Factors influencing the cerebrospinal fluid antibodies to aquaporin-4: a study of 87 patients with neuromyelitis optica spectrum disorder

Abstract

Abstract Background: Serum AQP4 antibody (AQP4-IgG) is the causative antibody of neuromyelitis optica spectrum disorder (NMOSD). AQP4-IgG in cerebrospinal fluid (CSF) of NMOSD patients were seldom studied. In this study, we measured antibody titers in time-matched paired CSF and serum samples and explored the relation between CSF AQP4-IgG and patient’s clinical features. Methods: A total of 137 NMOSD patients admitted in the department of Neurology of Renji Hospital from January 2016 to July 2022 were retrospectively reviewed. 87 patients with complete results of paired serum and CSF AQP4-IgG assay were included. Their demographic, clinical, laboratory data and MRI images were collected and analyzed. Result: In this study, 77 patients were seropositive for AQP4-IgG and 10 patients were seronegative. Among the 77 patients seropositive for AQP4-IgG, 47 were CSF-positive and 30 were CSF-negative, while no patients were CSF-positive in the 10 seronegative patients. Between the CSF-positive and CSF-negative groups, there were significant difference in expanded disability status scale (EDSS) scores, relapse proportion, CSF IgG, and CSF IgM, and these indicators were higher in CSF-positive group. We also found a positive correlation between the serum and CSF titer (rs: 0.629, p<0.001). Further logistic multi-factor regression analysis of CSF AQP4-IgG titer revealed that only serum AQP4-IgG titer was ultimately included in the regression model (OR 1.004, 95% CI: 1.001-1.007, p<0.01). Conclusion: AQP4-IgG titer in CSF is mainly affected by serum AQP4-IgG titer. Higher EDSS and a higher presence of relapse status are more common in patients with positive CSF AQP4-IgG.