EDITORIAL Obliterative bronchiolitis in haematopoietic stem cell transplantation: can it be treated?

llogeneic and autologous haematopoietic stem cell (HSC) transplantation are now both established as principal forms of treatment for patients with acute or chronic leukaemia, aplastic anaemia and various immuno-deficiency syndromes, as well as various nonhaematological malignancies and auto-immune disorders [1–3]. However, major limitations to the successful use of HSC transplantation include respiratory complications and graft versus host disease. Lung dysfunction occurs in up to 50 % of subjects after HSC transplantation, and pulmonary complications are among the most common causes of morbidity and mortality after this procedure [4]. Obliterative bronchiolitis (OB) is the most common noninfec-tious respiratory complication after HSC transplantation [5, 6], and usually develops as a late complication (after the first 10