IFNA1 and systemic lupus erythematosus: 54 SLE patients with vitamin D insufficiency [25(OH)D ≤ 20 ng/mL], high anti-dsDNA antibodies, stable, inactive illness, and an established IFN signature were randomly assigned to receive either a placebo (n = 19), vitamin D3 2000 IU/day (n = 17), or vitamin D3 4000 IU/day (n = 18) for a duration of 12 weeks.