Background: Microscopic Polyangiitis (MPA) is an ANCA associated vasculitis (AAV), associated with p-ANCA (perinuclear) fluorescence pattern and anti- myeloperoxidase (MPO) specificity. Most frequently involved organs are kidney (80%–100%), peripheral nervous system and skin (30%). There is Pulmonary involvement in 25%–35% of patients, being alveolar haemorrhage frequently described. Interstitial lung disease (ILD) has also been recognised.

Objectives: The aim of our study is to report the characteristics of MPA Chilean patients with ILD and to compare it with other series.

Methods: Retrospective study. Patient diagnosed between 2007 and 2016 at the Hospital Clĺnico Universidad de Chile, with ILD, defined as interstitial lung disease on CT scan with Usual Interstitial Pneumonia (UIP) or Non Specific Interstitial Pneumonia (NSIP) pattern, and MPA were included. Demographic, clinical, laboratory and mortality data were plotted. Data from other series were compared with our results. Other causes that could explain the pulmonary involvement were excluded.

Results: From 94 patients with AVV, 36,1% were MPA, being 16 patients with ILD. All were Hispanic, median age 65.3 years,^32–84 female 62,5% (table 1). Common manifestations were constitutional symptoms (100%), weight loss (68,7%) and fever (68,7%). All patients had anaemia, high ESR (mean 84 mm/hr. range 33–120) and CRP (8–22 times above upper normal limit). All patients were ANCA-p and MPO positive. In 10 cases ILD was diagnosed concomitantly with MPA and in 6 was 0.5 to 15 years before. 4 patients developed pulmonary haemorrhage. Images patterns were 10 UIP and 5 NSIP. All patients received corticosteroid as induction therapy, 15 also received cyclophosphamide. One patient plasmapheresis, and one received Rituximab after a relapsed. Azathioprine was used as Maintenance therapy. Four patients died during follow-up. table 2 shows data from other worldwide region compared with our data.

Abstract AB0691 – Table 1 Caracteristic of chilean patient with ILD an MPA

Abstract AB0691 – Table 2 Caracteristic of patient with ild and MPA worldwide

Conclusions: Among chilean patients there are more females, have a more NSIP pattern, and less mortality that other worldwide series.

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Disclosure of Interest: None declared

DOI: 10.1136/annrheumdis-2018-eular.1461