IL-37 inhibits the expression of inflammatory cytokines in PBMCs of patients with SLE. PBMCs from SLE patients (n = 66) and healthy controls (n = 41) were stimulated with IL-37 (100 ng/ml) for 6 hour, the total RNAs were extracted and analyzed for TNF-α (A), IL-1β (C) and IL-6 (E) IL-10 (G) mRNAs by RT-PCR. Box plots show the median values, 25th and 75th quartile and the range of values. The cells were stimulated with IL-37 (100 ng/ml) for 24 hour, and then incubated further with LPS (1 μg/ml) for 6 h, supernatants were examined for TNF-α (B), IL-1β (D), IL-6 (F) and IL-10 (H) levels using enzyme-linked immunosorbent assay (ELISA). Each symbol represents an individual patient or healthy control. Horizontal lines indicate median values. Actual P values are shown in the graph. NS, no significant.