Association between IL-5 levels and the clinicopathological features of eosinophilic granulomatosis with polyangiitis

Objective: Eosinophilic granulomatosis with polyangiitis (EGPA) is one of the principal causes of vasculitic neuropathy. Recently, clinicopathological differences among patients with EGPA based on their anti-neutrophil cytoplasmic antibody (ANCA) status have been reported. Furthermore, the efficacy of mepolizumab (an anti-interleukin-5 (IL-5) antibody drug) for the treatment of patients with EGPA has been demonstrated. This study aimed to elucidate the significance of IL-5 on the clinicopathological features of EGPA.

Methods: The clinical features and pathological findings of sural nerve biopsy specimens from 45 patients with EGPA were examined. 

Results: Of the 45 patients, 26 (58%) exhibited elevated serum IL-5 levels, whereas 14 (31%) were positive for myeloperoxidase (MPO)-ANCA. MPO-ANCA positivity was observed more frequently in IL-5-negative patients than in IL-5-positive patients (27% vs. 37%, P = 0.5), although not statistically significant. Sural nerve biopsy revealed hig...