Fig. 1

CircIBTK expression was downregulated in systemic lupus erythematosus (SLE) and correlated with clinicopathological variables in patients with SLE. a, b Expression of circIBTK and IBTK mRNA in periperhal blood mononuclear cells (PBMCs) from 42 patients with SLE and 35 healthy controls (HC) compared using the unpaired Student’s t test. c Correlation between expression of circIBTK and IBTK mRNA levels analyzed with Spearman’s analysis. d-f Correlation between expression of circIBTK and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score, anti-dsDNA titer or complement C3 level analyzed with Spearman’s analysis. g, h SLEDAI score and circIBTK expression in eight patients who achieved significant clinical improvement after systematic treatment; data were compared using the paired Student’s t test. The SLEDAI score in two patients declined from 11 to 3 and so there are two lines that overlap in g. i ROC curve of relative circIBTK expression for differentiating 42 patients with SLE from 35 HC. Results are represented as mean ± SD. **P < 0.01, ***P < 0.001