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A1668 - Interstitial Lung Disease in ANCA-Positive Vasculitis Patients
Author Block: M. Kwon1, I. C. Mira-Avendano2, A. Khoor3, C. Rojas4, A. Abril5; 1Pulmonary and Critical Care Medicine, Mayo Clinic Florida, Jacksonville, FL, United States, 2Pulmonary Medicine, Mayo Clinic Florida, Jacksonville, FL, United States, 3Laboratory Medicine and Pathology, Mayo Clinic Florida, Jacksonville, FL, United States, 4Diagnostic Radiology, Mayo Clinic Florida, Jacksonville, FL, United States, 5Rheumatology, Mayo Clinic Florida, Jacksonville, FL, United States.
Rarely, ANCA-positive vasculitis patients are found to have interstitial lung disease (ILD). Clinical characteristics are not well known in these patients. The largest report to date is from Asia describing microscopic polyangitis (MPA) as the most common association with ILD.
By retrospective chart review of the past 10 years at Mayo Clinic Florida, we included patients with diagnoses of both ANCA-positive vasculitis and ILD (ANCA-ILD). The diagnosis of vasculitis or ILD was made by expert rheumatologists and pulmonologists. Clinical characteristics of ANCA-ILD were compared to idiopathic pulmonary fibrosis (IPF) and interstitial pneumonia with autoimmune features (IPAF). The diagnoses of IPF and IPAF were made by multidisciplinary discussion, following the latest guideline and the consensus criteria by Fischer et al., respectively.
We identified 24 ANCA-ILD patients. Among them, 14 patients had MPA, 12 patients had granulomatosis with polyangitis (GPA), and 2 patients had eosinophilic granulomatosis with polyangitis (EGPA). Half of the ANCA-ILD patients presented with vasculitis prior to ILD, predominantly MPA, while 36% of ANCA-ILD presented with ILD first, most of them with GPA. Radiographically, a usual interstitial pneumonia (UIP) pattern was the most common. Honeycombing was more common in MPA compared to GPA. Ground glass opacity was present in 5 (63%) of GPA and in 5 (36%) of MPA. Most MPA patients had positive anti-MPO antibody and p-ANCA. Only one GPA patient had positive anti-MPO antibody and two were p-ANCA positive. A majority of the GPA patients were positive for anti-proteinase-3 antibody and c-ANCA. The mainstay of treatment was corticosteroids. Rituximab was used in 14 patients. The change in functional vital capacity (FVC) and diffusing capacity (DLCO) was most marked in IPF, followed by ANCA-ILD and then the IPAF (ΔFVC, -0.5, -0.5, and 0.3 L/s; ΔDLCO, -3.7, -3.6, and -0.1 ml/min/mmHg, respectively). In a similar manner, survival was poorest in IPF, followed by ANCA-ILD and was best in the IPAF.
To our knowledge, this is the largest case series of clinically confirmed ANCA vasculitis with ILD in North America. Sizable number of GPA with c-ANCA positive patients presenting concomitant ILD is a novel observation for the clinical characteristics of ANCA-ILD that contradicts previous epidemiology of ANCA-ILD. Our data is also of value by adding prognostic information in an era of newer therapeutics, such as rituximab. In addition, the intermediate prognosis of ANCA-ILD, between IPF and IPAF, is interesting especially after the new consensus definition of IPAF.