Autoantibodies to neural antigens in CNS demyelinating disorders

The relationship between central nervous system demyelinating disorders (CNSDDs) and anti-neural antibodies (Abs), with the exception of anti-aquaporin 4 (AQP4) Abs, is not well understood. We previously screened for a variety of anti-neural Abs in the sera of Japanese patients with CNSDDs and found three patients with anti-N-methyl-d-aspartate receptor (NMDAR) Abs and three patients with anti-contactin-associated protein 2 (CASPR2) Abs. These Abs have not yet been considered as causing CNSDDs. Here, we describe CNSDD patients with these autoantibodies and discuss whether these Abs are pathogenic or not, based on the clinical presentation and literature documentation. Moreover, we propose points to which attention should be paid when dealing with patients with CNSDDs in a clinical setting.