Air-leak syndrome following allo-SCT in adult patients: report from the Kanto Study Group for Cell Therapy in Japan.

We retrospectively investigated air-leak syndrome (ALS), including pneumothorax and mediastinal/s.c. emphysema, following allogeneic hematopoietic SCT. Eighteen patients (1.2%) developed ALS among 1515 undergoing SCT between 1994 and 2005 at the nine hospitals participating in the Kanto Study Group on Cell Therapy. The median onset of ALS was at 575 days (range: 105-1766) after SCT and 14 patients (77.8%) had experienced late onset noninfectious pulmonary complications (LONIPC) before ALS. Chronic GVHD (cGVHD) was the strongest risk factor for ALS (odds ratio 13.5, P=0.013 by multivariate analysis). Repeat SCT, male sex and age <38 years at the time of transplantation were also significant risk factors for ALS. Patients with ALS had a significantly worse survival rate than those without ALS (61.5 vs 14.9% at 3 years; P=0.000). The main cause of death was respiratory complications in 8 of the 18 patients. In conclusion, ALS is a rare complication of SCT that is more likely to occur in relatively young male patients with cGVHD and/or LONIPC. It is possible that better understanding and treatment of LONIPC may lead to prevention of ALS.