Background/Purpose: To correlate the clinical characteristics of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) with myeloperoxidase (MPO)-ANCA and proteinase-3 (PR3)-ANCA, and to detect clinical characteristics of AAV in Japanese patients.

Methods: The clinical data of AAV patients from 2005 to 2014 were retrieved retrospectively. AAV patients were divided into three subgroups: MPO single positive-AAV (MPO-AAV), PR3 single positive-AAV (PR3-AAV), and double positive AAV. The clinical diagnosis was based on the European Medicines Agency Algorithm along with pathological findings. The clinical characteristics of AAV such as age, sex, organ involvement, treatment, and prognosis were evaluated and compared between MPO and PR3-ANCA.

Results: Among 165 patients positive for ANCA, 77 patients were diagnosed with MPO-AAV, 13 with PR3-AAV, 4 with double positive AAV, and 71 with non-AAV. The clinical diagnosis of MPO-AAV included microscopic polyangiitis (MPA) in 55, granulomatosis with polyangiitis (GPA) in 15, and eosinophilic granulomatosis with polyangiitis (EPGA) in 8. PR3-AAV included 10 GPA, 2 MPA, and 1 EGPA. All patients with double positive AAV were diagnosed with MPA. Patients PR3-AAV were younger than those with MPO-AAV (median age 70 vs. 55 years old, P=0.006). Involvement in the eyes (46.2% vs. 6.5%, P < 0.001), nose (53.8% vs.19.4%, P = 0.013), and ears (61.5% vs. 23.4%, P = 0.009) was higher in PR3-AAV. There was no difference in gender ratio or involvement in other organs between MPO and PR3-AAV. In both MPO and PR3-AAV, the respiratory system was most frequently involved (83.1% vs. 76.9%). The respiratory involvement in MPO and PR3-AAV included interstitial pneumonia (49.4% vs. 7.7%, P=0.004), nodular shadow (7.8% vs. 53.8%, P<0.001), alveolar hemorrhage (3.9% vs. 7.7%, P=0.47), and bronchitis (12.9% vs. 0%, P=0.191).  All AAV patients except one with MPO-AAV were treated with glucocorticoid, and immunosuppressant was added as initial remission induction therapy in 20.8% and 46.2% of the patients with MPO- and PR3-AAV, respectively. In 58.4% and 23.0% of the patients with MPO- and PR3-AAV, respectively, glucocorticoid alone was sufficient for disease-activity suppression, however, in 20.8% and 30.8% of the patients with MPO- and PR3-AAV, respectively, additional immunosuppressant was required during the course. During 2 years, the relapse rate in the patients with PR3- was higher than that in those with MPO-AAV (log-rank test, P=0.046), and COX hazard analysis revealed that PR3-ANCA showed a higher relapse rate (hazard ratio 2.54, 95% CI 0.974-6.605, P=0.057). There was no difference in the survival between patients with MPO- and PR3-AAV (log-rank test, P=0.931).

Conclusion: Unlike AAV patients in Western countries, MPO-AAV was predominant in Japan. The clinical characteristics were different between MPO and PR3-AAV. The involvement of the respiratory system was most frequent in both AAVs. In contrast to Western countries, alveolar hemorrhage was rare in Japanese, and in half of MPO-AAV patients, glucocorticoid alone was sufficient. Higher relapse rate in PR3-AAV than in MPO-AAV was similar to reports from Western countries.

---

« Back to 2014 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-clinical-characteristics-of-anti-neutrophil-cytoplasmic-antibody-associated-vasculitis-by-the-serotype-specificity-to-myeloperoxidase-and-proteinase-3/