Related Experiment Video
Updated: Aug 30, 2026

Bronchoalveolar Lavage Exosomes in Lipopolysaccharide-induced Septic Lung Injury
Published on: May 21, 2018
Exosomal programmed death-ligand 1 is associated with post-intracerebral hemorrhage pneumonia
Bin Gao1,2, Ying Zhang1,2, Nuo Cheng3
1Department of Neurology, China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
Background:
Post-stroke immunosuppression elevates the risk of stroke-associated pneumonia (SAP). Our earlier research indicated that perihematomal neuron-derived PD-L1 may play a role in peripheral immunosuppression following intracerebral hemorrhage (ICH); however, the specific carriers of PD-L1 and its potential as a predictor for SAP risk are yet to be determined.
Materials And Methods:
We hypothesize that elevated levels of exosomal PD-L1 in peripheral blood after ICH mediate immune suppression and increase the risk of SAP. This observational study aimed to investigate the levels of exosomal PD-L1 post-ICH and their relationship with SAP. In an exploratory cohort of 39 patients with ICH and 24 healthy controls and a validation cohort of 144 patients with ICH.
Results:
At admission, patients with ICH exhibited significantly increased exosome numbers in their peripheral blood, with these exosomes showing high expression of the neuronal marker neural cell adhesion molecule L1, suggesting a brain origin. Exosomal PD-L1 levels were elevated in patients with ICH compared to healthy controls and were higher in patients with SAP than those without. After adjusting for confounders, exosomal PD-L1 was confirmed to be independently associated with SAP in both the exploratory cohort and validation cohort.
Conclusions:
Brain-derived exosomes with high expression of PD-L1 are substantially released into the periphery after ICH. Elevated exosomal PD-L1 levels correlate with an increased risk of SAP.
Related Concept Videos
The Extrinsic Apoptotic Pathway
Cellular Injury IlI: Cellular Death
Overview of Cell Death
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
Cellular Injury V: Apoptosis and Autophagy
Necrosis
Morphological Manifestations of Necrosis
Necrotic cells show different types of morphological appearance depending on the type of tissue and infection. In coagulative necrosis, cells become anucleated and die, but their...
Encephalitis ll: Pathophysiology
