Over half of anti-NMDA receptor encephalitis (NMDARE) is unrelated to etiologies such as teratomas or herpes simplex encephalitis. Bacillus mannanilyticus nonribosomal peptide synthetase (NRPS) shares a protein sequence with GluN1. After confirming the anti-NRPS antibody immunoreactivity in an index patient by liquid chromatography-tandem mass spectrometry (LC-MS/MS), we identified 24/57 (42%) patients with similar immunoreactivity patterns by western blotting. These patients mostly (20/24 [83%]) did not have ovarian teratomas, had fewer medial temporal (2/24 [8%]) and any (5/24 [21%]) brain lesions and less pleocytosis (13/24 [54%]). These results identified an anti-NMDARE subgroup with a distinct immunoreactivity pattern, which needs further investigation.
- Anti-NMDA receptor encephalitis
- Bacillus mannanilyticus
- Nonribosomal peptide synthetase