POS0447 INTERSTITIAL PNEUMONIA WITH AUTOIMMUNE FEATURES IS PREVALENT AMONG LUNG TRANSPLANT RECIPIENTS
Authors: E. Joerns, L. De Las Casas, A. Banga, V. Kaza, F. Torres, L. Mahan, A. Lawrence, I. Timofte, M. Mohanka, J. Joerns
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Patients with interstitial pneumonia with autoimmune features (IPAF) have interstitial lung disease (ILD) and features of autoimmunity but do not fulfill classification criteria for any of the defined rheumatic diseases (RDs) [1]. In multiple types of ILD, including IPAF, progressive pulmonary fibrosis (PPF) leads to poor quality of life and early death [2]. Lung transplant is a definitive therapy for end-stage lung fibrosis. However, we have limited knowledge regarding the prevalence of IPAF among lung transplant recipients. <h3>Objectives:</h3> To identify prevalence and recognition of IPAF among lung transplant recipients from 2019-2021 at University of Texas Southwestern Medical Center (UTSW). <h3>Methods:</h3> We identified all cases of lung transplant from 1/1/2019 to 12/31/2021 performed at UTSW. We excluded all lung transplants performed concurrently with other organ transplantation, repeat lung transplants, and transplants performed for non-ILD indications. We retrospectively reviewed charts of all remaining cases and collected demographic, serologic, clinical, radiologic, and pathological data. We classified patients with IPAF, RD-ILD, and IPF, according to published criteria [1-7]. Other etiologies of lung transplant were confirmed based on best available clinical evidence. An unclassifiable etiology was assigned if no specific interstitial lung disease could be classified or diagnosed based on chart review. <h3>Results:</h3> One hundred fourteen transplants were included in the analysis. IPAF was the most common etiology of end-stage lung fibrosis, accounting for 31% of the cases (35/114) (Table 1). Most patients with IPAF were men (74%) and the average age at transplant was 63±8 years. Seven patients were suspected to have an autoimmune related disease but only one of those patients was classified as IPAF. Ten of the 16 patients with IPAF who were treated as having IPF prior to the transplant met IPAF criteria prior to the transplant. In 6/35 of the IPAF cases, IPAF was classified after the pathological examination of the explanted native lung (Table 2). <h3>Conclusion:</h3> IPAF is a common underlying etiology of lung transplant, highlighting the risk of PPF in this population. The majority of IPAF cases were not classified as IPAF prior to this study, emphasizing under recognition of this entity in lung transplant recipients. Physicians taking care of ILD patients should be aware of high prevalence of IPAF in the population of patients undergoing lung transplant. <h3>REFERENCES:</h3> [1] Fischer A, et al. An official European Respiratory Society/American Thoracic Society research statement: interstitial pneumonia with autoimmune features. Eur Respir J. 2015;46(4):976-87. [2] Raghu G, et al. Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults: An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline. Am J Respir Crit Care Med. 2022;205(9):e18-e47. [3] van den Hoogen F, et al. 2013 classification criteria for systemic sclerosis: an American college of rheumatology/European league against rheumatism collaborative initiative. Ann Rheum Dis. 2013;72(11):1747-55. [4] Lundberg IE, et al. 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups. Ann Rheum Dis. 2017;76(12):1955-64. [5] Shiboski CH, et al. 2016 American College of Rheumatology/European League Against Rheumatism Classification Criteria for Primary Sjögren's Syndrome: A Consensus and Data-Driven Methodology Involving Three International Patient Cohorts. Arthritis Rheumatol. 2017;69(1):35-45. [6] Aletaha D, et al. 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheum. 2010;62(9):2569-81. [7] Aringer M, et al. 2019 European League Against Rheumatism/American College of Rheumatology classification criteria for systemic lupus erythematosus. Ann Rheum Dis. 2019;78(9):1151-9. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> Elena Joerns Quality improvement grant from Pfizer, Inc, for work not related to the topic of this abstract. Relationship ended in July 2022., Luis De Las Casas: None declared, Amit Banga: None declared, Vaidehi Kaza: None declared, Fernando Torres: None declared, Luke Mahan: None declared, Adrian Lawrence: None declared, Irina Timofte: None declared, Manish Mohanka: None declared, John Joerns: None declared.