Comparative investigation of respiratory tract involvement in granulomatosis with polyangiitis between PR3-ANCA positive and MPO-ANCA positive cases: a retrospective cohort study

Abstract

BackgroundThe clinical characteristics of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) positive granulomatosis with polyangiitis (GPA) remain unclear, as does the difference between MPO-ANCA positive GPA and proteinase 3 (PR3)-ANCA positive GPA, especially with regard to the details of respiratory tract involvement. We investigated the differences in clinical, radiological, and histopathological features between PR3-ANCA positive GPA and MPO-ANCA positive GPA.MethodsWe retrospectively reviewed 16 patients who were newly diagnosed with GPA between December 2000 and July 2014. One patient, who was positive for both PR3-ANCA and MPO-ANCA, was excluded. Our review was based on the European Medicine Agency (EMA) algorithm.ResultsFifty-six percent of GPA patients were positive for PR3-ANCA, 38 % for MPO-ANCA, and the remaining 6 % for both. The MPO-ANCA positive group included a greater number of females (67 %). There were no statistically significant differences in laboratory data, symptoms and signs, Birmingham Vasculitis Activity Score, or CT findings between the two groups. As for upper respiratory tract involvement, the most common manifestation was paranasal sinusitis, whereas lung nodules were most common as the lower respiratory tract involvement in both groups. Although the combination therapy with prednisone and cyclophosphamide was the most common initial treatment in both groups, the relapse rate in MPO-ANCA positive cases was lower than that of PR3-ANCA positive cases (17 % and 56 %, respectively).ConclusionA high prevalence of MPO-ANCA positive GPA was noted. No significant differences in clinico-radiological findings were observed except for the prevalence of relapse between the PR3-ANCA positive cases and MPO-ANCA positive cases, suggesting that the type of ANCA may be of little help in the diagnosis of GPA. Examination for granulomatous findings in the respiratory tract is important, even in MPO-ANCA positive cases. There is a need to accumulate more cases and conduct a further investigation in the future.

Myeloperoxidase–Antineutrophil Cytoplasmic Antibody (ANCA)–Positive Granulomatosis With Polyangiitis (Wegener's) Is a Clinically Distinct Subset of ANCA‐Associated Vasculitis: A Retrospective Analysis of 315 Patients From a German Vasculitis Referral Center

“…The limited data already published on MPO ANCA–positive GPA support our observations of high prevalence of female sex, mild renal impairment, and low mortality . The comparability of published AAV studies is limited.…”

“…In a small cohort, Ono et al observed relapse rates similar to PR3‐ANCA–positive GPA and higher than MPA in MPO‐ANCA–positive GPA, but lower mortality in MPO‐ANCA–positive GPA than in MPA. In contrast, Ikeda et al described a lower relapse rate of MPO‐ANCA–positive GPA compared to PR3‐ANCA–positive GPA. The likely main reasons for the favorable outcome in both GPA cohorts are the lower rate of renal involvement, especially in patients with MPO‐ANCA–positive GPA, the lower rate of chronic and end‐stage renal disease, and the lower rate of pulmonary fibrosis.…”

“…MPO‐ANCAs are found in 2.6–9.0% of mainly European patient populations with GPA . To our knowledge, only small cohorts of patients with MPO‐ANCA–positive GPA have been described to date , mainly from eastern Asia, where MPO‐positive AAV (especially MPA) is more frequent than in northern Europe and a higher proportion of GPA patients have MPO‐ANCA . Based on clinical observations, we hypothesized that patients with MPO‐ANCA–positive GPA might form a clinically distinct subset of AAV different from both patients with PR3‐ANCA–positive GPA and those with MPO‐ANCA–positive MPA.…”

Birmingham vasculitis activity score of more than 9.5 at diagnosis is an independent predictor of refractory disease in granulomatosis with polyangiitis

“…To evaluate the ethnic difference, we searched previous studies conducted in Japan and China. However, both Japanese and Chinese previous studies reported no significant differences in pulmonary clinical features including alveolar hemorrhage between patients with MPO‐ANCA and PR3‐ANCA . The discrepancy might result from the small number of patients.…”

Myeloperoxidase–Antineutrophil Cytoplasmic Antibody (ANCA)–Positive and ANCA‐Negative Patients With Granulomatosis With Polyangiitis (Wegener's): Distinct Patient Subsets

“…The differences between classifications based on the specific AAV diagnosis as opposed to ANCA type are driven primarily by GPA patients who are MPO‐ANCA positive or ANCA negative. However, little scrutiny has been given to these GPA subsets . Based on the recent studies comparing disease type and ANCA type classifications, we hypothesized that ANCA type would be predictive of clinical manifestations and risk of relapse within the same disease subset (e.g., GPA).…”