SLE patients ( n = 57 ) with stable , inactive disease , a serum 25-hydroxyvitamin D ( 25 [ OH ] D ) level 20 ng/ml , an elevated anti-double-stranded DNA antibody level , and an IFN signature ( as determined by measuring the expression levels of 3 IFN response genes ) were randomized into a 12-week double-blind , placebo-controlled trial of vitamin D3 at doses of 2,000 IU or 4,000 IU .