CD8A and aneurysm: Since the preliminary flow cytometry data demonstrated predominance of CD8+CD161+ cells in the CSF of patients with VSP, we performed immunostaining of histological samples previously collected from two unruptured aneurysms with the following primary antibodies: anti-human CD8 (mouse monoclonal, Cat # ab17147, Abcam, Cambridge, MA) and anti-human CD161 (rabbit polyclonal, Cat # ab197979, Abcam, Cambridge, MA).