Bickerstaff brainstem encephalitis with or without anti-GQ1b antibody

OBJECTIVE: To clarify the differences in clinical characteristics between anti-GQ1b antibody-positive and antibody-negative Bickerstaff brainstem encephalitis (BBE). METHODS: We compared 73 anti-GQ1b antibody-positive BBE cases with 10 antibody-negative cases. Their clinical information and sera were collected from various hospitals throughout Japan between 2014 and 2017. The anti-GQ1b antibody was examined in each serum sample by ELISA. RESULTS: We identified the distinctive findings of anti-GQ1b antibody-positive BBE compared with the antibody-negative cases: (1) upper respiratory infection and sensory disturbance were more common, (2) the cell count or protein concentration was lower in the CSF, (3) the abnormal findings on brain MRI were less, and (4) the consciousness disturbance disappeared earlier. Furthermore, IV immunoglobulin (IVIG) was more frequently administered to the anti-GQ1b antibody-positive cases of BBE compared with the antibody-negative cases. CONCLUSIONS: BBE with anti-GQ1b antibody has homogeneous features. IVIG is the treatment used prevalently for BBE with anti-GQ1b antibody in Japan.