Pathogenic Antibodies and (Rapidly Progressive) Dementia syndromes

Dementia syndromes are very common, their origin is often unclear, and there is
no cure. Antibody-mediated encephalitis can mimic dementia syndromes as
cognitive dysfunction can be prominent. Recently, there have been reports and
small patient series with (rapid progressive) dementia and known antibodies,
profiting from immunotherapy. However, late-onset autoimmune encephalitis can
resemble less progressive dementia syndromes, easily missed and remain
untreated. Literature does not provide clues of clinical markers suggestive for
antibody-mediated dementia. The current studies are biased: selection of cases
makes it difficult to relate to the average memory clinic patient; part of the
patients are missed by using less sensitive and specific serum (instead of
CSF), and by testing only for known antibodies. This work has led us to
hypothesize that a small but significant part of patients with dementia
syndromes have pathogenic antibodies that mediate the disease, especially in
those patients with rapidly progressive dementia. Some antibodies are known,
but others are to be identified.

1) Establish a comprehensive clinical and antibody profile of autoimmune
synaptic encephalitis in dementia syndromes.
2) To assess outcome and provide diagnostic guidelines who to test and in whom
testing will be unnecessary, and elucidate biomarkers to predict who to test.
3) Determine the effects of patients* antibodies on synaptic function in vitro
and in vivo with the goal of understanding how autoimmunity affects human
behavior and memory.

observational cohort study

The study patients will have one venapunction with negligible risk and burden.
As the diseases at hand can affect the patients cognition the study cannot be
extrapolated in non-dementia patients.