Neutrophil Respiratory Burst: an immunological indicator of post stroke infection

Stroke is long known to be followed by a series of immunosuppressive events, and infections might be a cause of death after an acute insult of stroke. The aim of our work was to assess the percentage of neutrophils showing spontaneous oxidative burst in patients with acute ischemic stroke. The study included 30 patients with acute cerebral infarction subjected to the following: magnetic resonance imaging of the brain immediately on admission, and blood sampling on day one of admission (baseline) and after 3 days of admission. Blood samples were used for the assessment of: differential leucocyte count and percentage of neutrophils showing spontaneous oxidative burst, performed by flow cytometry. Thirty age and gender matched controls were also recruited. Neutrophil respiratory burst percentage was significantly lower in stroke patients in comparison to controls (P < 0.001), and stroke patients had significantly lower neutrophil respiratory burst percent on day 3 of admission compared to the baseline (P < 0.001). Stroke-induced immune alterations including impairment of the first-line defense performed by neutrophils against bacteria. The hypothesis that these changes enhance susceptibility to acquired infections is supported by our observation that oxidative burst in neutrophils was more impaired in patients with stroke who exhibited subsequent stroke-associated infections.