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.