An immunoassay that distinguishes realneuromyelitis optica signals from a labelingdetected in patients receiving natalizumab

Abstract

This study aimed to develop a sensitive quantitative method for detecting anti-aquaporin 4 (AQP4) antibodies to improve neuromyelitis optica (NMO) diagnosis and distinguish false positives caused by natalizumab treatment. Using sera from 167 individuals, including NMO patients and various controls, an immunofluorescence assay on HEK cells transfected with the M23 isoform of human AQP4 was performed. Results showed that NMO patients' sera were 100% positive for anti-AQP4 antibodies, while other sera were negative. The assay significantly increased signal specificity and reduced false diagnoses, especially in natalizumab-treated patients, with frozen pretreated cells allowing faster detection.