To investigate the mechanism underlying the elevation in CD4+ T-cell counts in the CSF of patients with severe hemorrhagic stroke, we measured cytokine levels in the CSF and blood obtained from these 11 patients (Figures 4F–J), and the results demonstrated that IL-6 and IL-8 in CSF had significantly higher levels than those in the blood (median 4603.09 vs. 8.24, P < 0.001; median 665.36 vs. 7.08, P < 0.001), while the levels of other cytokines did not differ significantly. Here, CXCL8 is linked to hemorrhagic stroke.