NLRP3 Marks an Inflammatory Neutrophil–NETosis–Pyroptosis Network in Human Ischemic Stroke Thrombi

Background: Human ischemic stroke thrombi are increasingly recognized as biologically active immunothrombotic structures. While the NLRP3 inflammasome contributes to experimental stroke pathology, its role within human cerebral thrombi remains poorly understood. Methods: Thrombi retrieved by mechanical thrombectomy from 34 patients with acute ischemic stroke caused by large vessel occlusion were analyzed by immunofluorescence for NLRP3, ASC, neutrophils (CD66B), NETosis (H3CIT), HMGB1, and Gasdermin D. Results: NLRP3 was detected in all thrombi and correlated with neutrophil abundance, NETosis, HMGB1, and GSDMD independently of fibrin content. A majority of CD66B-positive neutrophils exhibited ASC immunoreactivity. Neither NLRP3 nor the inflammatory thrombus signature was associated with stroke severity, infarct extent, or functional outcome. Conclusions: Human ischemic stroke thrombi contain an NLRP3-associated neutrophil inflammatory network with histological evidence consistent with inflammasome assembly. This signature appears to reflect local thrombus biology rather than clinical disease severity.