Investigation of anti-NMDA receptor antibodies in first episode psychosis patients

INTRODUCTION: Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune limbic encephalitis, where psychiatric symptoms are often the initial presentation dominant initially. These patients are mainly admitted to psychiatric wards, due to first episode psychosis (FEP). OBJECTIVES: Multiple studies analysed whether anti-NMDAR antibodies were present in the sera of schizophrenic patients, but results have not verified this hypothesis. It is possible, however, that unknown autoimmune antibodies play a role in FEP, similarly to anti-NMDAR antibodies. METHODS: 40 patients with FEP and 30 healthy controls have been recruited to the study. Patients with affective psychosis, drug-related psychosis and patients with diagnosed encephalitis were excluded. The sera were tested with immune fluorescent assays for anti-NMDAR antibodies. A non-specific method was used to test anti-brain antibody activity on monkey-cerebellum and rat-hippocampus slices. RESULTS: Neither the samples from the 40 patients, nor the samples of healthy controls contained anti-NMDAR antibodies. 14 of the patients’ and only 6 of the healthy controls’ serum showed positive reaction of the neuroendothelium. These results suggest that there is a difference between the groups, although the results are not significant. CONCLUSIONS: None of the 40 patients proved positive for anti-NMDAR antibodies in agreement with previous studies. However, a higher proportion of samples from the FEP group showed activity in the neuroendothelium of non-specific immune fluorescent assays compared to healthy controls. Based on literature and on our experience, it is possible, that unknown autoimmune antibodies play role in FEP. DISCLOSURE: No significant relationships.