Glutamate receptor delta2 serum antibodies in paediatric opsoclonus myoclonus ataxia syndrome

Objective: To identify neuronal surface antibodies in opsoclonus myoclonus ataxia syndrome (OMAS) usingcontemporary antigen discovery methodology. Methods: OMAS patient serum IgG immunohistochemistry using age-equivalent rat cerebellar tissue was followed by immunoprecipitation, gel electrophoresis and mass spectrometry. Data are available via ProteomeXchange (identifier PXD009578). This generated a list of potential neuronal surface cerebellar autoantigens. Live cell-based assays (CBA) were used to confirm membrane-surface antigens and adsorb antigen-specific IgGs. The serological results were compared to the clinical data. Results: Four of the six OMAS sera tested bound rat cerebellar sections. Two of these sera with similar immunoreactivities were used in immunoprecipitation experiments using cerebellum from postnatal rat pups (P18). Mass spectrometry identified 12 cell-surface proteins, of which glutamate receptor delta 2 (GluD2), a predominately cerebellar-expressed protein, was ...