Background: Eosinophils are involved in the pathophysiology of many respiratory diseases, but the exact role of eosinophilia in lung transplantation has not been thoroughly investigated.
Methods: We performed a retrospective analysis of our transplanted patients between 2001 and 2011, with a minimum follow-up of 1 year. Using a cutoff of ≥2% eosinophilia in bronchoalveolar lavage (BAL) fluid, chronic lung allograft dysfunction (CLAD)-free survival and overall survival was compared between 66 patients demonstrating at least one BAL with eosinophils ≥2% and 253 control patients (never BAL ≥2%).
Results: Patients with increased BAL eosinophilia demonstrated worse CLAD-free and overall survival (both P<0.0001) compared with controls. Eosinophilic BAL predisposed to development of bronchiolitis obliterans syndrome but particularly to restrictive allograft syndrome (P<0.0001). After correction for covariates, the association between eosinophilic BAL and CLAD but equally death remained significant (P=0.0047 and 0.0011). Blood eosinophil and C-reactive protein levels were also elevated at the time of eosinophilic BAL.
Conclusion: BAL eosinophilia ≥2% is associated with poor outcome in our lung transplant patients as demonstrated by worse CLAD-free and overall survival. Interestingly, increased BAL eosinophilia may be specifically associated with the development of restrictive allograft syndrome, which needs further prospective investigation.