Chronic Lung Allograft Dysfunction After Lung Transplantation and Late Onset Non-infectious Pulmonary Complications After Hematopoietic Stem Cell Transplantation: Are they Mirror Images? - Abstract
Chronic Lung Allograft Dysfunction (CLAD) or chronic rejection after lung transplantation may exhibit a conventional obstructive form (bronchiolitis obliterans syndrome, BOS) or a restrictive form with predominant involvement of peripheral lung tissue (restrictive allograft syndrome, RAS). Late onset non-infectious pulmonary complications (LONIPCs) following hematopoietic stem cell transplantation typically appear as obstructive pulmonary dysfunction similar to BOS after lung transplantation, while peripheral lung tissue may also be predominantly involved. The classification and diagnosis of LONIPCs includes Idiopathic Pneumonia Syndrome (IPS), Bronchiolitis Obliterans Organizing Pneumonia (BOOP), and other conditions. Considering the interesting similarity of immunological backgrounds (i.e., the lung allograft is targeted by the host immune system or the native lung is targeted by the immune system of the graft progenitor hematopoietic cells), the lung injury observed in these two conditions appears to be a mirror image. In this article, similarities as well as differences between the two conditions are reviewed. Hopefully, this new approach comparing the two conditions will provide a better understanding of the biological mechanisms involved and ultimately lead to better preventive and therapeutic strategies in the future.