Blood Eosinophilia Predicts Poor Outcome in Lung Transplant Recipients

Purpose Eosinophils are associated with the onset of chronic respiratory diseases like asthma and COPD. In lung transplantation, patients with increased bronchoalveolar lavage eosinophils demonstrated a worse chronic lung allograft dysfunction (CLAD)-free survival and overall survival. We investigated the association between blood eosinophilia, graft survival and CLAD-free survival after lung transplantation. Methods A retrospective analysis was performed including all transplanted patients within our center between 2011 and 2016 (n=376). Blood eosinophils were measured as part of the routine clinical follow-up including all measurements prior to 01/06/2019. A ROC analysis was performed to define cut-offs for blood eosinophilia and patients were subsequently divided in those with high blood eosinophilia vs. those with lower eosinophilia based on the defined cut-off. All patients received oral steroids as part of their standard immunosuppressive drug regimen. Results ROC analysis revealed that the optimal threshold for blood eosinophilia is >7.85% (p=0.0026) for overall survival and >7.75% (p=0.001) for CLAD-free survival. Using a threshold of >8%, 112 patients had high blood eosinophilia and 264 had low eosinophilia (16 patients developed high eosinophilia after CLAD). Patients with blood eosinophilia >8% demonstrated worse graft survival (p=0.004) and CLAD-free survival (p=0.0076) compared to those with lower blood eosinophilia. Within the high eosinophilia group, 65 (58%) patients were diagnosed with CLAD, of which 42 (37.5%) patients had BOS and 23 (20.5%) had RAS. In the group with lower eosinophilia, 80 (30.3%) patients developed CLAD with 71 (26.9%) BOS and 9 (3.4%) RAS (p Conclusion Lung transplant recipients with high blood eosinophilia (>8%) demonstrate inferior graft survival and CLAD-free survival, specifically RAS. These findings require further research and may lead to the development of an easy to use, non-invasive marker for poor transplant outcome.