Abstract
We investigated the prevalence of AQP4 IgG in classical multiple sclerosis (MS), Neuromyelitis optica (NMO) and MS with longitudinally extensive spinal cord lesions (LESCL) from a Western Australian MS cohort. There were only two cases (2%) found to be seropositive in a total of 96 samples. One positive case was found among 52 MS patients (1.9%), the other among the 18 LESCL or NMO patients (5.6%). Twenty three PPMS were all seronegative. There were 14 LESCL cases in this MS cohort with one AQP4 IgG positive (7.1%). In our WA MS cohort there were three NMO patients previously NMO-IgG negative (Mayo Clinic), one also AQP4 IgG negative. The other two cases were deceased. Our study showed a very low rate of anti-AQP4 antibody in Caucasian MS patients. Although one positive case was associated with LESCL, the sensitivity of AQP4 IgG was still extremely low in comparison with other studies using the same test. These results emphasise the need for further study on the clinical utility of AQP4 serology1. We are preparing a comprehensive serological and immunogenetic examination of 900 patients.