·This was a cross-sectional study. From January 2018 to December 2018, 40 patients who underwent kidney biopsy and was diagnosed as having LN and 68 healthy controls in Renji Hospital, Shanghai Jiao Tong University School of Medicine were included. Clinical characteristics and laboratory parameters were collected and serum sIL-2R and TNF-α were measured. Serum sIL-2R and TNF-α were compared between the LN group and the control group. The correlations of sIL-2R and TNF-α with laboratory parameters of LN were evaluated by Spearman analysis. Further, the LN patients were divided into the active group and the non-active group. The predictive values of sIL-2R and TNF-α were evaluated by Logistic analysis and receiver operating characteristic (ROC) curve.

·Serum sIL-2R and TNF-α levels were significantly higher in the LN group than those in the control group (all P<0.05). Positive correlations were observed between sIL-2R and systemic lupus erythematosus disease activity index-2000 (SLEDAI-2K), 24 hours urine total protein (24h-UTP), anti-double stranded DNA antibody (anti-dsDNA), serum creatinine and high sensitive C-reactive protein (h-CRP) (all P<0.05), while a negative correlation was found between sIL-2R and C3 (P=0.002). Meanwhile, TNF-α positively correlated with SLEDAI-2K, 24h-UTP, serum creatinine and h-CRP, whereas no significant correlation was found between TNF-α and anti-dsDNA or C3. 24h-UTP, anti-dsDNA, serum creatinine, sIL-2R and TNF-α were significantly higher (all P<0.05) and C3 was lower in the active group than those in the non-active group of LN (P=0.000). Anti-dsDNA (OR=1.025) and sIL-2R (OR=1.011) were predictive factors of disease activity of LN (all P<0.05) and the area under ROC curve of their combination of prediction was 0.957 (P=0.000).

·Serum sIL-2R and TNF-α levels increase in LN patients and are correlated with the disease activity of LN. Combining anti-dsDNA and sIL-2R can predict the disease activity of LN effectively.