CD4+ T Cells Predominate in Cerebrospinal Fluid and Leptomeningeal and Parenchymal Infiltrates in Cerebral Amyloid β-Related Angiitis

Background: In amyloid beta (A beta)-related angiitis (ABRA) of the central nervous system (CNS), cerebral amyloid angiopathy occurs in association with primary vasculitis of small- and medium-sized leptomeningeal and cortical arteries. It has been suggested that ABRA is triggered by vascular deposition of A beta followed by an A beta-directed (auto) immune response. Objective: To provide a detailed description of the cellular composition of the inflammatory infiltrates in the cerebrospinal fluid (CSF) and CNS and their response to immunotherapy in a typical case of ABRA. Design: Report of a single case. Setting: Neurologic referral center. Patient: 67-year-old white woman. Main Outcome Measures: Neurologic examination, magnetic resonance imaging, lumbar puncture, flow cytometry, leptomeningeal biopsy, and histopathologic analysis. Results: In a typical case of ABRA, we demonstrate for the first time the presence of a vast majority of partially activated CD4(+) T cells in CSF and leptomeningeal and parenchymal (peri) vascular infiltrates, which were frequently found in close proximity to major histocompatibility complex (MHC) class II-expressing microglia, epithelioid macrophages, and multinucleated giant cells containing intracellular deposits of A beta. Conclusion: Our findings support the notion of adaptive A beta-directed autoimmunity as the underlying pathogenic mechanism in ABRA. Arch Neurol. 2012; 69(6): 773-777. Published online February 20, 2012. doi:10.1001/archneurol.2011.2441