【Abstract】ObjectiveTo explore the expression of Interleukin-37 (IL-37) in patients with type 2 diabetes mellitus complicated with diabetic kidney disease (DKD) and investigate correlation between IL-37and DKD. MethodsA total of 228 patients with T2DM were included in this pilot study. According to urinary albumin to creatinine ratio(UACR) and estimated glomerular filtration rate (eGFR)，the patients were separated into three groups：normoalbuminuria (DM) group with 80 patients，microalbuminuria (early DKD) group with 76 patients and macroalbuminuria (clinical DKD) group with 72 patients.60 healthy people were selected as control group. The basic data，laboratory examination data of patients in each group were collected. Level of IL-37 in each group were detected by Enzymelinked immunosorbent assay (ELISA)，Levels of IL-37 between the study groups were examined and compared. The correlations between IL-37 concentration and laboratory examination data were analyzed. ResultsIL-37 concentration in DM group，early DKD and clinical DKD group were significantly higher than control group (P<0.05)，and the clinical DKD group was significantly higher than the early DKD group (P=0.043). However，the concentration of IL-37 in the early DKD group was not significantly different from that of the DM group (P>0.05). Spearman correlation analysis showed that positive correlations were detected between IL-37 and 24-hours urinary protein，urinary ALB，urine α1-MG，β2-MG and HbA1C (r=0302，0.286，0.222，0.216，0.265，respectively，P<0.05)； However，a negative correlation between IL-37 and eGFR (r=-0.357，P=0.001). Logistic regression analysis suggested that IL-37 may be a protective factor for T2DM complicated with DKD (OR=0.822，95%CI：0.7020.962）. ConclusionThe serum concentration of IL-37 is associated with the development of DKD in T2DM patients. IL-37 might be a potential new method for the treatment of DKD.