Antifibrotic Response in a Patient With Chronic Hypersensitivity Pneumonitis Without Antigen Removal

Abstract

SESSION TITLE: Diffuse Lung Disease SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Pirfenidone and nintedandib are anti-fibrotic agents approved by the FDA for the treatment of patients with idiopathic pulmonary fibrosis (IPF). These agents are also currently being studied in non-IPF patient populations, including systemic sclerosis associated interstitial lung disease (ILD) and fibrotic non-IPF ILD. Chronic hypersensitivity pneumonitis (CHP) is a fibrotic ILD that is often progressive in the absence of antigen removal. Here we present a case of progressive CHP while being treated with pirfenidone. CASE PRESENTATION: An 81 year-old man with minimal remote smoking history presents to outside clinic with eight years of progressive breathlessness and dry cough. His chest computed tomography (CT) demonstrated upper lobe predominant reticulation with areas of ground glass and mosaic attenuation. Clincal diagnosis of IPF was made and he was started on pirfenidone in early 2014. Over the next two years the patient developed an increasing oxygen requirement, requiring ten liters of supplemental oxygen with ambulation by late 2016. His forced vital capacity dropped from 2.6 liters (71% predicted) to 1.9 liters (53% predicted) over that same timeframe. He was referred to the UC-Davis ILD program where he underwent a high-resolution CT that again showed the findings above and a bronchoalveolar lavage that demonstrated 27 percent lymphocytes. An exposure history revealed an extensive amount of mold in his home. We made a diagnosis of CHP during a formal multidisciplinary discussion. The patient promptly relocated from his house and was started on prednisone, which resulted in symptomatic improvement and pulmonary function stabilization. DISCUSSION: Despite the overlap of some clinical, radiographic and histologic features, IPF is driven primarily by fibrotic pathways in response to alveolar epithelial injury, whereas CHP is driven by inflammatory pathways in response to inhaled antigen. Antigen identification and removal is of paramount importance in CHP, as the failure to remove the causative antigen can lead to progressive fibrotic disease similar to that of IPF. While anti-fibrotic therapy has demonstrated efficacy in patients with IPF, the role for this in other fibrotic ILDs remains undefined. CONCLUSIONS: Our case highlights the importance of antigen removal in fibrotic CHP, as the disease progressed despite anti-fibrotic therapy. Reference #1: Am J Respir Crit Care Med Vol 186, Iss. 4, pp 314-324, Aug 15, 2012 Reference #2: Curr Opin Pulm Med 2015, 21:171-177 DISCLOSURE: The following authors have nothing to disclose: Samuel Bullick, Justin Oldham No Product/Research Disclosure Information