Background/Purpose: Eosinophilic granulomatosis with polyangiitis (EGPA) is characterized by the preceding history of type I allergic disorders, mostly bronchial asthma, followed by the development of vasculitis affecting mainly peripheral nervous system. Whereas MPO-ANCA is detected in approximately 60% of patients with EGPA, its relationship with clinical manifestations remains unclear. We carried out a retrospective cohort study on patients in Tokyo metropolitan area to compare the clinical features between MPO-ANCA positive and negative EGPA.

Methods: All the patients fulfilled the diagnostic criteria for EGPA of the Japanese research committee of intractable vasculitis. Certificated medical records for application of medical subsidy between 2007 and 2010 were reviewed.

Results: A total of 131 patients were collected, aged 59.3 ± 15.9 years (Mean ± SD) (47 males, 84 females). The preceding allergic symptoms were bronchial asthma with or without allergic rhinitis in 96.9%, and allergic rhinitis alone in 3.1%. Peripheral neuropathy (mostly mononeuritis multiplex) was observed in 96.9%. MPO-ANCA was positive in 53 patients (40.4%). There were no significant differences in ages and gender between MPO-ANCA (+) patients and MPO-ANCA (-) patients. As to the vasculitic manifestations, arthritis and glomerulonephlitis were more prevalent in MPO-ANCA (+) patients than in MPO-ANCA (-) patients (32.1% vs 17.9% [p=0.0612] and 24.5% vs 2.6% [p=0.0001], respectively, whereas there were no significant differences in frequencies of other manifestations, including purpura, fever, body weight loss, gastrointestinal bleeding, and cardiopulmonary involvement. Peripheral blood eosinophil counts and serum rheumatoid factors were significantly higher in MPO-ANCA (-) patients than in MPO-ANCA (+) patients, whereas there were no significant differences in white blood cell counts, platelet counts and serum IgE. Cyclophosphamide appeared to be administered more frequently in MPO-ANCA (+) patients than MPO-ANCA (-) patients (54.7% vs 48.7% [p=0.0710]), whereas there were no significant differences in the use of steroid pulse therapy (54.7% vs 48.7% [p=0.5937]).

Conclusion: The results underscore the differential features between MPO-ANCA (+) and MPO-ANCA (-) EGPA, especially the higher prevalence of arthritis and glomerulonephritis in the former. Thus, the data indicate that MPO-ANCA (+) EGPA has features comparable to microscopic polyangiitis, although further studies are needed to delineate the mechanisms of differences in eosinophil counts and rheumatoid factors.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/differential-characteristics-of-mpo-anca-positive-and-negative-eosinophilic-granulomatosis-with-polyangiitis/