Safety and clinico-biological efficacy of vitamin D supplementation in SLE patients. Time evolution of serum 25(OH)D levels (A), disease activity assessed by the SLEDAI (B), and anti-dsDNA levels (C). Serum 25(OH)D levels dramatically increased with vitamin D supplementation, while anti-dsDNA levels decreased. The dotted line in panel A indicates normal values. Box plots indicate median, interquartile ranges, minimum and maximum values. Histograms indicate mean ± standard error of the mean (SEM). *P < 0.05, **P < 0.01, ***P < 0.001 versus Day 0; Wilcoxon test.