The ABC of transplant: ALAD, BLAD, and CLAD: definition and significance.

Objective: Chronic lung allograft dysfunction (CLAD) is a recognized complication after lung transplantation, with a clear definition, although some pitfalls in phenotyping still exist. Recently, new terminologies, such as acute lung allograft dysfunction (ALAD) and baseline lung allograft dysfunction (BLAD) were introduced, but their definitions and real significance are not yet fully established.

Results: Based on the existing literature and ongoing discussions within two expert groups of the Advanced Lung Failure & Transplantation Interdisciplinary Network (ALFTx IDN) of the International Society for Heart and Lung Transplantation (ISHLT), we will describe current definitions, prevalence and outcome of these rather new entities, keeping in mind that a lot of uncertainties still exist.

Conclusions: ALAD and BLAD will be defined, and the currently accepted outcome of these conditions will be summarized. Existing pitfalls in the phenotyping of CLAD will also be discussed.