Human Epididymis Protein 4: A Novel Biomarker for Lupus Nephritis and Chronic Kidney Disease in Systemic Lupus Erythematosus

BackgroundHuman epididymis protein 4 (HE4) is an available tumor biomarker for detecting ovarian cancer. However, it is unknown if serum HE4 could be a novel biomarker for diagnosis of lupus nephritis (LN) and chronic kidney disease (CKD) in patients with systemic lupus erythematosus (SLE). MethodsThis study enrolled 209 SLE patients, 75 patients with renal dysfunction without SLE and 32 healthy subjects. HE4 concentrations were analyzed by ELISA (enzyme-linked immunosorbent assay; Fujirebio Diagnostics, Sweden). The receiver operating characteristic (ROC) curves were constructed to assess diagnostic accuracy of HE4 for LN or CKD in SLE. ResultsSerum HE4 level was significantly higher in SLE patients than that in healthy controls (P < 0.001), especially for those with LN or CKD. It was also higher in patients with renal dysfunction without SLE than healthy controls (P < 0.001), while there was no significant difference between these patients and those with SLE with CKD (P = 0.73). Multivariate analysis showed significant association between increased HE4 and LN or CKD after controlling for confounders. ROC curves showed the cutoff values were 150.1 pM (sensitivity, 76.8%; specificity, 91.1%) for the diagnosis of LN in SLE and 233.9 pM (sensitivity, 92.9%; specificity, 93.5%) for CKD in SLE. ConclusionsIncreased serum HE4 level is closely associated with the development of LN or CKD in SLE patients. Furthermore, it can be used as a novel and useful biomarker for diagnosis of LN or CKD.