Immune cell profiling in the cerebrospinal fluid of patients with primary angiitis of the central nervous system reflects the heterogeneity of the disease.

Primary angiitis of the central nervous system (PACNS) is a rare and heterogeneous inflammatory disease of the CNS vasculature with poorly understood pathophysiology. Comprehensive immune-cell phenotyping revealed increased frequencies of leukocytes in the cerebrospinal fluid (CSF) of PACNS patients compared to patients with multiple sclerosis, ischemic stroke, and somatoform disorders (n = 18 per group). Changes in the intrathecal immune-cell profile were heterogeneous in PACNS. While proportions of T-cell subsets remained unaltered, some PACNS patients showed a shift toward NK- or B cells. Intrathecal immunoglobulin synthesis was observed in a subgroup of PACNS patients with an increased frequency of antibody producing plasma cells.