If some forms of lupus can be brought on by medications, then to me, it stands to reason that environmental polutants could also be a calprit.
If you look at the genetic angle of lupus. My mother had it, her mother probably had it, my sister has it and now I'm showing signs and symptoms. We all have grown up in the same environment, so who's to say it's not something we've been exposed to. But then again you would think that the males in my family would show signs of it too.
But that's an interesting question.