Non-infectious pulmonary complications after haematopoietic progenitor transplantation: a diagnostic approach

Haematopoietic stem cell transplantation (HCT) is an established treatment for a wide variety of haematological diseases, both malignant and non-malignant. Infectious and non-infectious post-HCT pulmonary complications are a major cause of morbidity and mortality, with non-infectious complications becoming more prominent in recent decades as prophylaxis has led to a decrease in infectious complications. Globally, these complications can be divided into three phases (neutropenic, early and late phase) depending on their time of onset in relation to the graft. There is a growing awareness that the assessment of the patient undergoing HCT should start before the transplantation itself. It is known that total body irradiation dose, the source of HCT, myeloablative regimens or lower baseline lung function are key risk factors in the development of pulmonary complications. In general, the treatment of these entities consists of administration of corticosteroids with variable response, which highlights the need to better understand the underlying biology in order to have new drugs with more directed targets to improve the prognosis of post-HCT non-infectious pulmonary complications. In view of the limited therapeutic response mentioned above, preventive measures for patients undergoing HCT, such as conditioning of less ablative regimens or pre-selection of high-risk cases, are of paramount importance in order to mitigate the severity of these devastating pulmonary complications.