Humoral and cellular immune responses in neuromyelitis optica

Abstract

Neuromyelitis optica (NMO) is an inflammatory and demyelinating syndrome characterized by severe attacks of myelitis and optic neuritis. A crucial role for humoral immunity in the NMO pathogenesis has been suggested by the detection of a highly specific serum autoantibody NMO immunoglobulin G that binds to aquaporin4 (AQP4) water channels, and the pronounced deposition of immunoglobulins colocalizing with products of complement activation in a vasculocentric pattern around thickened hyalinized blood vessels in NMO lesions. Moreover, we have recently demonstrated that levels of several cytokines such as interleukin (IL)-6 and IL-1β are increased in the cerebrospinal fluid of NMO patients, and the peripheral white matter-demyelinating cord lesions of NMO were accompanied by infiltration of lymphocytes in the leptomeningeal membrane. These cellular elements in patients with NMO might aid B cells and plasma cells in AQP4 antibody production, and break the blood-brain barrier due to the access of AQP4 antibodies to the extracellular domain of AQP4 at the astrocytic foot process.