The first signs of this disease (NMDAR-antibody encephalitis) often show up as disturbances in mental state before progressing to seizures, movement disorder, and coma.
The new study, Cervical lymph nodes and ovarian teratomas as germinal centres in NMDA receptor - antibody encephalitis, is published in Brain. It pioneers the direct sampling of neck lymph nodes to study immune reactions and response. More broadly, this safe and reliable technique, which was carried out as part of a collaboration with the John Radcliffe Radiology Department, could be used to study interactions between the brain and the immune system.
The study also consolidates the role of ovarian teratoma in breaking immune tolerance and the urgency needed to identify and treat any ovarian teratomas, which are present in about a third of patients with NMDAR-antibody encephalitis, despite it being a rare tumour.
Dr Adam Al-Diwani, NIHR Clinical Lecturer, study lead, Department of Psychiatry, University of Oxford, said:
'We investigated how autoimmunity comes about by studying patient samples of blood, teratoma samples and direct sampling of neck lymph nodes. We found that a process usually important in fighting infection - germinal centre reaction, in which B cells become educated to make a specific immune response - is happening within the tumour. We found that this is also happening in neck lymph nodes, particularly in patients whose illness was harder to treat, but not in those who had responded to treatment, including tumour treatment.
'The impact for clinical practice is an emphasis on treating the cellular basis of this disease in addition to targeting antibodies alone. Studying neck lymph nodes may shed light on more common neuropsychiatric conditions including dementia and brain injury.'
This research was supported by the NIHR Oxford Health and Oxford Biomedical Research Centres, as well as Wellcome, the Medical Research Council, and the British Medical Association Foundation.
Watch more about the research - Cervical lymph nodes & ovarian teratomas as germinal centres in NMDA receptor-antibody encephalitis.