Bronchiolitis Obliterans After Unrelated-donor Haematopoietic Stem Cell Transplantation

Objective:Bronchiolitis obliterans (BO) occurring beyond 3 months after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has become recognized as late-onset and life-threatening noninfectious pulmonary complications, and it may reduce the recipient's quality of life. However, the pathogenesis and optimal treatment for BO are still unclear. In this study, we retrospectively analyzed the incidence, clinical characters and outcome of BO among unrelated donor allo-HSCT recipients.Method and Result:Between June 2005 and May 2009,117 patients underwent unrelated donor allo-HSCT and 98 patients who survived and were free of disease for more than 3 months after HSCT were enrolled. Among the 98 patients,14 patients (14.29%) developed BO at a median interval of 307.5 days after unrelated donor allo-HSCT (range,188-1316 days). Pulmonary function tests showed a decline in FEV1/FVC to a median interval of 0.51 (0.33-0.69) and FEV1 to 32%(17-46.2%) of predicted at BO diagnosis. Chest HRCT of BO patients showed areas of air trapping on expiratory views(71.43%), hyperinflation or bronchial dilatation (64.29%) and so on.. Most of the BO patients (57.14%) did not respond to the therapy. BO has high mortality rate of 35.71%, and pulmonary failure was the leading cause of death. The presence of chronic graft-versus-host disease (GVHD) was significantly associated with the development of BO (P=0.0019). And the conditioning regimen containing anti-thymocyte globulin (ATG) can prevent BO (P=0.02).Conclusion:more effective BO therapy is needed to improve the prognosis of Bronchiolitis obliterans。the development of BO was strongly associated with chronic GVHD, but the conditioning regimen containing ATG is a protective factor.