A difficult question regarding Lupus (SLE type) can a Dr. or other knowledable person tell help me?

Okay, I was dx'd with lupus 23 yrs. ago. My kidneys failed requiring dialysis and a transplant about 13 years ago after a serious flare and a long hospital stay for treatment a Nocardia infection which left me with abscesses in my lungs and brain. The Nocardia was thought to be brought on by treatment for a serious flare in progress which was being treated with a once a month with IV therapy and tablets I took at home. I cannot remember the name of the med. but it was a drug used to treat some types of cancer. Yes, I was very ill, had seizures and required to have a ventilator and tracheotomy to breathe and was on TPN for a month and a half or better. My kidneys failed at that time. After I was well enough I had a transplant and subsequently put on immunosupressives to maintain the graft. I have had no flares since my extended hospital stay for the Nocardia. My nephrologist told me that many times Lupus kind of fizzles out after it destroys a major organ. Why they do not know, one theory is that the immunsuppressive therapy play a part which makes sense. If this is true then why do they not use these medications to treat a flare? Is this due to the potential complications ociated with the immuosuppression therapy or another reason? Or is it something ociated with losing my kidneys that burns the Lupus out? During the time in dialysis I also had no flares and was actually weaned completely off prednisone I might add.