Background
Anti– N-methyl-D-aspartate receptor (NMDAR) encephalitis is a severe autoimmune disorder characterized by high intrathecal antibody synthesis. Little is known about the long-term follow-up of the cerebrospinal fluid antibody status.
Objective
To describe persistent intrathecal antibody synthesis in a clinically healthy person 15 years after recovering from anti-NMDAR encephalitis.
Design
Case report.
Setting
Academic medical center.
Patient
A 40-year-old woman who had been diagnosed as having encephalitis of unknown origin in 1995.
Main Outcome Measures
Clinical evaluation and NMDAR antibody testing.
Results
On reexamination in 2011, the patient had fully recovered. Investigation of archived as well as follow-up serum and cerebrospinal fluid samples revealed intrathecal synthesis of NMDAR antibodies.
Conclusions
This is the longest follow-up on a patient with anti-NMDAR encephalitis. Our findings emphasize that intrathecal antibody synthesis does not necessarily reflect disease activity and that the significance of NMDAR antibody titers needs to be interpreted for each patient according to the clinical context.