Abstract 5504: Transient Decrease in Circulating Dendritic Cell Precursors After Acute Stroke - Potential Recruitment Into the Brain
Background: The role of dendritic cells (DC) as potent mediators of inflammation has not been sufficiently investigated in stroke.
Methods: Circulating myeloid (mDCP), plasmacytoid (pDCP), and total DCP (tDCP) were flow cytometrically analyzed in
healthy controls (n=29), patients with
asymptomatic A. carotis interna stenosis (ACI-S, n=46),
transient ischemic attack (TIA, n=39),
acute ischemic stroke (AIS, n=73), and
acute hemorrhagic stroke (AHS, n=31).
The National Institutes of Health Stroke Scale (NIHSS) and the infarction size in CT scan were evaluated after stroke. In a patient subgroup, postmortem immunohistochemical brain analyses were performed to detect mDC (CD209), pDC (CD123), T cells (CD3), and HLA-DR.
Results: In AIS and AHS, circulating mDCP, pDCP, and tDCP (each p<0.005) were significantly reduced. A significant inverse correlation was found between the NIHSS and circulating DCP (p<0.02), as well as between hsCRP and circulating DCP (p<0.001). Patients with large stroke size in CT scan had significantly lower mDCP, pDCP, and tDCP (each p<0.01) than those with smaller stroke. Follow-up analysis showed a significant recovery of circulating DCP in the first days after stroke. In the infarcted brain, a dense infiltration of mDC colocalized with T cells, single pDC, and high HLA-DR expression were observed.
Conclusions: Acute stroke leads to a decrease in circulating DCP. Potentially, circulating DCP are recruited from the blood into the infarcted brain, and probably trigger cerebral immune reactions there.