Recurrence of Hypersensitivity Pneumonitis After Lung Transplantation

Abstract

INTRODUCTION: Lung transplantation (LT) can be a lifesaving therapy for patients suffering from advanced lung disease due to hypersensitivity pneumonitis (HP). Published data are limited addressing recipient outcomes post-lung transplantation (LT) in HP. In particular, although recurrence of primary disease in the recipient allograft has been described for a number of conditions1 this phenomenon is not well documented in HP. We present a case of recurrent HP in a LT recipient. CASE PRESENTATION: Bilateral LT was performed in 2009 on a 49-year-old woman with advanced fibrotic HP. She initially presented in 1991 complaining of cough and dyspnea, with imaging suggestive of HP and confirmation by surgical biopsy. She had no clear indoor exposure history; the possibility of ambient environmental exposures was considered. Serologic testing demonstrated precipitating antibodies to both bird proteins and fungi. Despite immunosuppressive therapy and potential ambient antigen avoidance by relocating, she had a slow decline in respiratory function and underwent bilateral LT in 2009. She did well for the first 2 years post-LT. By 3 years, however, she developed worsening cough and exertional dyspnea. She had an immune suppressive regimen of prednisone 10 mg daily, mycophenolate mofetil 500 mg bid, and tacrolimus (trough 8-10 ng/mL). CT scanning revealed air trapping; lung function testing showed a declining FEV1. Transbronchial lung biopsies (TBBX) showed non-necrotizing granulomas (culture negative). Repeat TBBXs at 1 month were unchanged. Bronchial alveolar lavage (BAL) showed 29% lymphocytes. The patient noted that pigeons were roosting outside her windows at her new home. Prednisone was increased, the patient again changed residence and her FEV1 stabilized. Subsequent TBBXs show no granulomas; the BAL lymphocytosis has resolved. She now has grade 3/3 bronchiolitis obliterans syndrome. It is unclear whether the recurrent HP contributed to this outcome. DISCUSSION: HP represents an immune reaction to inhaled organic antigens. Despite standard post-LT immunosuppressive regimens, intercurrent or ongoing exposure to an offending antigen may lead to recurrent disease in the allograft. Suggestive findings can include BAL lymphocytosis and non-necrotizing granulomas in the absence of infection. CONCLUSIONS: Our case highlights the importance of antigen recognition and aggressive avoidance or abatement post-LT for HP. This can be particularly problem-ridden if the exposure is poorly characterized. A detailed exposure history not only pre-LT but also at post-LT visits is imperative for this patient population.