2.2 Antibody tests
CSF and blood samples were used to test for MOG and NMDAR antibodies. Serum MOG positivity and CSF NMDAR positivity were considered as necessary conditions for diagnosis of the overlapping disease. MOG antibody testing was performed by King Med Center for Clinical Laboratory (Guangzhou, China) using a live cell-based assay (CBA) with cells expressing the full-length human MOG antigen. Endpoint titration was performed as previously describe [16]. AQP4 and MBP antibodies were routinely detected with MOG antibodies to exclude NMOSD and other forms of CNS inflammatory demyelination. The NMDAR antibody was examined using a fixed cell-based assay at the King Med Center for Clinical Laboratory (Guangzhou, China). Additional autoimmune antibodies (AMPA1, AMPA2, LGI1, CASPR2, and GABABR) were tested simultaneously. Five patients were tested for oligoclonal bands to measure intrathecal IgG synthesis.