Incidence, risk factors and outcomes of bronchiolitis obliterans after allogeneic stem cell transplantation

Bronchiolitis obliterans (BO) after allogeneic stem cell transplantation (allo-SCT) is a late-onset, life-threatening respiratory complication that significantly reduces a patient's quality of life. We retrospectively analysed the incidence of and risk factors for BO in allo-SCT recipients. In 2087 patients who underwent allo-SCT between January 1994 and June 2005 and survived >90 days after transplantation, 57 patients developed BO with a 5-year cumulative incidence of 2.8%. The median time interval from transplantation to BO diagnosis was 335 days (range 83-907 days). The 5-year cumulative incidence of BO was 1.62% in bone marrow transplantation (BMT) from related donors, 3.83% in peripheral blood stem cell transplantation (PBSCT) from related donors (R-PBSCT), 2.91% in BMT from unrelated donors and 2.65% in unrelated cord blood transplantation. The incidence of BO after R-PBSCT was significantly higher than that after any other type of allo-SCT (p = 0.02). R-PBSCT (p = 0.019) and preceding chronic graft-versus-host disease (GVHD) (p < 0.001) were BO-associated risk factors. Overall 5-year survival of patients with BO from the time of diagnosis was 45.4%, significantly less than those without (77.5% from day 335, p < 0.001). R-PBSCT recipients with existent chronic GVHD have a high risk of developing BO, and need extensive care and repeated pulmonary function tests.