Prevalence of N-methyl-D-aspartate receptor autoantibodies in the peripheral blood: healthy control samples revisited.

Prevalence ofN-Methyl-D-Aspartate Receptor Autoantibodies in the Peripheral Blood: Healthy Control Samples Revisited In March 2013, we published a study in JAMA Psychiatry assessing the prevalence of anti–N-methyl-D-aspartate glutamate receptor (NMDAR) serum autoantibodies in unmedicatedacutely ill patientswith schizophrenia,majordepression (MD), borderlinepersonality disorder (BLPD), and healthy control individuals without neuropsychiatric disorder.1 The laboratory analyses of this set of samples were done in 2010. N-methyl-Daspartate glutamate receptor antibodies were identified in 15 patients, primarily in thosewith a clinical diagnosis of schizophrenia (12 of 121, 9.9%) as opposed to thosewithMD (2 of 70, 2.9%), those with BLPD (0 of 38, 0%), and control individuals (1 of 230, 0.4%). Two patients were initially misdiagnosed as having catatonic or disorganized schizophrenia. Retrospectively, these caseswere reclassified as caseswith NMDAR encephalitis (presence of specific IgG anti-NR1a autoantibodies in both serum and cerebrospinal fluid).