Differential clinicopathological features of EGPA-associated neuropathy with and without ANCA.

Objective To investigate the clinicopathologic features of eosinophilic granulomatosis with polyangiitis (EGPA)–associated neuropathy with a focus on the presence or absence of anti-neutrophil cytoplasmic antibodies (ANCAs). Methods We examined the clinical features and pathologic findings of sural nerve biopsy specimens from 82 patients with EGPA-associated neuropathy. Of these patients, 32.9% were myeloperoxidase (MPO)-ANCA positive, and 67.1% were MPO-ANCA negative. PR3-ANCA was negative in all of 78 examined patients. Results Upper limb symptoms were more frequently reported as initial neuropathic manifestations in the MPO-ANCA–positive group than in the MPO-ANCA–negative group (44.4% vs 14.6%, p Conclusions This study suggests that the pathogenesis of EGPA comprises at least 2 distinct mechanisms: ANCA-associated vasculitis resulting in ischemic effects and inflammation, which is prominent in MPO-ANCA–positive patients, and eosinophil-associated vascular occlusion leading to ischemia and eosinophil-associated tissue damage, which is conspicuous in MPO-ANCA–negative patients.