Two percent of children with Neuroblastoma, a pediatric solid tumor of the peripheral nerve ganglia, develop Opsoclonus Myoclonus Ataxia Syndrome (OMAS), a paraneoplastic disease characterized by devastating cerebellar and brainstem-directed autoimmunity, but typically with outstanding cancer-related outcomes. Here, we compared tumor transcriptomes and tumor infiltrating T- and B-cell repertoires from a cohort of OMAS subjects with neuroblastoma to a set of controls from 13 low- and 13 high-risk non-OMAS associated neuroblastoma tumors. Overall design: Here, we compared tumor transcriptomes and tumor infiltrating T- and B-cell repertoires from a cohort of OMAS subjects with neuroblastoma to a set of controls from 13 low- and 13 high-risk non-OMAS associated neuroblastoma tumors.