CD177 Expression on Neutrophils Predicts Ischemic Stroke Outcome in Humans

BACKGROUND: Neutrophil granulocytes actively contribute to tissue damage after ischemic stroke. The membrane protein CD (cluster of differentiation)177 is detectable on variable neutrophil numbers in most individuals (CD177 wild-type [CD177 WT ] genotype), whereas ≈5% of the general population completely lack CD177 (CD177-deficient [CD177 null ] genotype). Despite its known relevance in vasculitis, the role of ischemic stroke remains unknown. METHODS: In 2 prospective cohorts of patients with first-ever ischemic stroke (PROSCIS-B [Prospective Cohort With Incident Stroke Berlin], NOFF-S [Neutrophils: Origin, Fate & Function Stroke]), we assessed the effect of CD177 null and CD177 WT status on stroke severity and outcome (National Institutes of Health Stroke Scale and modified Rankin Scale) over 1 year or 3 months poststroke, respectively. By flow cytometry, we stratified CD177 expression level as CD177 neg , CD177 dim , and CD177 high . The predictive value of the CD177 state was evaluated by multivariable regression and discrimination analyses. RESULTS: In PROSCIS‐B (n=579; mean age, 68.1 years; 38.5% women) and NOFF-S (n=236, 68.4 years, 36.9% women), similar rates of patients were CD177 null (n=26 [4.5%] and n=10 [4.2%], respectively). Patients with CD177 null had a higher probability of unfavorable stroke outcome (modified Rankin Scale score 3–6) than patients with CD177 WT (n=8 of 21 [38.1%] versus 90 of 462 [19.5%] with follow-up, P =0.05, in PROSCIS-B; n=8 of 10 [80.0%] versus n=23 of 142 [16.2%] with follow-up, P