obliteration of blood vessel, with slight inflammatroy cell infiltration, and the other 4 patients mainly showed perivascular inflammation. 2) Neuropathy: 6 patients had axon degeneration, and 5 patients had axon degeneration associated with demyelination. All of them demonstrated a reduction in myelinated fibers, mainly large diameter myelinated fibers, even on end-stage. 3) Muscle biopsy showed neurogenic atrophy. 4) Clinicopathologic diagnosis: among these 11 patients, 8 patients were diagnosed as systemic vasculitic peripheral neuropathy (SVPN), among whom 5 patients were diagnosed as primary systemic vasculitis [including 1 patient as Churg-Strauss syndrome (CSS), 2 patients as anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and 2 patients as immuno-mediated interstitial lung disease (ILD)], and 3 patients were diagnosed as secondary systemic vasculitis. The other 3 patients were diagnosed as nonsystemic vasculitic periphral neuropathy(NSVPN). Conclusions The pathological features of VPN showed that the axonal degeneration was more serious than the myelin lesions because axons were more vulnerable to ischemia than Schwann cells, perineurial cells and fibroblasts. The pathology of VPN are diverse, which are associated with the disease progression and treatment, and therefore the hemo-immunologic parameters, nerve and muscle biopsy should be checked when the VPN is suspected. doi: 10.3969/j.issn.1672-6731.2014.06.011