ObjectiveTo investigate the clinical value of the combined detection of urinary exosome dipeptidyl peptidase 4(DPP-4), α1-microglobulin(α1-MG), cystatin C(Cys C) and transferring(TRU) in patients with diabetic nephropathy.

MethodsThe levels of DPP-4, α1-MG, Cys C, TRU, IgG, microalbuminuria in 120 diabetic patientsincluding normal proteinuria group(40 cases), microalbuminuria group(40 cases) and massive proteinuria group(40 cases) and healthy control group(40 cases) were detected.The Pearson correlation analysis was used to evaluate the correlation among the items.The receiver operating characteristic curve was used to evaluate the value of DPP-4, Cys C, α1-MG, TRU and IgG in the diagnosis of diabetic nephropathy.

ResultsThe contents of DPP-4 and α1-MG in urine exosomes of diabetic nephropathy patients were higher than those in control group(P < 0.05), and increased with the increasig of urine protein content(P < 0.05 to P < 0.01).The differences of the levels of Cys C, TRU and IgG between normal albuminuria group and control group were not statistically significant(P>0.05), and the levels of Cys C, TRU and IgG in microalbuminuria group and massive albuminuria group were higher than those in control group(P < 0.05 to P < 0.01).The urinary exosome DPP-4 was positively correlated with α1-MG, Cys C, TRU and IgG(P < 0.05).The areas under the receiver operating characteristic curve of DPP-4, α1-MG, Cys C, TRU, IgG, and combined DPP-4, α1-MG, Cys C and TRU were 0.742, 0.736, 0.843, 0.868, 0.836 and 0.899, respectively.The sensitivity, specificity, positive predictive value and negative predictive value of the combined detection of DPP-4, α1-MG, Cys C and TRU were 93.42%, 86.90%, 86.59% and 93.59%, respectively.

ConclusionsThe combined detection of urinary exosome DPP-4, urinary Cys C and urinary α1-MG and TRU has high clinical value in the early diagnosis of diabetic nephropathy.