Cortisol is More Important than Metanephrines in Driving Changes in Leukocyte Counts after Stroke.

Background: There are notable changes in the number of white blood cells (WBCs) after stroke, but the primary mediators of these changes are unclear. In this study, we assessed the role of the neuroendocrine and sympathetic nervous systems in stroke-induced changes of WBCs within distinct leukocyte subsets, as well as the effect of these changes on stroke outcomes.

Methods: Patients were recruited within 72 hours after ischemic stroke; complete blood count with differential was obtained at set time points. The relationships among leukocyte numbers, cortisol, adrenocorticotropic hormone, interleukin-6, and metanephrines were assessed at 72 hours after stroke. Associations between abnormal leukocyte counts at 72 hours, poststroke infection, and 3-month outcomes were determined.

Results: A total of 114 subjects were enrolled. Severe stroke was associated with leukocytosis, neutrophilia, monocytosis, lymphopenia, and eosinopenia. At 72 hours after stroke, increased serum cortisol was independently associated with neutrophilia and lymphopenia. Abnormal leukocyte counts were not independently predictive of poststroke infection, but lymphopenia was associated with poor outcome (modified Rankin score >3) at 3 months after stroke (odds ratio = 22.86 [1.95, 267.65]; P = .01).

Conclusions: Increased serum cortisol is independently associated with neutrophilia and lymphopenia after stroke. Lymphopenia is not an independent predictor of infections but is independently associated with worse outcome.