Bronchiolitis obliterans after allo-SCT: clinical criteria and treatment options.

Bronchiolitis obliterans (BO) following allogeneic haematopoietic SCT (HSCT) is a serious complication affecting 1.7-26% of the patients, with a reported mortality rate of 21-100%. It is considered a manifestation of chronic graft-versus-host disease, but our knowledge of aetiology and pathogenesis is still limited. Diagnostic criteria are being developed, and will allow more uniform and comparable research activities between centres. At present, no randomised controlled trials have been completed that could demonstrate an effective treatment. Steroids in combination with other immunosuppressive drugs still constitute the backbone of the treatment strategy, and results from our and other centres suggest that monthly infusions of high-dose pulse i.v. methylprednisolone (HDPM) might stabilise the disease and hinder progression. This article provides an overview of the current evidence regarding treatment options for BO and presents the treatment results with HDPM in a paediatric national HSCT-cohort.