Anti-NMDAR antibodies in new-onset psychosis. Positive results in an HIV-infected patient.

The role of neuronal surface autoantibodies (NSAs) in non-encephalitic psychosis is of recent and controversial interest. Most of the studies relating NSAs with psychosis are retrospective and only focused on the N-methyl-d-aspartate glutamate receptor (NMDAR). Our goal was to evaluate the prevalence of IgG antibodies against the NMDAR NR1 subunit (NMDAR-Abs) along with five additional NSAs in 61 first psychotic episode patients and 47 matched controls. We found two patients positive for NMDAR-Abs (3.3%). One of them was eventually considered to have been misdiagnosed and reclassified as encephalitis. The other met the criteria for bipolar I disorder, presented no neurological symptoms and had a comorbid HIV infection of vertical transmission. This is the first reported case of an HIV-infected patient with psychosis associated with NSAs. This study shows that patients presenting with clinically incomplete forms of anti-NMDAR encephalitis, with predominant or isolated psychiatric symptoms, can remain undetected if no ancillary tests are performed. To improve patient diagnosis and treatment of individuals with a first psychotic episode, more detailed neurological examinations might be needed. Further studies are required to better clarify the role of NSAs in the neuropsychiatric effects of HIV infection.

Neuronal surface antibodies in HIV-infected patients with isolated psychosis.

Neuronal surface antibodies (NSA) involved in autoimmune encephalitis (AE) have been related to relapses in HVS encephalitis. Their role in non-encephalitic psychosis is controversial. We previously reported an HIV-infected patient, NSA-positive, only presenting psychosis. Therefore, we determined the NSA prevalence in a prospective cohort of 22 HIV-positive patients with psychosis and we analyzed the frequency of HIV infection among NSA tested patients due to AE suspicion. We found no NSA in the prospective cohort. In the retrospective analysis, 22% of NSA-positive versus 4.6% of negative patients were HIV-positive. Wider studies are required to clarify the relationship between NSA and HIV infection.