Patients between 15 and 40 years of age with severe SLE affecting a major organ that is resistant to standard treatment may be eligible for this study. Candidates are screened with a medical history and physical examination, blood and urine tests, skin tuberculin test, and radiology studies to evaluate the extent of disease. They have endocrinology, nutrition, dental, and social work consultations, ultrasound or MUGA (multi-gated acquisition scan) scan heart imaging, electrocardiogram and lung function tests, bone marrow biopsy, and lymph node aspirate. Depending on which organs are affected, patients may have additional tests, such as lumbar puncture (spinal tap), kidney or lung biopsy, MRI (magnetic resonance imaging) of the brain and spinal cord, and PET (positron emission tomography) scan. They also complete quality of life questionnaires and have disability functional testing and neurocognitive (thinking) assessments.