Lung transplantation for hypersensitivity pneumonitis

Abstract

Background: Hypersensitivity pneumonitis (HP) is an inhaled antigen-mediated interstitial lung disease (ILD). Advanced disease may necessitate the need for lung transplantation. There are no published studies addressing lung transplant outcomes in HP. We characterized HP outcomes compared with referents undergoing lung transplantation for idiopathic pulmonary fibrosis (IPF).

Methods: To identify HP cases, we reviewed records for all ILD lung transplantation cases at our institution from 2000 to 2013. We compared clinical characteristics, survival, and acute and chronic rejection for lung transplant recipients with HP to referents with IPF. We also reviewed diagnoses of HP discovered only by explant pathology and looked for evidence of recurrent HP after transplant. Survival was compared using Kaplan-Meier methods and Cox proportional hazard modeling.

Results: We analyzed 31 subjects with HP and 91 with IPF among 183 cases undergoing lung transplantation for ILD. Survival at 1, 3, and 5 years after lung transplant in HP compared with IPF was 96%, 89%, and 89% vs 86%, 67%, and 49%, respectively. Subjects with HP manifested a reduced adjusted risk for death compared with subjects with IPF (hazard ratio, 0.25; 95% CI, 0.08-0.74; P = .013). Of the 31 cases, the diagnosis of HP was unexpectedly made at explant in five (16%). Two subjects developed recurrent HP in their allografts.

Conclusions: Overall, subjects with HP have excellent medium-term survival after lung transplantation and, relative to IPF, a reduced risk for death. HP may be initially discovered only by review of the explant pathology. Notably, HP may recur in the allograft.

Figure 1 –

Identification of subjects with HP and IPF. Group “D” = UNOS listing group diagnosis code for restrictive lung disease; HP = hypersensitivity pneumonitis; IPF = idiopathic pulmonary fibrosis; LT = lung transplant; UNOS = United Network for Organ Sharing.

Figure 2 –

Survival after lung transplantation for HP compared with IPF. Kaplan-Meier plot stratifying patients who underwent lung transplant for HP or IPF. The outcome was death or retransplant during the study period. See Figure 1 legend for expansion of abbreviations.

Figure 3 –

Freedom from BOS for HP compared with IPF. Kaplan-Meier plot stratifying patients who underwent lung transplantation for HP or IPF. The outcome was freedom from BOS. The total number at risk excludes nonsurvivors. BOS = bronchiolitis obliterans syndrome. See Figure 1 legend for expansion of other abbreviations.