I just found this thread. Sorry to hear about your grand daughter but if it helps any my grandmother was diagnosed with Lupus as a child, she lived a relatively normal life and DID NOT die from it, she was in her 70's when she died. She didn't have a special diet or anything like that, just did and ate what she wanted to. But as you know now we all know certain foods can cause reactions that they never used to associate together.
Best of luck for your whole family.
