AUTHOR=Liu Suying , Han Linna , Liu Yanhui , Yang Jun , Zhang Yu , Li Mengtao , Tian Xinping , Zeng Xiaofeng , Wang Li , Zhang Fengchun 

TITLE=Clinical Significance of MPO-ANCA in Eosinophilic Granulomatosis With Polyangiitis: Experience From a Longitudinal Chinese Cohort

JOURNAL=Frontiers in Immunology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.885198

DOI=10.3389/fimmu.2022.885198

ISSN=1664-3224

ABSTRACT=Objectives. To investigate the clinical significance of myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA) on eosinophilic granulomatosis with polyangiitis (EGPA) from a longitudinal Chinese cohort.
Methods. A total of 120 patients with EGPA were consecutively enrolled and followed up. Two patients with PR3 ANCA was excluded and our analysis focused on the 118 EGPA patients. Based on MPO-ANCA status, baseline clinical manifestations, treatment, and outcomes were analyzed. Logistic regression analysis was performed to analyze the independently associated factors for renal involvement. 
Results. ANCA positivity was observed in 24.2% of EGPA patients. Patients with MPO-ANCA accounted for 20.8%. MPO-ANCA-positive patients had higher levels of erythrocyte sedimentation rate (ESR), C-reactive protein, Birmingham Vasculitis Activity Score (BVAS), higher ratios of fever, myalgia, renal involvement, and biopsy-proven vasculitis. Heart manifestations and asthma were more common in ANCA-negative patients. Baseline MPO-ANCA titers positively correlated with ESR, eosinophil count, BVAS, and were higher in patients with methylprednisolone pulse. Among patients with renal involvement, MPO-ANCA-positive patients had higher proportions of female, fever, biopsy-proven vasculitis, and faster ESR; ANCA-negative patients developed more skin and cardiac involvement. MPO-ANCA positivity, male, and ear involvement were the independent factors associated with renal involvement. Intravenous cyclophosphamide and immunoglobulins were prescribed more frequently in MPO-ANCA-positive patients. 
Conclusion. In this cohort, MPO-ANCA-positive and ANCA-negative patients displayed distinct clinical features, suggesting MPO-ANCA might be a valuable biomarker for EGPA stratification. Baseline MPO-ANCA level correlated positively with disease activity of EGPA. MPO-ANCA was  a significant independent factor associated with renal involvement.