AB1216 INTERSTITIAL PNEUMONIA WITH AUTOIMMUNE FEATURES (IPAF): A SINGLE CENTER, PROSPECTIVE STUDY

Abstract

Background:Interstitial pneumonia with autoimmune features (IPAF)1describes a group of patients with interstitial lung disease and autoimmune features who do not meet the classification criteria for a specific connective tissue disease. Limited data regarding IPAF are available so far.Objectives:To identify the epidemiological and clinical characteristics of patients with IPAF and to observe disease progression, response to treatment and frequency of infections in 1-year follow-up period.Methods:Thirty-nine patients from ‘Attikon’ University Hospital of Athens fulfilling the IPAF criteria were enrolled. Clinical and laboratory findings, comorbidities, medications, pulmonary outcomes assessed with repeated pulmonary function tests (PFTs) and chest HRCT and complications in a 1-year follow-up period were documented for each patient. Univariate models were performed in order to identify determinants of infection and clinically significant difference in PFTs (defined as change of ≥ 10% in FVC and/or ≥ 15% in DLCO).Results:The mean age at the time of IPAF diagnosis was 63.2 (±11) years and 62% of the patients were female. The most common clinical features included in the IPAF criteria were arthritis (82%) and Raynaud’s phenomenon (26%). A morbilliform and/or polymorphic rash of the face, neck and extremities (not included in the IPAF criteria) was noted in 54% of patients. ANA (59%) and anti–Ro (21%) were the most common auto-antibodies. Non-specific Interstitial Pneumonia (NSIP) was the most prevalent radiological pattern (61.5%) as shown in table 1. Treatment comprised corticosteroids and immunosuppressants including hydroxychloroquine, methotrexate, azathioprine, mycophenolate and cyclophosphamide. PFTs following treatment at 6 and 12 months from baseline showed a trend of improvement (Table 2, p> 0.05). At 1 year from baseline, 20.5% of patients showed a clinically significant deterioration while 25% had a clinically significant improvement. Infections were observed in 23.1% of patients during the first semester and in 12.8% during the second semester of the follow-up period. All were respiratory tract infections and two patients (5.1%) required hospitalization. All infections occurred in patients with non-UIP pattern (p=0.02) which might be attributed to higher doses of corticosteroids used in these patients (mean initial prednisolone dose = 27 (±18) mg/d in patients with non-UIP pattern versus 17 (±16) mg/d in patients with UIP pattern, p=0.4).Table 1.Prevalence of HRCT patterns in 39 patients.Radiological patternNo (%)NSIP24 (61,5%)OP2 (5,1%)NSIP with OP overlap2 (5,1%)LIP1 (2,6%)UIP7 (18%)NSIP and UIP3 (7,7%)NSIP: Non-specific Interstitial Pneumonia, OP: Organizing Pneumonia, LIP: Lymphocytic Interstitial Pneumonia, UIP: Usual Interstitial Pneumonia.Table 2.PFTs at baseline, 6 and 12 months.PFTs (% of predicted value ± SD)Baseline6 months12 monthsP valueFVC79% (±19%)82% (±18%)84% (±17%)nsDLCO49% (±16%)52% (±17%)53% (±17%)nsConclusion:Rash is a common feature in IPAF and may be considered for inclusion into IPAF criteria. A trend of improvement in PFTs and a significant risk of respiratory tract infections mainly in the first semester of treatment and in patients with non-UIP radiological pattern were observed. Larger prospective studies are warranted in order to elucidate IPAF’s prognosis and to identify effective management approaches.