Pediatric Opsoclonus Myoclonus Ataxia Syndrome (OMAS) is a rare but devastating autoimmune disorder characterized by acute onset of opsoclonus, myoclonic jerking and ataxia, and disordered mood/behavior in a previously well child. At least 50% of children with OMAS have a detectable neuroblastoma (NB) at the time of diagnosis. However, only 2-3% of children with NB develop OMAS, raising the question of what triggers autoimmune disease in this subset of patients. It is also striking that tumor-related survival rates are significantly higher among children with OMS than among NB patients at large.
Though this condition was first described over 50 years ago, no specific molecular marker of this disease is known, and the identity of the antigen responsible for autoimmune attack remains unknown. The current standard of care for treating OMAS involves relatively non-specific immunosuppressive therapies, with variable success: although frank ataxia and opsoclonus typically resolve with treatment, most children with OMAS suffer from lasting neurocognitive and/or motor deficits. Identification of the specific antigen(s) underlying OMAS pathology, or other molecular markers of disease, would represent critical advances en route to its effective diagnosis and treatment. Further, if the immune component of OMAS is related to improved NB survival in OMAS patients, then understanding the basis of this tumor immunity could have clinical relevance for NB in a broader context.
We are using RNAseq and immune sequencing of TILs in OMAS-associated NBs, and non-OMAS NBs of both low-risk and high-risk subtypes, to better understand how OMAS associated NB is different. Our results will be presented.