Indeed we observed a significant correlation between the daily prednisone dose and the SLEDAI score (r = 0.5; P = 0.0003; Figure 3a), suggesting that increased proportions of CD4+CD25-Foxp3+ T cells in SLE patients treated with a higher glucocorticoid dose can be explained by higher disease activity. Here, FOXP3 is linked to systemic lupus erythematosus.