The purpose of this study is to test the safety and effectiveness of different doses of vitamin D in patients with Systemic Lupus Erythematosus (SLE). A long term goal is to determine if vitamin D could be used as a treatment and/or preventative of SLE.

Inclusion Criteria:

• SLE by ACR criteria (revised 1997)
• African American, participating in the SLE in Gullah Health (SLEIGH) Study
• Outpatient
• Stable disease with no BILAG A or B in any system for the past 4 weeks
• Stable prednisone (or equivalent corticosteroid) dose ≤ 20 mg/day for ≥ 4 weeks prior to study entry
• Baseline 25(OH)D concentration of < 30 ng/ml
• Willingness to discontinue other vitamin D supplements and/or multivitamins containing vitamin D while participating in the study
• Age 18 - 85 years
• Ability to complete questionnaires in English
• Ability to give informed consent

Exclusion Criteria:

• Presence of hypercalcemia (>10.4 mg/dL), hypercalcuria (urinary calcium/creatinine ratio ≥ 0.8 mmol/mmol) or known primary hyperparathyroidism
• Liver disease (serum ALT, AST >2x normal) or total serum bilirubin >1.5x normal
• History of renal stones
• Current treatment with any dose of cyclophosphamide
• Dialysis or creatinine > 2.5 mg/dL
• Pregnancy
• Current drug or alcohol abuse
• Anticipated poor compliance