Exploratory investigation on antibodies to GluN1 and cognitive dysfunction in patients with chronic autoimmune psychosis

INTRODUCTION

Mild cognitive dysfunction has been implicated in a number of psychiatric diseases and affects social functioning. Although clinical criteria were recently proposed for autoimmune psychosis (AP), biomarkers have not yet been established for the severity and prognosis of cognitive dysfunction. We herein investigated the relationships between 3 types of serum antibodies and cognitive dysfunction in chronic psychiatric patients suspected of AP.

METHODS

We included 31 patients suspected of AP and obtained information on their clinical characteristics. Three types of autoantibodies (the anti-N-methyl-_D-aspartate receptor (anti-NMDAR Ab), anti-N-terminal of GluN1 (anti-GluN1-NT Ab), and anti-thyroid antibodies) were evaluated in serum. Cognitive function was assessed using Wechsler Adult Intelligence Scale-III. We examined the relationships between serum autoantibodies and cognitive dysfunction in patients using multiple regression models.

RESULTS

Serum titers of anti-GluN1-NT Ab significantly contributed to the estimated score of working memory (B= -55.85, β= -0.46, p= 0.01), while no correlation was observed between the other 2 types of antibodies and cognitive function.

CONCLUSIONS

The present results indicate the potential of serum anti-GluN1-NT Ab as a biomarker for the severity and prognosis of cognitive dysfunction underlying various psychiatric symptoms in patients with AP. The pathological significance of anti-GluN1-NT Ab needs to be verified in future studies.

[Clinical featuers of adult patients with post-viral-encephalitis autoimmune encephalitis]

Objective: To explore the clinical features of post-viral-encephalitis autoimmune encephalitis (PVEAE). Methods: Ten cases of PVEAE, who were hospitalized in the Neurology Department of Peking Union Medical College Hospital (PUMCH) between November 2014 and October 2019, were retrospectively reviewed. Clinical manifestation, immunology, neuroradiology, treatment and outcomes were analyzed. Results: There were 5 males and 5 females, with a median age of 44 (18, 66) years. Of 9 cases, the median interval between the two onsets of encephalitis was 37 (24, 60) days, and there was no obvious interval in case 7. In viral encephalitis phase, the peak modified Rankin scale (mRS) was 4.5 (4.0, 5.0) and the remission mRS was 2.0 (1.0, 3.0). In autoimmune encephalitis (AE) phase, the peak mRS was 4.0 (3.0, 5.0). Symptoms of AE included mental and behavioral abnormalities (10/10), amnesia (10/10), motor disorders (5/10), autonomic dysfunction (5/10), speech disorders (4/10), seizures (2/10) and consciousness disturbance (2/10). On average, each case presented with 4 (2, 6) symptoms. In AE phase, the positive rate of anti-N-methyl-D-aspartate (anti-NMDA) receptor antibody in cerebrospinal fluid (CSF) was 80% (8/10), while in serum it was only 20% (2/10). Neuroimaging showed that in AE phase, the lesions expanded in 8 cases, remained unchanged in 1 case and shrank in 1 case. In AE phase, 10 cases received first line treatments, and 2 cases accepted long-course immunotherapy. After treatment, symptoms of 9 cases were obviously relieved. The mRS for short-term and long-term outcomes was 2.0 (1.0, 4.0) and 1.0 (0, 2.0), respectively. Conclusions: PVEAE might present with either typical biphasic course or monophasic/pseudo-monophasic course. In AE phase, anti-NMDA receptor antibody turned positive in most cases. Much importance should be attached to the recognition and diagnosis of PVEAE and treat it actively thereafter.

Prevalence of elevated serum anti-N-methyl-D-aspartate receptor antibody titers in patients presenting exclusively with psychiatric symptoms: a comparative follow-up study

BACKGROUND

Increasing numbers of patients with elevated anti-N-methyl-D-aspartate (NMDA) receptor antibody titers presenting exclusively with psychiatric symptoms have been reported. The aim of the present study was to clarify the prevalence of elevated serum anti-NMDA receptor antibody titers in patients with new-onset or acute exacerbations of psychiatric symptoms. In addition, the present study aimed to investigate the association between elevated anti-NMDA receptor titers and psychiatric symptoms.

METHODS

The present collaborative study included 59 inpatients (23 male, 36 female) presenting with new-onset or exacerbations of schizophrenia-like symptoms at involved institutions from June 2012 to March 2014. Patient information was collected using questionnaires. Anti-NMDA receptor antibody titers were measured using NMDAR NR1 and NR2B co-transfected human embryonic kidney (HEK) 293 cells as an antigen (cell-based assay). Statistical analyses were performed for each questionnaire item.

RESULTS

The mean age of participants was 42.0 ± 13.7 years. Six cases had elevated serum anti-NMDA antibody titers (10.2 %), four cases were first onset, and two cases with disease duration >10 years presented with third and fifth recurrences. No statistically significant difference in vital signs or major symptoms was observed between antibody-positive and antibody-negative groups. However, a trend toward an increased frequency of schizophrenia-like symptoms was observed in the antibody-positive group.

CONCLUSION

Serum anti-NMDA receptor antibody titers may be associated with psychiatric conditions. However, an association with specific psychiatric symptoms was not observed in the present study. Further studies are required to validate the utility of serum anti-NMDA receptor antibody titer measurements at the time of symptom onset.