Lung transplantation outcomes of patients with interstitial pneumonia with autoimmune features: a single-centre retrospective cohort study.

Abstract

Interstitial pneumonia with autoimmune features (IPAF) describes patients with interstitial lung disease (ILD) and autoimmune features without meeting criteria for a specific rheumatic disease. No longitudinal data exist on post-transplant outcomes in IPAF patients. We compared baseline demographics, pre-transplant characteristics and post-transplant outcomes between IPAF and idiopathic pulmonary fibrosis (IPF) patients undergoing double lung transplantation. We retrospectively analysed lung transplant recipients with ILD in British Columbia between 1 January 2014 and 30 April 2024. Diagnoses of IPAF and IPF were made by multidisciplinary review. Continuous variables were analysed using the Mann-Whitney U test, categorical variables with Fisher's exact test, and survival using Kaplan-Meier analysis. We identified 20 IPAF and 64 IPF patients. IPAF patients were more likely female (50% vs 17%, P = 0.006), on pre-transplant immunosuppression (60% vs 6.3%, P < 0.001) and were less likely to receive antifibrotics (20% vs 64%, P < 0.001). No difference was seen in 1-year or cumulative survival, though survival curves diverged over time favouring IPAF. Post-transplant lung function, acute rejection, infection-related hospitalization, malignancy and chronic lung allograft dysfunction (CLAD) were similar, with non-usual interstitial pneumonia (UIP) IPAF exhibiting a survival advantage over IPF (100% vs 66%, P = 0.044). Explant pathology revealed more UIP patterns in IPF, while IPAF showed more non-specific interstitial pneumonia (NSIP) or unclassifiable patterns. Post-transplant survival, lung function and complication rates were comparable between IPAF and IPF patients at one year and the last follow-up. This is the first study to report both short- and long-term lung transplant outcomes in IPAF patients.