What can we learn from a negative randomised controlled trial in bronchiolitis obliterans syndrome after lung transplantation?

<title>Extract</title> Lung transplantation (LTx) is now a widely accepted procedure for end-stage pulmonary diseases. Nevertheless, long-term survival after LTx remains limited because of chronic lung allograft dysfunction (CLAD), which is mainly manifested as bronchiolitis obliterans syndrome (BOS), accounting for approximately 80% of CLAD cases [1]. The definition of BOS was first introduced in 1993 by an <italic>ad hoc</italic> working group of the International Society of Heart and Lung Transplantation (ISHLT), with the aim of developing a clinically applicable and standardised method for assessing functional results after LTx [2].