The Effect of Calcitriol on Progress and Activity of Lupus Nephritis

Inclusion Criteria: * Aged 18-65 years * Baseline Systemic Lupus Erythematosus Disease Activity Index score \<= 4 * Estimated glomerular filtration rate more than 15 ml/min/1.73m2 * Proteinuria \> 1 g/day (or proteinuria \> 1 g/g-Cr) in 2 consecutive samples within 12 weeks despite ACE inhibitor at least 3 months * On maintenance dose of prednisolone \< 15 mg/day with or without other immunosuppressive medications * Serum calcium level in normal range( 8.5-10.5 mg/dl) * History of biopsy-proven lupus nephritis clinical quiescent SLE for at least 3 month * Willingness to give written consent and comply with the study protocol Exclusion Criteria: * Pregnancy, lactating or childbearing potential without effective method of birth control * Severe gastrointestinal disorders that interfere with their ability to receive or absorb oral medication * History of malignancy, including leukemia and lymphoma within the past 2 years; Systemic infection requiring therapy at study entry * Any other severe coexisting disease such as, but not limited to, chronic liver disease, myocardial infarction, cerebrovascular accident, malignant hypertension * History of drug or alcohol abuse within past 2 years * Vitamin D deficiency(25 hydroxy vitamin D less than 20ng/ml) * Participation in any previous trial on vitamin D analogue * Patients receiving treatment of vitamin D and/or its analogue for other medical reasons within the past 4 weeks * Patients who are taking multivitamin supplement that contains vitamin D could be enrolled after 4 weeks of wash out period by changing to a preparation that has no vitamin D * On other investigational drugs within last 30 days * History of a psychological illness or condition such as to interfere with the patient's ability to understand the requirement of the study * History of non-compliance; Known history of sensitivity or allergy to vitamin D analogs