Expanding clinical spectrum from Hashimoto's encephalopathy to anti‐NAE antibody‐associated disorders (NAEAD)

Abstract

Using proteomic analysis, we identified anti‐NAE antibodies (autoantibodies against NH2‐terminal of alpha‐enolase) as a diagnostic marker for Hashimoto's encephalopathy (HE). As cases of HE with serum anti‐NAE antibodies accumulated, the clinical spectrum of HE with anti‐NAE antibodies became expanded. In addition, it is now known that antibodies can be detected in other diseases that differ from conventional HE. We recently reported the detection of anti‐NAE antibodies in patients with a clinical diagnosis of multiple system atrophy or corticobasal syndrome. These findings suggest that anti‐NAE antibodies indicate an immune mechanism in the pathogenesis of neurodegenerative diseases. We propose a novel disease concept for anti‐NAE antibody‐associated disorders (NAEAD). The clinical spectrum of NAEAD is not limited to HE but is a broad spectrum that partially shares several autoimmune neurological diseases, including autoimmune acute encephalopathy, autoimmune cerebellar ataxia, and autoimmune psychosis, and even extends to immune‐associated neurodegenerative diseases.