Analysis of lymphocyte subsets in patients with stroke and their influence on infection after stroke

Background and Purpose-Recent studies have attributed the increased infection vulnerability of patients with stroke to stroke-induced immunosuppression. We have therefore explored the immunological changes in patients with ischemic stroke. Methods-Blood from 46 patients with stroke was analyzed by fluorescent-activated cell sorter to determine leukocyte subsets. To identify changes that represent clinically relevant immunosuppression, we compared patients who developed infection within 14 days after stroke with those who did not. Results-Stroke induced a dramatic and immediate loss of T-lymphocytes, most pronounced within 12 hours after stroke onset. Only patients with subsequent infection exhibited a delay in the recovery of CD4+ T-lymphocyte counts. Conclusions-Our data suggest that a loss of CD4+ T cell function contributes to the stroke-induced immunosuppression. The CD4+ T cell count on the day after stroke may emerge as a predictive marker for poststroke infection allowing, early identification of patients at risk.