Value of Screening Spirometry for Early Diagnosis of Bronchiolitis Obliterans Syndrome in Children After Allogeneic Hematopoietic Stem Cell Transplantation.

Bronchiolitis obliterans syndrome (BOS) is a chronic graft-versus-host disease that occurs in the lungs after hematopoietic stem cell transplantation (HSCT). Serial screening pulmonary function test (PFT) is recommended after transplantation for early diagnosis of BOS. However, little is known about the value or the optimum methods of serial PFT in this context. One hundred and 10 consecutive patients of 6 to 17 years of age at the time of transplantation who underwent allogeneic HSCT were recruited for this study. Screening PFTs were performed 1 week before transplantation and 3, 6, 9, and 12 months after transplantation. When findings of obstructive lung disease were found on PFT, chest high-resolution computed tomography was performed. Of the 110 patients, 5 (4.5%) developed BOS. Of the 5 patients who developed BOS, 2 patients were diagnosed early by screening PFT. However, screening PFT did not allow for early diagnosis of BOS in the other 3 patients because BOS developed after 12 months of transplantation, which is beyond the PFT screening period. In conclusion, trimonthly PFTs performed through 12 months after transplantation in patients who underwent allogeneic HSCT helped in the early diagnosis of BOS; however, there are some limitations to this screening protocol. Future studies will aid in the development of a new screening protocol that can subsequently be evaluated.