In amyloid β (Aβ)–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 Aβ followed by an Aβ-directed (auto)immune response.
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.
Report of a single case.
Neurologic referral center.
67-year-old white woman.
Main Outcome Measures
Neurologic examination, magnetic resonance imaging, lumbar puncture, flow cytometry, leptomeningeal biopsy, and histopathologic analysis.
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 Aβ.
Our findings support the notion of adaptive Aß-directed autoimmunity as the underlying pathogenic mechanism in ABRA.