Résumé : Background and purpose: It has been suggested that inflammation may play a role in the development of cervical artery dissection (CeAD), but evidence remains scarce. Methods: A total of 172 patients were included with acute (< 24 h) CeAD and 348 patients with acute ischaemic stroke (IS) of other (non-CeAD) causes from the Cervical Artery Dissection and Ischemic Stroke Patients (CADISP) study, and 223 age- and sex-matched healthy control subjects. White blood cell (WBC) counts collected at admission were compared across the three groups. Results: Compared with healthy control subjects, CeAD patients and non-CeAD stroke patients had higher WBC counts (P < 0.001). Patients with CeAD had higher WBC counts and were more likely to have WBC > 10 000/μl than non-CeAD stroke patients (38.4% vs. 23.0%, P < 0.001) and healthy controls (38.4% vs. 8.5%, P < 0.001). WBC counts were higher in CeAD (9.4 ± 3.3) than in IS of other causes (large artery atherosclerosis, 8.7 ± 2.3; cardioembolism, 8.2 ± 2.8; small vessel disease, 8.4 ± 2.4; undetermined cause, 8.8 ± 3.1; P = 0.022). After adjustment for age, sex, stroke severity and vascular risk factors in a multiple regression model, elevated WBC count remained associated with CeAD, as compared with non-CeAD stroke patients [odds ratio (OR) = 2.56; 95% CI 1.60-4.11; P < 0.001) and healthy controls (OR = 6.27; 95% CI 3.39-11.61; P < 0.001). Conclusions: Acute CeAD was associated with particularly high WBC counts. Leukocytosis may reflect a pre-existing inflammatory state, supporting the link between inflammation and CeAD. © 2013 EFNS.