I have never been told exactly what Plaquenil does for SLE. I just know my Rheumatologist put me on it. I stopped going to him because he was so negative and I lost an entire year with my family and friends because I was scared to death that being outside in the heat or cold would make me worse. My family doctor prescribes my medicine now and I only go to the Rheumatologist if I have a flare. I am doing very well but I want to know more about what Plaquenil actually does for SLE.