The lowdown on what it's all about is something like the following. Obviously I have to confess that the following blurb was nicked from another site that knows a bit more about the technical side than I do ("National Center for Advancing Translational Sciences")

So here you go....

Autoimmune encephalitis refers to a group of conditions that occur when the body's immune system mistakenly attacks healthy brain cells, leading to inflammation of the brain. People with autoimmune encephalitis may have various neurologic and/or psychiatric symptoms. 

And that is that.