It includes additional immunotherapy cross-sectional groups; analysis of the relation to OMS severity (video documented and scored) and duration; comparison with APRIL, inflammatory chemokines, oligoclonal bands, and lymphocyte subsets; longitudinal studies of BAFF and APRIL, and comparative studies in other inflammatory neurological disorders (OIND). This evidence concerns the gene TNFSF13B and opsoclonus-myoclonus syndrome.