Varicella zoster virus vasculopathy: clinical features and pathogenesis.

Varicella zoster virus (VZV) vasculopathy is caused by productive virus infection of cerebral arteries, leading to inflammation, pathological vascular remodeling, and ischemic or hemorrhagic stroke. VZV vasculopathy occurs in immunocompetent and immunocompromised individuals and involves both large and small vessels. MRI abnormalities include more deep-seated than superficial lesions, particularly at gray-white matter junctions, and lesions may enhance. Diagnosis is challenging, since stroke can occur months after zoster rash and in the absence of rash or CSF pleocytosis. The best virological test for diagnosis is detection of anti-VZV IgG antibody in the CSF. Pathological studies of VZV-infected arteries from patients with VZV vasculopathy reveal that the arterial adventitia is the initial site of infection, after which virus spreads transmuraly towards the lumen. Histological and immunohistochemical studies of VZV-infected arteries show a thickened intima, disrupted internal elastic lamina, and loss of smooth muscle cells, that likely contribute to weakening of the vessel wall and occlusion. Early in disease, VZV-infected arteries contain CD4+ and CD8+ T cells, macrophages, and rare B cells, in addition to abundant neutrophils in early disease. Importantly, perivascular inflammatory cells underlie the areas of thickened intima, raising the possibility that soluble factors secreted by these cells contribute to arterial remodeling. This review discusses the clinical features of VZV vasculopathy and potential mechanisms of VZV-induced cerebrovascular remodeling and stroke.