The study was approved by the Institutional Review Board, and informed consent of patients was obtained. A total of 145 intracranial Background and Purpose-Ischemic stroke of undetermined cause is a major health issue because of its high frequency and clinical relevance. Histopathologic analysis of human thrombi, retrieved from stroke patients with large-vessel occlusion during mechanical thrombectomy, may provide information about underlying pathologies. This study examines the relationship between stroke causes and histological clot composition to identify specific patterns that might help to distinguish causes of cryptogenic stroke. Methods-Thrombi of 145 consecutive stroke patients with large-vessel occlusion were collected during intracranial mechanical recanalization. The hematoxylin and eosin-stained specimens were quantitatively analyzed in terms of the relative fractions of the main constituents (red and white blood cells and fibrin/platelets). These data, along with additional clinical and interventional parameters, were compared for different stroke subtypes, as defined by the international Trial of Org 10172 in Acute Stroke Treatment criteria. Results-The composition of thrombi from cardioembolic and noncardioembolic stroke patients differed significantly for all main thrombus components. Cardioembolic thrombi had higher proportions of fibrin/platelets (P=0.009), less erythrocytes (P=0.003), and more leucocytes (P=0.035) than noncardioembolic thrombi. Cryptogenic strokes showed strong overlap with cardioembolic strokes but not with noncardioembolic strokes, in terms of both thrombus histology and interventional and clinical outcome parameters. Conclusions-Quantitative evaluation of thrombus composition may help to distinguish between different stroke causes.Our findings support the notion that the majority of cryptogenic strokes are cardioembolic.

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Cholera toxin (CT) elicits a mucosal immune response in mice when used as a vaccine adjuvant. The mechanisms by which CT exerts its adjuvant effects are incompletely understood. We show that protection against inhalation anthrax by an irradiated spore vaccine depends on CT-mediated induction of IL-17-producing CD4 Th17 cells. Furthermore, IL-17 is involved in the induction of serum and mucosal antibody responses by CT. Th17 cells induced by CT have a unique cytokine profile compared with those induced by IL-6 and TGF-β, and their induction by CT requires cAMP-dependent secretion of IL-1β and β-calcitonin gene-related peptide by dendritic cells. These findings demonstrate that Th17 cells mediate mucosal adjuvant effects of CT and identify previously unexplored pathways involved in Th17 induction that could be targeted for development of unique mucosal adjuvants.IL-17 | dendritic cell | T cell | vaccine | cAMP

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We explored the physiological role of conventional dendritic cells (cDCs) in acute colitis induced by a single cycle of dextran sodium sulfate administration. Depending on their mode of activation and independently of T cells, cDCs can enhance or attenuate the severity of dextran sodium sulfate-induced colitis. The latter beneficial effect was achieved, in part, by IFN-1 induced by Toll-like receptor 9-activated cDCs. IFN-1 inhibits colonic inflammation by regulating neutrophil and monocyte trafficking to the inflamed colon and restraining the inflammatory products of tissue macrophages. These data highlight a novel role of cDCs in the regulation of other innate immune cells and position them as major players in acute colonic inflammation.colitis ͉ Toll-like receptor 9 ͉ IFN-1