Illustrated HCT noninfectious lung complications in terms of structure and peak timing after HCT. The time after HCT is shown on the x-axis (in months) with the diseases. Light blue bubbles, parenchymal processes (CRS; PERDS; CLS, capillary leak syndrome from endothelial damage; AIP; rP; DPTS; RLD). Red vessels, the endothelial processes (DAH; PVOD; PCT; TA-TMA). Green airway, airway disease (BOS). IPS, which is most often defined early post HCT, includes these diagnoses (defined by hypoxia, infiltrates, alveolar injury, and excludes later diagnoses that often do not present with these features). White box, pulmonary noninfectious diagnoses not specific to HCT (TRALI; TACO; COP; PE; PTLD), which can occur throughout the HCT trajectory. Above the table are key events occurring during HCT aGVHD and cGVHD.