Association Between IL-5 Levels and the Clinicopathologic Features of Eosinophilic Granulomatosis With Polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is one of the principal causes of vasculitic neuropathy.1 Recently, clinicopathologic differences among patients with EGPA based on their antineutrophil cytoplasmic antibody (ANCA) status have been reported.1–3 Furthermore, the efficacy of mepolizumab (an anti-interleukin-5 [IL-5] antibody drug) for the treatment of patients with EGPA has been demonstrated.4 IL-5 is a cytokine that is essential for eosinophil proliferation, maturation, differentiation,4–6 and survival.3 Although IL-5 is considered to be closely related to the pathogenesis of EGPA, the relationship between serum IL-5 and the clinicopathologic features of EGPA has not been determined.