Pranzatelli MR, et al. - An inquiry was set up with regard to the effect of immunotherapy on multiple markers of inflammation in opsoclonus-myoclonus syndrome (OMS), with the intention of identifying which agents were disease modifying. A moderate reduction in cerebrospinal fluid (CSF) B cell expansion served as the primary effect of cyclophosphamide combination therapy on neuroinflammation in OMS. Despite being exploratory, it could offer a steroid sparer option in partially-responsive OMS.