Here's the thing: that's actually how Lupus is diagnosed, at least in my limited single-data-point experience - my father.
He had a random fluid build-up in his pericardial sac around his heart that was basically squeezing his heart to the point it couldn't function any more. After two weeks in the hospital of diagnostics and so on where the eliminated all kinds of other causes, they defaulted to Lupus and started putting him on steroids, and he's been healthy ever since with absolutely no recurrence.
It will be interesting to see if the causal link between Lupus and Epstein-Barr holds up to further scrutiny - it would be great if we could eliminate the occurrence of autoimmune disease through future vaccination.
Of course we'll need the political loonies to GTFO of the Department of Health and Human Services in order to allow approval of any new vaccines...