Clinical features and prognosis of EGPA-associated peripheral neuropathy: a multicentre REVEAL cohort study

Peripheral neuropathy (PN) is a severe manifestation of eosinophilic granulomatosis with polyangiitis (EGPA). However, the aetiology of PN in EGPA remains unclear. This study aimed to elucidate the clinical characteristics and prognosis of patients with EGPA with PN using a multicentre database in Japan.

Newly diagnosed patients with EGPA between 2006 and 2024 were enrolled in this study. EGPA was diagnosed according to the ACR/EULAR 2022 classification criteria. Initial clinical characteristics were compared between patients with EGPA with and without PN based on BVAS ver. 3.0. The recurrence rate of PN in EGPA patients with neuropathy was also investigated, and risk factors for PN relapse were identified.

Of the 159 patients enrolled in the REVEAL cohort, 107 newly diagnosed and treatment-naïve patients with EGPA were included. MPO-ANCA was positive in 45 patients (42.1%) and 93 patients (86.9%) had PN. The levels of WBC, eosinophil granulocyte, serum immunoglobulin (Ig)G, and serum IgG4 were significantly higher in patients with EGPA with PN than in those without PN. Among them, IgG4 was the most useful clinical indicator for detecting PN in patients with EGPA. Kaplan-Meier estimator showed that 5-year relapse rate of PN among patients with EGPA with PN was 18.6%. The administration rate of intravenous cyclophosphamide (IVCY) was significantly lower in patients with relapse of PN than in those without relapse of PN.

Serum IgG4 might be a useful clinical indicator for detecting PN in EGPA and IVCY administration might be effective in preventing PN relapse.