TNF and systemic lupus erythematosus: IL-37 significantly reduced the LPS-induced TNF-α, IL-6 and IL-1β mRNA expressions at 100 ng/ml and 200 ng/ml (Additional file 2A-C), but the expression of IL-10 mRNA was not clearly to be inhibited (Additional file 2D).To further address the effect of IL-37 on cytokines in PBMCs from SLE patients, IL-37 (100 ng/ml) was added to the cultures of PBMCs from SLE and healthy controls separately.