Clinical utility of bronchoalveolar lavage cell phenotype analyses in the postoperative monitoring of lung transplant recipients.

Abstract

Bronchoalveolar lavage (BAL) fluid provides a crucial tool for investigation of the cellular component of the deep lung spaces and hence to approach the alloreactive response following lung transplantation. This study investigated whether BAL cell profiles can assist for the diagnosis of certain postoperative complications. We conducted a retrospective analysis of both transbronchial biopsy and bronchoalveolar lavage materials in a series of 26 consecutive lung transplant recipients (LTR) in relationship with their clinical status at the time of the procedure. BAL fluid was subjected to cell morphology as well as flow cytometric phenotypic analyses. The samples were labeled as follows: normal transplant in clinically stable and healthy recipients, n=58; acute rejection (AR), n=58; infection (INF), n=31; and obliterative bronchiolitis/bronchiolitis obliterans syndrome (OB/BOS) n=27. Total BAL cell counts were the highest in INF. Lymphocytic alveolitis was suggestive of both acute allograft rejection and CMV viral infection, with a combined significant increased HLA-DR positive cells in AR. Alveolar neutrophilia with an increased CD4/CD8 ratio was correlated with the diagnosis of OB. The neutrophil percentages, HLA-DR and CD57 positive cells were significantly higher when an infection was present. These findings suggest that BAL cell analysis could give complementary information of histological data and further insight into immunologic events after lung allograft. A longitudinal surveillance of BAL cell profiles in an individual patient may be suggestive for a preclinical state of posttransplant acute rejection, bacterial infection and obliterative bronchiolitis.