AB0484 PROTEINASE 3–ANTINEUTROPHIL CYTOPLASMIC ANTIBODY (ANCA)–POSITIVE AND ANCA–NEGATIVE OR MYELOPEROXIDASE–ANCA–POSITIVE PATIENTS WITH GRANULOMATOSIS WITH POLYANGIITIS: DISTINCT PATIENT SUBSETS

Abstract

Background:Most patients with clinical diagnoses of Granulomatosis with polyangiitis (GPA) are proteinase 3 (PR3)-ANCA positive, but a significant minority are myeloperoxidase (MPO)-ANCA positive or are negative for ANCA [1]. Several clinical and genome-wide association studies have suggested that classification based on ANCA type, i.e., PR3-ANCA positivity as opposed to MPO-ANCA positivity, may be more relevant clinically than the traditional classification based on specific diagnosis [2].Objectives:To analyze demographic feature, disease manifestations and laboratory findings of patients with PR3-ANCA positive GPA in comparison with patients ANCA-negative or MPO- ANCA positive GPA.Methods:This is a retrospective analysis of 37 patients with GPA from a single center in Ukraine observed from 2010 till the end of 2019. The clinical and demographic data, initial Birmingham vasculitis activity score (BVAS/WG), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were compared between patients with PR3-ANCA positive GPA and ANCA-negative or MPO-ANCA positive GPA.Results:Of the 37 patients analyzed, 24 (64.9%) had PR3-ANCA–positive GPA, 6 (16.2%) had MPO-ANCA–positive GPA and 7 (18.9%) had ANCA-negative GPA. ANCA–negative GPA patients were younger at diagnosis compared to PR3-ANCA–positive and MPO-ANCA-positive patients (36 versus 47 and 49 years; p = 0.04). The gender ratio was similar in patients with PR3-ANCA–positive GPA and patients with MPO-ANCA–positive GPA or ANCA-negative GPA (33% vs 38% male, p= 0.61). The ocular manifestations - conjunctivitis/episcleritis (15% vs 50%) and ear involvement - otitis, mastoiditis (0% vs 33%) occurred more often in patients with PR3-ANCA–positive GPA (p<0.05), whereas sensory peripheral neuropathy (54 % vs 21%) and Raynaud’s syndrome (31 % vs 0%) were more frequent in compared group (p<0.05). ANCA-negative patients with GPA had lower, but no significant, initial BVAS/WG score than PR3-ANCA–positive or MPO-ANCA-positive patients with GPA (17.9 versus 23.5 and 24.8; p=0.20). There were no significant differences between groups in ESR or CRP levels and in the frequency of involvement of other organs and systems.Conclusion:We demonstrate clinical differences between PR3-ANCA–positive patients with GPA and MPO-ANCA–positive or ANCA-negative patients with GPA. The eye and ear involvement are common for patients with PR3-ANCA–positive GPA. The MPO-ANCA–positive GPA or ANCA-negative GPA is characterized by higher frequency of sensory peripheral neuropathy and Raynaud’s syndrome.