What is Lupus?

[ABliske]

I don't think there's a good place to post this, but my sister is going through the process of being diagnosed with Lupus. What is it exactly? All I know is that the cells have extra protein. Is that right? It can damage various organs and be treated with steriods.
She's a mom of 8 and really needs to be feeling good!!!! What has helped those of you who have it? I'd really like to be a good support for her.