DESCRIPTION AND OUTCOMES OF A SERIES OF 21 PATIENTS WITH INTERSTITIAL PNEUMONIA WITH AUTOIMMUNE FEATURES IN A MULTIDISCIPLINARY UNIT.

Background: A significant proportion of patients with idiopathic interstitial pneumonia shows autoimmune features, but do not meet the criteria to be classified as a systemic autoimmune disease. In 2015, a joint working group of the European Respiratory Society (ERS) and the American Thoracic Society (ATS) proposed classification criteria for the category called interstitial pneumonia with autoimmune features (IPAF). Objectives: To evaluate the clinical, serological and morphological characteristics of a series of 21 patients with IPAF as well as the treatment that was applied and the evolution they presented. Methods: A retrospective cohort study was conducted. The patients who met ERS/ATC IPAF classification criteria in the period from 2012 to 2019 were collected from our interstitial lung disease (ILD) database, including 546 patients. All cases were systematically assessed in a multidisciplinary committee. Clinical, serological, morphological, as well as treatment and outcome variables were collected. A Descriptive analysis is shown. Results: 21 patients were included in the study, 12 of them (57.1%) women. The mean age at diagnosis was 61.6 years (SD 14.0), and the median follow-up time was 2.9 years (IQR 4.9). All showed ILD by HRCT, 10 (47.6%) patients had autoimmune features at the moment of the diagnosis, and 20 (95.2%) were positive for some auto-antibody. 12 (57.1%) fulfilled two of the three domains, and 9 (42.9%) fulfilled the three IPAF domains. Characteristics are described in Table 1. Lung biopsy was performed in 9 cases (42.9%). The mean FVC at diagnosis was 70.4% (DS 21.0) and DLCO 46.7% (DS 21.5). Regarding the treatment during the disease, mofetil mycophenolate (MMF) was used in 8 (38.1%) patients, cyclophosphamide (CYC) in 3 (14.3%), rituximab (RTX) in 2 (9.5%) and azathioprine in 2 (9.5%). In 1 case (4.8%), CYC and RTX were used in combination. Oral glucocorticoids (GCC) were prescribed in 14 patients (66.7%), 4 of them alone, and 6 cases (28.6%) required high-dose methylprednisolone in 250-1000 mg regimens. Antifibrotic drugs (nintedanib or pirfenidone) were used in 5 cases (23.8%) in combination with immunosuppressants and/or GCC. Five patients (23.8%) required home oxygen supplementation. Outcomes to date: 7 (33.3%) patients had readmissions due to ILD acute exacerbation; 2 (9.5%) required lung transplantations, and 3 (14.3%) died during follow-up, 1 (4.8%) due to respiratory causes. Conclusion: IPAF was more frequent in women; ANA were the prevalent antibodies; NSIP was the most repeated radiological and pathological pattern; and the combination of GC plus MMF was the most used treatment scheme. Despite our low numbers, acute exacerbations, requirement of lung transplantation and deaths have occurred, which demonstrates the severity of the disease. References: [1]Fischer A, et al. An official ERS/ATS research statement: interstitial pneumonia with autoimmune features. Eur Respir J. 2015 Oct;46(4):976–87. Disclosure of Interests: Maria del Carmen Lopez Gonzalez: None declared, ESTER NOFUENTES: None declared, Sandra Ruiz Alcaraz: None declared, Ignacio Gaya Garcia-Manso: None declared, Raquel Garcia Sevila: None declared, Paloma Vela-Casasempere: None declared, Mariano Andres Grant/research support from: Grunenthal, Consultant of: Grunenthal, Menarini, Speakers bureau: Grunenthal, Horizon