Clinical and prognostic features of Korean patients with MPO-ANCA, PR3-ANCA and ANCA-negative vasculitis.

OBJECTIVES: We reclassified Korean patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) into 3 categories of AAV including MPO-ANCA, PR3-ANCA and ANCA-negative vasculitis, and investigated clinical and prognostic features.
METHODS: We reviewed the medical records of 133 patients with microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) and eosinophilic GPA (EGPA), who had either myeloperoxidase (MPO)-ANCA, proteinase 3 (PR3)-ANCA or no ANCA, and who had ever achieved the first remission. We compared clinical manifestations, initial Birmingham vasculitis activity score (BVAS) and five factor score (FFS), and relapse rates.
RESULTS: Patients with ANCA-negative vasculitis had the youngest mean age at diagnosis (50.0 years old) among AAV categories. General, cutaneous and renal manifestations were commonly observed in MPO-ANCA vasculitis, while mucous membrane, eye, ear nose throat (ENT) and renal manifestations were often documented in PR3-ANCA vasculitis. ENT manifestation was also frequently observed in ANCA-negative vasculitis. However, there were no significant differences in pulmonary and nervous system manifestations among 3 AAV categories. There were no significant differences in cumulative relapse free survival according to the presence of MPO-ANCA or PR3-ANCA or no ANCA. Meanwhile, initial BVAS or BVAS for GPA ≥13.5 in MPO-ANCA vasculitis and initial FFS (1996) ≥1 in MPO-ANCA and ANCA-negative vasculitis were significant predictors of relapse of each AAV category.
CONCLUSIONS: Clinical manifestations varied AAV categories, and neither MPO-ANCA nor PR3-ANCA significantly affected relapse of AAV. Initial BVAS or BVAS for GPA and FFS (1996) helped to predict relapse of specified AAV categories.