Impact of blood-brain barrier disruption on newly diagnosed neuromyelitis optica spectrum disorder symptoms and prognosis

Background: Blood-brain barrier (BBB) disruption and ensuing immune activation are central to the pathogenesis of central nervous system (CNS) inflammatory diseases. However, the influence of BBB permeability on the clinical signs and prognosis of newly diagnosed neuromyelitis optica spectrum disorder (NMOSD) has not been examined. We investigate the relationships between BBB permeability as showed by the albumin quotient (qalb) and clinical features of NMOSD. Methods: Demographic and clinical data of 46 patients, including peripheral blood (PB) measures (serum albumin concentration and total leukocyte, neutrophil, total lymphocyte, CD4+ T cell, and CD8+ T cell counts, complement C3 and C4 concentrations, AQP4-IgG titer),autoimmune antibody titers (ANA/SSA/SSB/ Ro-52), and cerebrospinal fluid (CSF) parameters (total leukocyte count, total protein and albumin concentrations, AQP4-IgG titer), were compared between qalb(BBB permeability) increased and normal groups. Complete measures were not obtained from 9 patients, but all other measures were included in the analysis. Results: According to the calculated qalb, 15 patients with albumin quotient (qalb) > (4 + age/15) x 10(-3) were assigned to the qalb increased (high BBB permeability) group (33%) and the remainder to the qalb normal group. Compared to the qalb normal group, the qalb increased group exhibited significantly lower serum albumin (P=0.001) and CD4+ T cell count (P=0.044), CD8+ T cell count (P=0.014), and total T lymphocyte count (P=0.016). The qalb increased group proved higher CSF albumin, total protein, leukocyte count, and IgG titer (all P=0.000). Optic neuritis and optic nerve abnormalities on magnetic resonance images were also more frequent in the qalb increased group (P=0.037 and 0.038, respectively). Patients in the qalb increased group showed significantly poorer treatment response as indicated by the lower post-treatment change in Expanded Disability Status Scale (EDSS) score compared to the qalb normal group. Conclusions: BBB permeability is strongly associated with the clinical features and treatment response of newly diagnosed NMOSD. The qalb is a potentially valuable indicator of disease severity and an index to guide personalized treatment.